Cochlear electrogram-based insertion monitoring

Abstract

The techniques presented herein eliminate ambiguity that changes in the ECochG signals are caused by underlying drift of changes in the acoustic response of the moving electrode contacts or cochlea by simultaneously recording the ECochG signals from at least two sites in the cochlea, and tracking the position or movement of the stimulation assembly during surgery. The recorded ECochG signal, along with the location information, may be used to determine a cause of a change in the measured ECochG signal.

Description

background Technical Field

[0002] The present invention generally relates to monitoring electrocochlear graph (ECochG) signals during insertion of a stimulation assembly into a recipient. Background Art

[0003] Medical devices have provided a wide range of therapeutic benefits to recipients over the last several decades. Medical devices may include internal or implantable components / devices, external or wearable components / devices, or combinations thereof (e.g., devices having external components that communicate with implantable components). Medical devices, such as traditional hearing aids, partially or fully implantable hearing prostheses (e.g., bone conduction devices, mechanical stimulators, cochlear implants, etc.), pacemakers, defibrillators, functional electrical stimulation devices, and other medical devices, have been successful over the years in performing life-saving and / or lifestyle-improving functions and / or recipient monitoring.

[0004] Over the years, the types of medical devices and the range of functions performed by them have increased. For example, many medical devices, sometimes referred to as "implantable medical devices," now typically include one or more instruments, devices, sensors, processors, controllers, or other functional mechanical or electrical components that are permanently or temporarily implanted in a recipient. These functional devices are typically used to diagnose, prevent, monitor, treat, or manage disease / injury or its symptoms, or to study, replace, or modify anatomical structures or physiological processes. Many of these functional devices utilize power and / or data received from an external device that is part of or operates in conjunction with the implantable component. Summary of the invention

[0005] In one aspect, a method for inserting a stimulation assembly including a plurality of electrode contacts into an inner ear of a recipient is provided. The method includes: repeatedly recording a first electrocochlear graph (ECochG) signal from a primary recording site over a period of time; obtaining position information of the primary recording site associated with the recording of the first ECochG signal; and analyzing the first ECochG signal using at least the position information of the primary recording site.

[0006] In another aspect, a method is provided. The method includes: repeatedly delivering at least one acoustic stimulus to the inner ear of a recipient during insertion of a stimulation assembly into the inner ear, wherein the stimulation assembly includes a plurality of electrode contacts; recording at a primary recording site a first electrocochlear graph (ECochG) signal induced in response to the delivery of the at least one acoustic stimulus; recording position information of one or more portions of the stimulation assembly during monitoring of the first ECochG signal; and monitoring an acoustic response of the inner ear based at least on the first ECochG signal and the position information.

[0007] In another aspect, one or more non-transitory computer-readable storage media are provided. The one or more non-transitory computer-readable storage media include instructions that, when executed by a processor, cause the processor to: obtain a second electrocochlear graph (ECochG) signal repeatedly recorded via a tip electrode of the stimulation assembly during insertion of the stimulation assembly into an inner ear of a recipient; obtain a first ECochG signal repeatedly recorded via at least one other electrode of the stimulation assembly during insertion of the stimulation assembly into the inner ear; and analyze the second ECochG signal recorded via the tip electrode relative to the first ECochG signal recorded via at least one other electrode to characterize an acoustic response of the inner ear.

[0008] In another aspect, a system is provided. The system includes: a user interface; a network interface for communicating with an implantable medical device, the implantable medical device including a plurality of electrode contacts configured to be implanted in a recipient; a memory; and one or more processors configured to: obtain a recording of a first electrocochlear graph (ECochG) signal from a primary recording site during implantation of the plurality of electrode contacts in the recipient; determine position information of the primary recording site associated with the recording of the first ECochG signal; and analyze the recording of the first ECochG signal using at least the position information. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Embodiments of the present invention are described herein with reference to the accompanying drawings, in which:

[0010] Figure 1A is a graph showing cochlear microphonic potential magnitudes associated with electrocochlear graph (ECochG) signals captured during insertion of a stimulation assembly into a recipient's inner ear;

[0011] Figure 1B is a graph showing cochlear microphonic potential magnitudes associated with ECochG signals captured during insertion of the stimulation assembly into the recipient's other inner ear;

[0012] Figure 2 is a schematic diagram showing a cochlear implant system in the head of an implant recipient and an ECochG insertion monitoring system associated with the cochlear implant system according to certain embodiments presented herein;

[0013] Figure 3 is a diagram showing some embodiments according to the present invention Figure 2 Schematic diagram of the cochlear implant system and ECochG insertion monitoring system showing a side view of the recipient's head;

[0014] Figure 4 is a diagram showing some embodiments according to the present invention Figure 2 Schematic diagram of a cochlear implant system and ECochG insertion monitoring system showing components of the cochlear implant system without the recipient's head for simplicity;

[0015] Figure 5 According to certain embodiments presented herein Figure 2 Block diagram of the cochlear implant system and ECochG insertion monitoring system;

[0016] Fig. 6A , 6B , 6C, 6D, 6E, and 6F are a series of graphs schematically illustrating recording of ECochG signals during insertion of a stimulation assembly into an inner ear of a recipient according to certain embodiments presented herein;

[0017] Fig. 7A is a graph illustrating cochlear microphonic potential magnitudes associated with ECochG signals recorded during insertion of a stimulation assembly into an inner ear of a recipient in accordance with certain embodiments presented herein;

[0018] Figure 7B is a diagram showing some embodiments according to the present invention. Fig. 7A A graph of the angular insertion depth of the electrode contacts during insertion of the stimulation assembly;

[0019] Figure 7C is at a fixed target location within the inner ear according to certain embodiments presented herein Fig. 7A A magnified (enlarged) view of the magnitude of the cochlear microphonic potential;

[0020] Fig. 8A is a graph illustrating cochlear microphonic potential magnitudes associated with ECochG signals recorded during insertion of a stimulation assembly into an inner ear of a recipient in accordance with certain embodiments presented herein;

[0021] Figure 8B is a diagram showing some embodiments according to the present invention. Fig. 8A A graph of the angular insertion depth of the electrode contacts during insertion of the stimulation assembly;

[0022] Figure 8C is at a fixed target location within the inner ear according to certain embodiments presented herein Fig. 7A A magnified (enlarged) view of the magnitude of the cochlear microphonic potential;

[0023] Fig.9A is a graph illustrating cochlear microphonic potential magnitudes associated with ECochG signals recorded during insertion of a stimulation assembly into an inner ear of a recipient in accordance with certain embodiments presented herein;

[0024] Fig. 9B is a diagram showing some embodiments according to the present invention. Fig.9A A graph of the angular insertion depth of the electrode contacts during insertion of the stimulation assembly;

[0025] Fig. 9C is a diagram showing the same cochlear location according to certain embodiments presented herein. Fig.9A A graph of a change in the ratio of the magnitude of the cochlear microphonic potential recorded from the primary recording site relative to the magnitude of the cochlear microphonic potential previously recorded from the second recording site;

[0026] Fig. 10A is a graph illustrating cochlear microphonic potential magnitudes associated with ECochG signals recorded during insertion of a stimulation assembly into an inner ear of a recipient in accordance with certain embodiments presented herein;

[0027] Fig. 10B is a diagram showing some embodiments according to the present invention. Fig. 10A A graph of the angular insertion depth of the electrode contacts during insertion of the stimulation assembly;

[0028] Fig. 10C is a diagram showing the same cochlear location according to certain embodiments presented herein. Fig. 10A A graph of a change in the ratio of the magnitude of the cochlear microphonic potential recorded from the primary recording site relative to the magnitude of the cochlear microphonic potential previously recorded from the second recording site;

[0029] Fig.11 is a cross-sectional view illustrating a cochlea and a stimulation assembly according to certain embodiments presented herein, showing the location of the stimulation assembly within the cochlea;

[0030] Fig.12 is a schematic diagram illustrating a vestibular stimulator system and an ECochG insertion monitoring system associated with the vestibular stimulator system according to certain embodiments presented herein;

[0031] Fig.13 is a flow chart of a method according to certain embodiments presented herein; and

[0032] Fig.14 is a flow chart of another method according to certain embodiments presented herein. DETAILED DESCRIPTION

[0033] Hearing / hearing prosthesis recipients suffer from different types of hearing loss (e.g., conductive and / or sensorineural) and / or different degrees / severities of hearing loss. However, it is now common that many hearing prosthesis recipients retain some residual natural hearing ability (residual hearing) after receiving a hearing prosthesis. That is, hearing prosthesis recipients typically retain at least some natural ability to hear sounds without the assistance of their hearing prosthesis. For example, cochlear implants can now be implanted in a manner that retains at least some of the recipient's cochlear hair cells and natural cochlear function (particularly in the low-frequency region of the cochlea).

[0034] Electrocochlear gram (ECoG or ECochG) refers to a clinical measurement technique that can be used, for example, to assess a recipient's residual hearing. ECochG involves delivering an acoustic stimulus to the recipient's cochlea, and recording one or more responses of the cochlea to the acoustic stimulus (ECochG responses or ECochG signals). For example, during certain ECochG measurement procedures, a preselected / predetermined click or tone is acoustically delivered to the recipient's inner ear, and the ECochG response / signal is recorded, for example, using electrodes in or near the patient's middle ear or inner ear.

[0035] ECochG recording can be used during the insertion of the stimulation assembly into the cochlea. For example, conventional devices record ECochG signals from the top-most electrode and monitor the amplitude and latency of the cochlear microphonic potential (CM). A drop in the amplitude of the cochlear microphonic potential and / or a sudden change in latency is often interpreted as meaning that something is wrong, and in some cases, the surgeon will withdraw the stimulation assembly or otherwise manipulate the position of the stimulation assembly in an attempt to restore the cochlear microphonic potential.

[0036] However, it is difficult for a user (e.g., surgeon) to determine whether observed changes in the ECochG signal (e.g., dips and jumps in cochlear microphonic potentials) indicate different localized patterns of passage of the recording electrode through the cochlear anatomy (e.g., due to outer hair cell (OHC) health) or changes in the acoustic response of the cochlea (e.g., altered contact with the basilar membrane, trauma, etc.). This makes it very difficult to interpret ECochG signal changes during cochlear implant surgery as anything other than a problem where all dips in amplitude are equal, especially when creating automated ECochG interpretation systems.

[0037] For example, Figure 1A is a graph of a portion of an ECochG signal, namely, cochlear microphonic potential (CM) magnitude 101 (A), varying over time for a first stimulation assembly surgically inserted into a first cochlea. Figure 1B is a graph showing cochlear microphonic potential magnitude 101 (B) over time for surgical insertion of a second stimulation assembly into a second cochlea. Figure 1A and 1BThe cochlear microphonic potential magnitudes 101(A) and 101(B) shown in the Figures represent recordings from the topmost electrode contact for 500 Hz probe stimulation, respectively. Note that in both cases, the cochlear microphonic potential magnitudes rose and fell several times during the insertion process, and it is difficult to determine the cause of each drop in magnitude based on these recordings alone.

[0038] The technology presented herein operates by simultaneously recording ECochG signals from at least two locations in the cochlea, and tracking the position or movement of the stimulation assembly during surgery to eliminate the ambiguity of ECochG signal changes caused by (1) moving electrode contacts or (2) underlying shifts in the acoustic response of the cochlea. This enables the ECochG signals at different time points from substantially the same or very similar positioning (e.g., the same pure tone frequency region) to be compared when the total insertion depth of the stimulation assembly changes. The position or relative movement of the stimulation assembly can be tracked by impedance monitoring of the electrode array contacts, analysis of the phase / delay of the ECochG signal, visual tracking (surgical microscope) or radiographic video imaging such as fluoroscopy. The recorded ECochG signal, together with the position information, can be used to determine the cause of the measured ECochG signal change, which is not easy to determine in the current state of the art. By improving the interpretation of the recorded ECochG signal, the surgeon should be able to preserve hearing more confidently during electrode insertion.

[0039] As used herein, the "position" of an electrode contact generally refers to the insertion depth (e.g., angular insertion depth) of the electrode contact in the inner ear (e.g., cochlea). However, the "position" of an electrode contact may also include the relative proximity of the electrode contact to the wall of the inner ear (e.g., modiolar proximity, lateral wall proximity, etc.), the distance from the mid-modiolar axis, or other information about the placement or position of one or more parts of the stimulation assembly.

[0040] Typically, the techniques presented herein record ECochG signals and electrode contact position information, and then analyze this information to determine whether the detected ECochG signal changes are due to local anatomical changes when the stimulation assembly moves through the inner ear (e.g., no surgical intervention / repair is required), or to determine whether the detected ECochG signal changes are due to changes in the acoustic response of the cochlea (e.g., surgical intervention / repair is required). According to certain embodiments presented herein, the system repeatedly (e.g., continuously, periodically, etc.) records ECochG signals from a "primary recording site" and possible "secondary recording sites" within the inner ear (e.g., cochlea). In these embodiments, the stimulation assembly includes an elongated carrier member having a plurality of longitudinally spaced electrode contacts. As further described below, different options for repeatedly recording ECochG signals during insertion of the stimulation assembly into the inner ear and different options for analyzing ECochG signals with electrode contact position information are presented herein.

[0041] In some embodiments, the secondary recording site is fixed to the most distal electrode contact of the stimulation assembly, which means that the position / location of the secondary recording site (e.g., insertion depth, modiolar proximity, etc.) will change over time as the stimulation assembly is gradually inserted into the inner ear or otherwise manipulated, but the electrode used to make the secondary recording does not change (i.e., the second recording site is the most distal electrode). However, in these embodiments, one or more primary recording sites within the inner ear are at a fixed position (e.g., a predetermined insertion depth), which means that the position / location of one or more secondary sites will remain substantially constant / fixed over time as the stimulation assembly is gradually inserted into the inner ear or otherwise manipulated, but the electrode contact(s) used to make the second recording(s) will change over time (e.g., the electrode changes to the electrode that is closest to the predetermined constant position within the inner ear). The positioning of the one or more primary recording sites can be, for example, near the base of the cochlea or another fixed position with a robust ECochG response (e.g., if the ECochG signal is very small or non-existent, no recording will be made at the base of the cochlea).

[0042] According to an alternative embodiment, the secondary recording site and the one or more primary recording sites are each fixed to a specific electrode contact of the stimulation assembly, which means that the position / location (e.g., insertion depth, modiolar proximity, etc.) of the secondary recording site and the one or more primary recording sites will change over time as the stimulation assembly is gradually inserted into the inner ear or otherwise manipulated, but the electrode used to make the secondary recording and the one or more secondary recordings do not change. The secondary recording site can be, for example, the most apical electrode, and the one or more primary recording sites are each a more basal electrode (e.g., an electrode spaced a certain distance from the most apical electrode).

[0043] According to these embodiments, for each ECochG signal recording, the inner ear position of the electrode when recording is performed, and the possible time of recording are also obtained / recorded, and associated with the corresponding ECochG signal recording. This information is then used by the system to analyze the ECochG signal in a relative manner, thereby determining whether the ECochG signal change is caused by a change in the local anatomical structure when the stimulation component moves through the inner ear, or whether the detected ECochG signal change is caused by a change in the acoustic response of the cochlea (e.g., comparing the ECochG signals over time at one or more known positions to determine whether the ECochG changes observed at the topmost electrode are caused by changes in the local anatomical structure or the acoustic response of the cochlea). Therefore, the technology presented herein can provide a clearer explanation of the ECochG signal and the effects on the surgeon, thereby bringing improved surgical interventions to maximize / balance hearing preservation and the insertion depth of the stimulation component. The technology presented herein also helps to create an algorithm that automates the interpretation of the ECochG signal, and provides surgeons with more meaningful information to guide their decision-making process, and maximizes the preservation of residual hearing and the overall results.

[0044] Only for ease of description, the technology presented herein is mainly described with reference to a specific implantable medical device system, i.e., a cochlear implant system. However, it should be understood that the technology presented herein can also be partially or completely implemented by other types of implantable medical devices, including other implantable devices with the ability to record ECochG signals. For example, the technology presented herein can be implemented by other auditory prosthesis systems including one or more other types of auditory prostheses (e.g., middle ear auditory prostheses, bone conduction devices, direct sound stimulators, electroacoustic prostheses, auditory brain stimulators, combinations or variations thereof, etc.). The technology presented herein can also be implemented by a dedicated tinnitus treatment device and a tinnitus treatment device system. In other embodiments, the technology presented herein can also be implemented by a vestibular device (e.g., a vestibular implant), a visual device (i.e., a bionic eye), a sensor, a pacemaker, a drug delivery system, a defibrillator, a functional electrical stimulation device, a catheter, an epileptic seizure device (e.g., a device for monitoring and / or treating epileptic events), a sleep apnea device, an electroporation device, etc., or used in combination with them.

[0045] As used herein, an ECochG signal may include one or more different stimulus-related potentials (e.g., a set of ECochG responses), including cochlear microphonic potentials (CM), cochlear sum potentials (SP), and auditory nerve neurophonic (ANN) / auditory nerve action potentials (AP), wherein these parameters are measured / recorded independently or in various combinations in response to delivering acoustic stimulation to the inner ear. The cochlear microphonic potential is an alternating current (AC) voltage that reflects the waveform of the acoustic stimulus under low to medium levels of acoustic stimulation. The cochlear microphonic potential is generated by the outer hair cells of the organ of Corti and depends on the proximity of the (one or more) recording electrodes to the stimulated hair cells. In general, the cochlear microphonic potential is proportional to the displacement of the basilar membrane.

[0046] The sum potential is the direct current (DC) response of the outer hair cells of the organ of Corti as they move with the basilar membrane (i.e., reflecting the time-displacement pattern of the cochlear partitions in response to the stimulus envelope). The sum potential is the stimulation-related potential of the cochlea and can be viewed as a DC (unidirectional) shift in the baseline of the cochlear microphonic potential. The direction of this shift (i.e., positive or negative) depends on a complex interaction between the stimulation parameters and the position of the recording electrode.

[0047] The auditory nerve neural tone (auditory nerve action potential) represents the summed response to the synchronous excitation of nerve fibers in response to acoustic stimulation, and it is presented as an alternating current voltage. The auditory nerve neural tone is characterized by a series of short, mainly negative peaks, including a first negative peak (N1) and a second negative peak (N2). The auditory nerve neural tone also includes a magnitude and a delay. The magnitude of the auditory nerve neural tone reflects the number of fibers being excited, and the delay of the auditory nerve neural tone is measured as the time between the start and the first negative peak (N1). Typically, ECochG signal recording can be completed within a short period of time (e.g., a few milliseconds after the initial delivery of the acoustic stimulus), and it is not necessary to wait until after the acoustic stimulation is completed.

[0048] For ease of description, this article mainly refers to the analysis of cochlear microphonic potentials and specifically the analysis of cochlear microphonic potential magnitudes at different inner ear locations to describe these techniques. However, it should be recognized that the specific reference to the magnitude of the cochlear microphonic potential is only exemplary, and the techniques presented in this article can be implemented with other parameters of the ECochG signal, including the sum potential, the auditory nerve neural sound. The relative analysis of these parameters of the ECochG signal may include the analysis of one or more of the parameter magnitudes, parameter delays, etc.

[0049] First reference Figure 2-5, for ease of description, these figures are generally described together, an exemplary cochlear implant system 102 can be implanted in the head 141 of a human, animal, or other recipient (each referred to herein as a "recipient"). Cochlear implant system 102 includes an external component 104 and an implantable component 112. Implantable component 112 is sometimes referred to as a "cochlear implant." Cochlear implant system 102 works in conjunction with an electrocochlear graph (ECoG or ECochG) insertion monitoring system 180.

[0050] Figure 2 is a schematic diagram showing implantable component 112 implanted in head 141 of a recipient, and Figure 3 is a schematic diagram showing an outer member 104 configured to be positioned adjacent a recipient's head 141 . Figure 4 Another schematic diagram of cochlear implant system 102 is included, including both external component 104 and implantable component 112, but without the recipient's head for the sake of clarity. Figure 5 is a block diagram illustrating additional details of cochlear implant system 102 and ECochG insertion monitoring system 180 associated with cochlear implant system 102 according to certain embodiments presented herein.

[0051] As noted, cochlear implant system 102 includes an external component 104 configured to be attached directly or indirectly to the body of a recipient and an implantable component 112 configured to be implanted in the recipient. In the example of FIGS. 1-4 , external component 104 includes a sound processing unit 106, which is an off-the-ear (OTE) sound processing unit, sometimes referred to as an “OTE component.” Sound processing unit 106 is configured to send data and power to implantable component 112 as described below.

[0052] exist Figure 2-5 In the arrangement shown, the sound processing unit 106 includes a generally cylindrical housing 105 that is configured to magnetically couple to a recipient's head 141. For example, the sound processing unit 106 may include an integrated external magnet 150 that is configured to magnetically couple to an implantable magnet 152 in the implantable component 112. The sound processing unit 106 also includes an integrated external coil 108 that is configured to wirelessly (e.g., inductively) couple to an implantable coil 114 of the implantable component 112 as described below. In Figures 1-3, the external magnet 150 is shown using dashed lines to indicate that it is integrated within the housing 105 of the sound processing unit 106. In Figure 5 , external magnet 150 and implantable magnet 152 are shown using dashed lines, indicating that external coil 108 and implantable coil 114 are disposed around magnet 150 and magnet 152, respectively.

[0053] will realize that Figure 2-5The arrangement shown in is only schematic, and other arrangements are feasible. Specifically, the OTE sound processing unit 106 is merely a schematic of an external device that can operate with the implantable component 112. For example, in an alternative example, the external component may include a behind-the-ear (BTE) sound processing unit or a micro-BTE sound processing unit and a separate external coil assembly. In general, the BTE sound processing unit includes a housing that is shaped to be worn on the recipient's outer ear and is connected to a separate external coil assembly via a cable, wherein the external coil assembly is configured to be magnetically coupled and inductively coupled to the implantable coil 114. It should be understood that alternative external components can be located in the recipient's ear canal, worn on the body, etc.

[0054] More specifically, the OTE sound processing unit 106 is used for communication between the ECochG insertion monitoring system 180 and the cochlear implant 112. Therefore, during the surgical procedure, the OTE sound processing unit 106 can be replaced by any other device capable of communicating with the ECochG insertion monitoring system 180 and the cochlear implant 112. In some embodiments, the OTE sound processing unit 106 can be a so-called "surgical processor" that has less capabilities than the OTE sound processing unit 106 (e.g., no sound processing logic, etc.). In various embodiments, communication between the ECochG insertion monitoring system 180 and the OTE sound processing unit 106 or another device that operates in place of the OTE sound processing unit 106 can be communicated via a wireless or wired connection.

[0055] In addition, despite Figure 2-5 The cochlear implant system 102 is shown to include an arrangement of external components, but it should be appreciated that embodiments of the present invention may be implemented in a cochlear implant system having an alternative arrangement. For example, the embodiments presented herein may be implemented by a fully implantable cochlear implant or other fully implantable medical device. A fully implantable medical device is one in which all components of the device are configured to be implanted beneath the skin / tissue of a recipient. Because all components are implantable, the fully implantable medical device operates without the need for external devices / components, at least for a limited period of time. However, the external components may be used, for example, to charge an internal power source (battery) of the fully implantable medical device.

[0056] Return to Figure 2-5 A specific example is, Figure 5The sound processing unit 106 is shown to include one or more input devices 113 configured to receive input signals (e.g., sound or data signals). The one or more input devices 113 include one or more sound input devices 118 (e.g., microphones, audio input ports, telecoils, etc.), one or more auxiliary input devices 119 (e.g., audio ports such as direct audio input (DAI), data ports such as universal serial bus (USB) ports, cable ports, etc.), and wireless transmitter / receiver (transceiver) 120. However, it should be appreciated that the one or more input devices 113 may include additional types of input devices and / or fewer input devices (e.g., the wireless transceiver 120 and / or one or more auxiliary input devices 119 may be omitted).

[0057] The sound processing unit 106 also includes an external coil 108, a charging coil 121, a tightly coupled interface circuit system (transceiver) 122 (sometimes referred to as a radio frequency (RF) interface circuit system 122), at least one rechargeable battery 123, and a processing module 124. The processing module 124 includes one or more processors 125 and a memory device (memory) 126. The memory device 126 may include any one or more of the following: non-volatile memory (NVM), ferroelectric random access memory (FRAM), read-only memory (ROM), random access memory (RAM), magnetic disk storage media device, optical storage media device, flash memory device, electrical, optical or other physical / tangible memory storage device. The one or more processors 125 are, for example, microprocessors or microcontrollers.

[0058] The implantable component 112 includes an implant body (main module) 134, a lead region 136, and an intracochlear stimulation assembly 116, all configured to be implanted beneath the skin / tissue of a recipient. Magnets 150 and 152 magnetically couple the external component 104 to the implantable component 112 through the skin / tissue. The implant body 134 generally includes a hermetically sealed housing 138 in which the RF interface circuitry 140 and the stimulator unit 142 are disposed. The implant body 134 also includes an internal / implantable coil 114, which is generally external to the housing 138 but is connected to the stimulator unit 142 via a hermetic feedthrough ( Figure 5 ) is connected to the transceiver 140.

[0059] The stimulation assembly 116 is configured to be at least partially implanted in the cochlea of ​​the recipient. The stimulation assembly 116 includes a plurality of longitudinally spaced intracochlear electrical stimulation contacts (electrodes) 144 that collectively form a contact or electrode array 146 for delivering electrical stimulation (electrical current) to the cochlea of ​​the recipient. The stimulation assembly 116 extends through an opening in the cochlea of ​​the recipient (e.g., a cochlear fenestration, a round window, etc.) and has a proximal end connected to a stimulator unit 142 via a lead region 136 and an airtight feedthrough. The lead region 136 includes a plurality of conductors (wires) that electrically couple the electrodes 144 to the stimulator unit 142. The implantable component 112 also includes an electrode outside the cochlea, sometimes referred to as an extracochlear electrode (ECE) 139.

[0060] As noted, cochlear implant system 102 includes an external coil 108 and an implantable coil 114. In certain exemplary embodiments, external magnet 150 is fixed relative to external coil 108, while implantable magnet 152 is fixed relative to implantable coil 114. Magnets 150 and 152 can facilitate operational alignment of external coil 108 with implantable coil 114, thereby enabling external component 104 to transmit data and power to implantable component 112 via a tightly coupled wireless link formed between coils 108 and 114. In certain examples, the tightly coupled wireless link is a radio frequency (RF) link. However, various other types of energy transfer (e.g., infrared (IR), electromagnetic, capacitive, and inductive transfer) may be used to transfer power and / or data from the external component to the implantable component, and thus, Figure 2-5 For example, external coil 108 may be in electrical communication with a power source (eg, rechargeable battery 123 ) and may induce a current in implantable coil 114 to supply power to implantable component 112 via an inductive link between coils 108 and 114 .

[0061] The ECochG insertion monitoring system 180 includes, among other things, a user interface 181, one or more processors 182, a network interface (e.g., a wireless module) 183, and a memory device (memory) 184 storing ECochG insertion monitoring logic 185. The memory device 184 may include any one or more of the following: non-volatile memory (NVM), ferroelectric random access memory (FRAM), read-only memory (ROM), random access memory (RAM), magnetic disk storage media device, optical storage media device, flash memory device, electrical, optical or other physical / tangible memory storage device. The one or more processors 182 are, for example, microprocessors or microcontrollers configured to execute instructions associated with the ECochG insertion monitoring logic 185.

[0062] Network interface 183 enables communication with external component 104 and / or cochlear implant 112. For example, network interface 183 may include a wireless module similar to wireless module 120 described elsewhere herein for wirelessly communicating with external component 104 (or cochlear implant 112 if implemented with a wireless module).

[0063] For example, the user interface 181 includes: one or more input devices through which the ECochG insertion monitoring system 180 receives input from the user; and one or more output devices by means of which the ECochG insertion monitoring system 180 can provide output to the user. The one or more input devices may include physically actuatable user interface elements (e.g., buttons, switches, or dials), touch screens, keyboards, mice, pens, and voice input devices, among other input devices. The one or more output devices may include displays, speakers, and printers, among other output devices.

[0064] The ECochG insertion monitoring system 180 may be implemented by a suitable computing system, environment, or configuration, including but not limited to personal computers, server computers, handheld devices, laptop devices, multiprocessor systems, microprocessor-based systems, programmable consumer electronics (e.g., smart phones), network PCs, minicomputers, mainframe computers, tablet computers, distributed computing environments including any of the above, and the like.

[0065] According to the embodiments presented herein, ECochG insertion monitoring system 180 is configured to record ECochG signals from a primary recording site and possibly one or more secondary sites when stimulation assembly 116 is inserted into the cochlea of ​​a recipient. More specifically, ECochG insertion monitoring system 180 is configured to capture ECochG signals from the cochlea using electrodes 144 of electrode array 146.

[0066] In a normal or fully functional ear, sound pressure or sound waves (i.e., sound signals) are collected by the outer ear and pass through the ear canal via a channel. Disposed across the far end of the ear canal is an eardrum that vibrates in response to sound waves. This vibration is coupled to the oval window through three bones of the middle ear. The middle ear bones are used to filter and amplify sound waves, causing the oval window to pivot or vibrate in response to the vibration of the eardrum. This vibration sets up fluid motion waves of the perilymph within the cochlea to activate the cochlear hair cells. The activation of the hair cells causes the generation of appropriate nerve impulses and is transmitted to the brain through the recipient's spiral ganglion cells and the auditory nerve, where these nerve impulses are perceived as sound.

[0067] As noted above, usually the hearing prosthesis recipient retains at least a portion of this normal hearing function (i.e. retains at least one residual hearing). Therefore, the cochlea of ​​the hearing prosthesis recipient can be acoustically stimulated when the sound signal is delivered to the recipient's outer ear without the help of the hearing prosthesis itself. In some recipients, the normal hearing function can be enhanced by using an acoustic transducer in or near the outer ear and / or the ear canal. In these recipients, the acoustic transducer is used for, for example, filtering, enhancing and / or amplifying sound signals, which are delivered to the cochlea by the middle ear bones and the oval window, thereby producing the fluid motion wave of the perilymph in the cochlea. In other recipients, the normal hearing function can be enhanced by using a mechanical transducer coupled to the bone (e.g., skull, jawbone, etc.) of an individual. In such recipients, the mechanical transducer delivers vibration to the individual's bone, and the vibration is relayed to the cochlea so as to produce the fluid motion wave of the perilymph in the cochlea.

[0068] Therefore, the ECochG recording used in accordance with the embodiments presented herein can be initiated by the ECochG insertion monitoring system 180. ECochG recording involves delivering an acoustic stimulus to the cochlea of ​​the recipient and recording one or more responses of the cochlea to the acoustic stimulus. As used herein, acoustic stimulation refers to any type of stimulation that is delivered in a certain manner so as to establish a fluid motion wave of the perilymph within the cochlea and then activate the hair cells inside the cochlea. Therefore, the acoustic stimulation used to perform ECochG recording in accordance with the embodiments presented herein can be delivered via the normal hearing function of the recipient, via an acoustic transducer, via a mechanical transducer, a combination thereof, and the like.

[0069] Figure 5 An embodiment is shown in which an acoustic transducer in the form of an external speaker 186 delivers acoustic stimulation 187 to the cochlea of ​​a recipient. Figure 5 Cochlear implant 112 is also shown to include a recording module 188 configured to record ECochG signals induced in the cochlea by acoustic stimulation. Recording module 188 may include, for example, a sense amplifier configured to digitally record ECochG signals / responses present on input lines connected to one or more of electrodes 144. Data recorded by the sense amplifier may be stored in a buffer in some embodiments.

[0070] RF interface circuitry 140 and 122 cooperate to provide ECochG signal data (e.g., captured ECochG signals and data associated with the captured ECochG signals) to sound processing unit 106, where the ECochG signal data is then provided to ECochG insertion monitoring system 180. The ECochG signal data is provided at Figure 5 The center is generally indicated by arrow 190.

[0071] As noted above, this article presents several options for recording and analyzing ECochG signals during insertion of a stimulation assembly into the cochlea. These options are described in more detail below. For ease of illustration, the following description also refers to the Figure 2-5 The cochlear implant system 102 and the ECochG insertion monitoring system 180 are explained.

[0072] First reference Figures 6A-6F , a series of diagrams illustrating advancement of the stimulation assembly 116 into the cochlea 127 are shown. Figures 6A-6F Each of the figures shows a secondary recording site (represented by a 5-pointed star shape), a primary recording site (represented by a 7-pointed star shape), and a target position / location of the primary recording site (represented by a bull's eye shape). In this example, the target position is selected to be near an angular insertion depth of approximately 45°.

[0073] like Fig. 6A As shown in , the stimulation assembly 116 is inserted into the cochlea 127, and an acoustic stimulus 187 (e.g., a 500 Hz (Hz) tone) is repeatedly delivered to the cochlea 127. The recording module 188 records a voltage trace of at least a few milliseconds of the acoustically evoked response (ECochG signal) at the second recording site (i.e., the topmost electrode contact). This process continues repeatedly until the stimulation assembly 116 is inserted, the surgeon stops the insertion, or some other stop condition is reached. As shown, the second recording site is fixed relative to the stimulation assembly 116, and moves relative to the cochlea 127 as the stimulation assembly is advanced into the cochlea.

[0074] When the stimulation assembly 116 is inserted, the ECochG insertion monitoring system 180 repeatedly (e.g., periodically, continuously, etc.) estimates the position of the second recording site (the topmost electrode) relative to the cochlea 127 (e.g., determining the angular insertion depth of one or more electrode contacts within the cochlea at least twice per second, and optionally also determining the position of the electrode contacts within a cross-sectional plane of the cochlear turn at each angle or in a cylindrical coordinate system or other three-dimensional coordinate system).

[0075] As noted, the ECochG insertion monitoring system 180 obtains (e.g., receives, determines, etc.) a target location in the cochlea 127 for use as a primary recording location. The ECochG insertion monitoring system 180 also records what is referred to herein as a "second recording reference" when the second location initially reaches the target location. That is, as used herein, the second reference recording is an ECochG signal (or a parameter of an ECochG signal) recorded when the second recording location and the primary recording location are at the same cochlear location (e.g., when the most apical electrode reaches the predetermined target location).

[0076] When the stimulation assembly 116 is inserted, the topmost electrode will move past the target position because, as noted, the main recording site moves relative to the stimulation assembly 116 and attempts to maintain a fixed position relative to the cochlea 127. Once the selected electrodes other than the topmost electrode reach the predetermined target position, the recording module 188 records a voltage trace of at least several milliseconds of the acoustically induced response (ECochG signal) at the selected electrode in response to the acoustic stimulation 187. That is, as noted, the acoustic stimulation 187 is delivered to the cochlea 127, and the ECochG signal induced at the predetermined target position is recorded by the selected electrode. This means that the ECochG insertion monitoring system 180 records the ECochG signals from both the second recording site (the topmost electrode) and the main recording site (the selected electrode at the predetermined target position) in an interlaced or simultaneous manner. Again, this process repeats and continues until the stimulation assembly 116 is inserted, the surgeon stops the insertion, or some other stop condition is reached. However, since the primary recording site is fixed relative to the cochlea 127, the primary recording site changes relative to the stimulation assembly 116, which means that different electrodes will be used as the primary recording site as insertion progresses. Fig.6D , 6E Such use of different electrodes (ie, progressively lower electrodes) is schematically shown in 6F.

[0077] The predetermined target position can be selected, for example, by tracking the magnitude of the ECochG signal (acoustically evoked response) at the second recording site and the location of the second recording site in the cochlea 127 to determine when the magnitude of the ECochG signal first exceeds the limit. Once this is detected, the location where the ECochG signal first exceeds the limit is set as the target position of the primary recording site. Alternatively, the system can set the target position a priori.

[0078] In operation, based on the most recent position estimate of the stimulation assembly 116, the ECochG insertion monitoring system 180 can continuously determine the electrode contact closest to the target location, update the primary recording site to this electrode contact, and record at least a few milliseconds of the voltage trace of the acoustic evoked response (ECochG signal) at the primary recording site (the electrode contact closest to the target location / position). If the stimulation assembly 116 has not moved significantly, the secondary recording site and the primary recording site can use the same electrode contact. As the electrode is inserted deeper into the cochlea, the secondary recording site and the primary recording site will be farther and farther away from each other.

[0079] The ECochG insertion monitoring system 180 monitors the ECochG signal recorded from the second recording site based on the ECochG signal recording from the main recording site. For example, the ECochG insertion monitoring system 180 compares the second recording reference (e.g., the magnitude of the ECochG signal when the top electrode was at the target position) with the most recent recording from the main recording site. The system can, for example, plot the difference or ratio of the main recording site magnitude compared to the second recording site magnitude from the target position. After optionally compensating for the position difference, if the main recording site magnitude is less than the second recording reference, and the difference exceeds a limit, such as 30% or less, the system can determine that a significant decrease in the acoustically evoked response has occurred.

[0080] Fig. 7A , 7B 7C schematically illustrate exemplary monitoring parameters of an ECochG signal obtained during an exemplary insertion of the stimulation assembly 116 into the cochlea 127. However, Figures 6A-6F The target position of the primary recording site is approximately 45° at the insertion depth, while Figures 7A-7C In the example shown, the target position of the main recording site is approximately 90°.

[0081] More specifically, Fig. 7A Included is a trace / line 731 representing the cochlear microphonic potential (CM) amplitude / magnitude recorded from the second recording site (i.e., the topmost electrode contact) during insertion of the stimulation assembly 116. Fig. 7A , line 733 represents the magnitude of the cochlear microphonic potential recorded from the primary recording site (ie, the fixed target location) at an angular insertion depth (AID) of approximately 90°. Figure 7B The angular insertion depth of the most distal electrode contact during the entire insertion (line 735) is shown, as well as the angular insertion depth of the other electrode contacts when they are closest to the 90° target position. Figure 7B , the number of electrodes increases from the topmost electrode contact inserted into the cochlea 127 (i.e., electrode 1) to the bottommost contact (electrode 19 in this case). Figure 7B The lines illustrating the angular insertion depths of the electrode contacts 2 - 19 are not individually marked.

[0082] Figure 7C is the value of the cochlear microphonic potential at the fixed target position (90°AID) Fig. 7A As shown, although there are some small fluctuations in magnitude, which can be attributed to noise and small position changes of the recording electrode, the magnitude is stable, indicating that there was no interference with acoustic hearing during this insertion period and that any decrease in the magnitude of the cochlear microphonic potential observed at the tip electrode is simply due to local anatomical changes.

[0083] Fig. 8A , 8B 8C schematically illustrate exemplary monitoring parameters of an ECochG signal obtained during another exemplary insertion of the stimulation assembly 116 into the cochlea 127. However, Figures 6A-6F The target position of the primary recording site is approximately 45° at the insertion depth, while Figures 7A-7C In the example shown, the target position of the main recording site is approximately 160°.

[0084] More specifically, Fig. 8A Included is a trace / line 831 representing the cochlear microphonic potential (CM) amplitude / magnitude recorded from the second recording site (i.e., the apical-most electrode contact). Fig. 8A , line 833 represents the cochlear microphonic potential magnitude recorded from the primary recording site (ie, the target fixation position) at an angular insertion depth (AID) of approximately 160°. Figure 8B The angular insertion depth of the most distal electrode contact in the entire insertion (line 835) is shown, as well as the angular insertion depth of the other electrode contacts when they are closest to the 160° target position to monitor the magnitude of the cochlear microphonic potential. Figure 8B In FIG. 1 , the number of electrodes increases from the topmost electrode contact inserted into the cochlea 127 (i.e., electrode 1) to the bottommost contact (electrode 12 in this case). For ease of illustration, in FIG. Figure 8B The lines illustrating the angular insertion depths of the electrode contacts 2 - 12 are not individually marked.

[0085] Figure 8C is the value of the cochlear microphonic potential at the fixed target position (160°AID) Fig. 8A 833 ). As shown, small fluctuations in the cochlear microphonic potential magnitude can be attributed to noise and small position changes of the recording electrode. In addition, the cochlear microphonic potential magnitude at the fixed target position is stable until a time point of approximately 120 seconds, when there is a large drop in the cochlear microphonic potential magnitude recorded at both the top electrode and the fixed target position. This indicates a significant interference with acoustic hearing during insertion at approximately 120 seconds, and an earlier drop in the cochlear microphonic potential magnitude from the top-most electrode contact at 100 seconds ( Fig. 8A The line 141) is due to the local cochlear anatomy.

[0086] exist Figures 8A-8CIn the example of, when significant interference with acoustic hearing is detected, the ECochG insertion monitoring system 180 generates an output to initiate a corrective action. For example, the ECochG insertion monitoring system 180 may issue a notification or warning (e.g., an audible warning, a visual warning, a tactile warning, etc.) to the surgeon or other user. In addition or alternatively, the ECochG insertion monitoring system 180 may provide a recommendation to the surgeon based on the ECochG signal and the position information (e.g., recommending to stop insertion, recommending to retract the stimulation component 45°). In the case of a robotic or automated insertion system, the ECochG insertion monitoring system 180 may be integrated as part of the control subsystem and cause the robotic or automated insertion to perform the recommended action (e.g., stop insertion, retract the stimulation component 45°). In some embodiments, feedback on the original change metric (which may or may not exceed a limit) may be provided. For example, this feedback may indicate the extent to which the CM magnitude at a fixed target position has deviated from a reference response. This feedback may be provided, for example, by continuous visual / audio / tactile feedback (e.g., a number updated on a screen).

[0087] As noted, the present invention has been generally described with reference to the relative analysis of multiple ECochG signals recorded from different locations in combination with positional information to monitor the acoustic response of the inner ear. Figures 6A-6F It will be appreciated that the above uses only relative analysis of multiple ECochG signals to facilitate an overall understanding of the technology presented herein, and that various aspects of the technology presented herein may be implemented using ECochG signals recorded from a single site in combination with positional information to monitor the acoustic response of the inner ear.

[0088] For example, the extension Figures 8A-8C In embodiments of the present invention, aspects of the technology presented herein may record or monitor only the cochlear microphonic potential magnitude recorded from the primary recording site (e.g., record or monitor only the signal 833, without recording or at least monitoring the signal 831). In other words, these embodiments will operate similarly to those described above, but may not record the signal from the second recording site, or record the signal from the second recording site but do not analyze / monitor the signal from the second recording site. In practice, the system will monitor to detect a decrease in the cochlear microphonic potential magnitude 833 recorded from a single fixed inner ear position (i.e., placing a fixed electrode at the primary recording site). The decrease in the cochlear microphonic potential magnitude 833 can be used to determine a change in the acoustic response of the inner ear.

[0089] As pointed out, Figures 6A-6F, 7A-7C, and 8A-8C show techniques where the secondary recording site is fixed at the tip electrode and the primary recording site is a fixed position (e.g., angular insertion depth) relative to the cochlea 127 (e.g., the electrode used at the primary recording site changes over time, while the position of the primary recording site remains substantially fixed / constant). According to other embodiments, the secondary recording site is fixed at the tip electrode and the primary recording site is fixed at a different electrode, which means that the position of the primary recording site relative to the cochlea changes over time.

[0090] More specifically, according to these embodiments, an acoustic stimulus 187 (e.g., a 500 Hertz (Hz) tone) is delivered to the cochlea 127, and a recording module 188 records a voltage trace of at least a few milliseconds of the acoustically evoked response (ECochG signal) at a secondary recording site (i.e., the topmost electrode contact) As noted, the secondary recording site and the primary recording site are fixed relative to the stimulation assembly 116, and move relative to the cochlea 127 as the stimulation assembly is advanced into the cochlea.

[0091] When the stimulation assembly 116 is inserted, the ECochG insertion monitoring system 180 continuously estimates the position of the stimulation assembly 116 relative to the cochlea (e.g., the position of the secondary recording site and the primary recording site). For example, the ECochG insertion monitoring system 180 can determine the angular insertion depth of each electrode contact inside the cochlea at least twice per second, and optionally also determine the position of the electrode contact at each angle or in a cross-sectional plane of the cochlear bend in a cylindrical coordinate system or other three-dimensional coordinate system. The ECochG insertion monitoring system 180 records the acoustic evoked response and the position corresponding to each site at the time of recording.

[0092] In these examples, the ECochG insertion monitoring system 180 operates by comparing the magnitude of acoustics induced at nearby locations over time. A nearby location can be, for example, a Euclidean distance less than or equal to half the distance of the electrode spacing (e.g., 0.375 mm). If the difference or ratio of the acoustically induced response at a location decreases from the maximum response at that location by more than a limit, for example, 30% or less, then a significant drop is determined to exist at that location.

[0093] Fig.9A , 9B 9C schematically illustrate exemplary monitoring parameters of an ECochG signal obtained during an exemplary insertion of the stimulation assembly 116 into the cochlea 127, wherein the secondary recording site and the primary recording site are each affixed to an electrode contact. More specifically, Fig.9A Included is a trace / line 931 representing the amplitude / magnitude of the cochlear microphonic potential (CM) recorded from a second recording site (i.e., the top-most electrode contact), and a line 937 representing the magnitude of the cochlear microphonic potential from a second electrode contact positioned 3 mm toward the bottom of the top-most contact.

[0094] Fig. 9B Included is a line 935 representing the angular insertion depth (AID) of the most distal electrode contact in the entire insertion, and a line 943 representing the angular insertion depth of the other electrode contacts corresponding to the primary recording site. Fig. 9C Included is line 945, which represents the ratio change in decibels (dB) of the cochlear microphonic potential magnitude recorded from the more distal electrode contact (primary recording site) to the cochlear microphonic potential magnitude previously recorded from the most distal contact at the same cochlear location (e.g., substantially the same insertion depth). Note that in these examples, the cochlear microphonic potential ratio is stable and indicates that there was no interference with acoustic hearing during this insertion period and that the cochlear microphonic potential magnitude observed at the apical electrode is due to local anatomy.

[0095] Fig. 10A , 10B 10C schematically illustrates exemplary monitoring parameters of an ECochG signal obtained during another exemplary insertion of the stimulation assembly 116 into the cochlea 127, wherein the secondary recording site and the primary recording site are each fixed to an electrode contact. More specifically, Fig. 10A Included is a trace / line 1031 representing the amplitude / magnitude of the cochlear microphonic potential (CM) recorded from a second recording site (i.e., the top-most electrode contact), and a line 1037 representing the magnitude of the cochlear microphonic potential from a second electrode contact positioned 3 mm basally from the top-most contact.

[0096] Fig. 10B Included are line 1035 representing the angular insertion depth (AID) of the most distal electrode contact in the entire insertion, and line 1043 representing the angular insertion depth of the other electrode contacts corresponding to the primary recording site. Fig. 10C Included is line 1045, which represents the change in the ratio of the cochlear microphonic potential magnitude recorded from the lower electrode contact (primary recording site) to the cochlear microphonic potential magnitude previously recorded from the most apical contact at the same cochlear location, in dB. In these examples, the cochlear microphonic potential ratio is stable until a time of approximately 120 seconds, at which time the cochlear microphonic potential ratio suddenly drops. This indicates a significant disturbance in acoustic hearing during insertion at approximately 120 seconds, and an earlier drop in the cochlear microphonic potential magnitude from the most apical electrode contact at 100 seconds (lines 1031, Fig. 10A ) is due to the local cochlear anatomy. Figures 10A-10C In the example of , when significant interference with acoustic hearing is detected, the ECochG insertion monitoring system 180 generates an output to initiate corrective action (e.g., issuing a notification or warning, providing a recommendation to a surgeon, etc.).

[0097] As noted above, when a recording of the ECochG signal is generated, the position of the electrode contacts within the cochlea is estimated and associated with the recorded ECochG signal. In other words, a recording of the ECochG signal from a secondary recording site or a primary recording site will include: (1) a recorded ECochG signal (e.g., cochlear microphonic potentials, cochlear sum potentials, and auditory nerve neural sounds, etc. measured independently or in various combinations) and (2) an estimated position of the electrode contacts when the ECochG signal was recorded. The ECochG signal recorded from the cochlea and the estimated electrode position are collectively referred to as "ECochG signal data." In some embodiments, each record of the ECochG signal may also include time information (e.g., a timestamp) when the ECochG signal was recorded, and this time information may be included in the ECochG signal data.

[0098] Many different techniques may be used to estimate / determine the location of the electrode contacts. For example, the location of the electrode contacts (e.g., angular insertion depth) may be estimated based on visual tracking (visual markings on the surgical microscope and / or stimulation assembly 116), video of the insertion site, fluoroscopy, or other imaging modalities, based on data captured during robotic insertion or another insertion with sensors tracking the length of the stimulation assembly inserted into the cochlea, and / or data derived from electrical measurements obtained from the stimulation assembly 116 (e.g., changes in electrical impedance when the electrode contacts move from a non-conductive medium such as air to a conductive medium such as perilymph). The one or more electrical measurements may include one or more impedance measurements, such as a four-point impedance measurement. A four-point impedance measurement may involve passing a current between two electrode contacts and measuring the impedance induced between a pair of inner electrode contacts. Other impedance measurements may include transimpedance measurements, two-point impedance measurements, and the like. In some examples, one or more electrical measurements may collect an ECochG signal or neural response and use this data (e.g., analysis of the phase / delay of the ECochG signal) to, for example, determine an optimal frequency or characteristic frequency for recording, electrode contact location, and the like.

[0099] In some examples, if the position of one electrode is determined, the system may estimate the position of other electrode contacts. For example, in some such embodiments, the technology may use multiple intraoperatively collected electrical measurements, such as impedance measurements (e.g., CG, MP1, MP2, and MP12), transimpedance metrics (TIM), and intracochlear bipolar impedance, in combination with intraoperative CT imaging or postoperative CT imaging, to identify the relationship between electrical measurements and / or their characteristics to determine the position of electrode contacts inside the cochlea. For example, the relationship between electrical measurements and / or their characteristics may be used in combination with a model and / or algorithm (e.g., a statistical model, a probability model, a first principle model, etc.) used to estimate the real-time position of the electrode of the stimulation component inside the cochlea of ​​the recipient. In these embodiments, electrical measurements may be acquired, processed, and input into a model and / or algorithm to estimate the position of the electrode. As used herein, the position of the electrode contact may include a position relative to the modiolus (e.g., modiolus proximity), an insertion angle, an insertion distance from the mid-modiolus axis, or other information about the placement or position of one or more parts of the electrode array. Additional details regarding techniques for estimating electrode contact location are described in U.S. Provisional Application No. 63 / 277,253, filed on November 9, 2021, the contents of which are hereby incorporated herein by reference.

[0100] As noted, the position of the electrode may include position relative to the modiolus (eg, modiolus proximity), insertion angle, distance from the mid-modiolus axis, or other information regarding the placement or position of one or more portions of the electrode array. Fig.11 1 is a cross-sectional view of the cochlea 127 with the stimulation assembly 127 in the scala tympani 129. In this cross-section, the stimulation assembly 127 is very close to the organ of Corti 151 and the outer hair cells (OHC) 153, and therefore, for this cross-section of the cochlea (at a specific angle / depth), the cochlear microphonic potential magnitude is at its maximum. If the stimulation assembly 127 is farther from this position later, medially, or inferiorly (as indicated by the three arrows 1147) in the same cross-section, the cochlear microphonic potential magnitude is expected to decrease with distance from the OHC. According to the techniques presented herein, knowledge of the three-dimensional position of the electrode contacts to the scala tympani can be used to compensate or correct for these different positions.

[0101] The above examples have been described with reference to using one acoustic stimulus during the insertion process. In some embodiments, multiple different acoustic stimuli, for example, of different frequencies, may also be used during the insertion process. For example, in an embodiment using a main recording site with a fixed position relative to the cochlea, the system may record an ECochG signal induced by an acoustic stimulus associated with a nominal target frequency (e.g., a fixed low frequency, such as 500 Hz) and a frequency that is optimal for the fixed position (based on an estimate at this fixed position or the best response determined first). In an embodiment where the second recording site and the main recording site are each fixed at the electrode contact, the system may record an ECochG signal induced by an acoustic stimulus associated with a nominal target frequency (e.g., a fixed low frequency, such as 500 Hz) and a second frequency that varies / changes according to the insertion depth. For example, the second frequency may be a frequency that varies over time so as to become a frequency associated with a pure tone region position (tonotopic place) between two recording electrodes. These techniques may record an ECochG signal induced by one or more additional acoustic stimuli (e.g., an acoustic stimulus with a varying frequency) so as to remain only at the bottom of the main recording site.

[0102] As noted above, the techniques presented herein can provide surgeons or other users with an understanding of the ECochG signals of surgical records and the impact on the surgeon. That is, the ECochG insertion monitoring system 180 is configured to automatically analyze the ECochG signal data and provide the surgeon and other users with guidance on when to perform surgical intervention to maximize / balance hearing preservation and electrode insertion depth (e.g., provide the surgeon with information to guide its decision-making process and maximize the preservation of residual hearing and overall outcome).

[0103] In one example, the ECochG insertion monitoring system 180 is configured such that an alarm / warning is generated when the system detects a significant disturbance in acoustic hearing, but no alarm is provided when the system determines that the change in cochlear microphonic potential magnitude is due to local anatomy. In a specific example, if the stimulation assembly is retracted to a point where the magnitude of the cochlear microphonic potential was previously lower, the system does not issue an alarm. Similarly, if the surgeon withdraws the stimulation assembly to recover from a dip, and the location of the peak response is passed, the system takes the new location into account when determining whether the dip has recovered.

[0104] As previously mentioned, the technology disclosed herein can be applied to any of a variety of situations and used with a variety of different devices. For example, Fig.12An exemplary vestibular stimulator is shown that can be used to implement various aspects of the technology presented herein. The technology of the present disclosure can be applied to other medical devices, such as neurostimulators, pacemakers, defibrillators, sleep apnea management stimulators, epilepsy treatment stimulators, tinnitus management stimulators and vestibular stimulation devices, as well as other medical devices that deliver stimulation to tissues. These various systems and devices can benefit from the technology described herein.

[0105] As pointed out, Fig.12 An exemplary vestibular stimulator system 1202 is shown, which can be used to implement the embodiments presented herein. As shown, the vestibular stimulator system 1202 includes an implantable component (vestibular stimulator) 1212 and an external device / component 1204 (e.g., an external processing device, a battery charger, a remote controller, etc.). The external device 1204 includes a transceiver unit 1260. In this way, the external device 1204 is configured to transmit data (and possible power) to the vestibular stimulator 1212. An ECochG insertion monitoring system 1280 is also shown.

[0106] The vestibular stimulator 1212 includes an implant body (main module) 1234, a lead region 1236, and a stimulation assembly 1216, all configured to be implanted beneath the skin / tissue (tissue) 1215 of a recipient. The implant body 1234 generally includes an airtight sealed housing 1238 in which an RF interface circuit system, one or more rechargeable batteries, one or more processors, and a stimulator unit are disposed. The implant body 134 also includes an internal / implantable coil 1214, which is generally external to the housing 1238 but connected to a transceiver via an airtight feedthrough (not shown).

[0107] Stimulation assembly 1216 includes a plurality of electrode contacts 1244(1)-(3) disposed in a carrier member (e.g., a flexible silicone body). In this particular example, stimulation assembly 1216 includes three (3) stimulation electrode contacts, referred to as stimulation electrode contacts 1244(1), 1244(2), and 1244(3). Stimulation electrode contacts 1244(1), 1244(2), and 1244(3) serve as an electrical interface for delivering electrical stimulation signals to the vestibular system of a recipient.

[0108] The stimulation assembly 1216 is configured so that a surgeon can implant the stimulation assembly near the recipient's otolith organ via, for example, the recipient's oval window. It should be appreciated that this particular embodiment with three stimulation electrode contacts is merely illustrative, and the techniques presented herein can be used with stimulation assemblies having different numbers of stimulation electrode contacts, stimulation assemblies having different lengths, etc.

[0109] As pointed out, Fig.12. The ECochG insertion monitoring system 1280 can be configured to implement the above-described techniques to monitor the insertion of the stimulation assembly 1216 into the inner ear of the recipient (e.g., to obtain and analyze ECochG signal data during the insertion of the stimulation assembly 1216). Fig.12 In embodiments of the present invention, the vestibular system may be stimulated not based on acoustic sounds, but rather based on, for example, low frequency vibrations, motion data (e.g., linear or rotational acceleration signals), or other signals that may induce ECochG signals from the vestibular system.

[0110] Fig.13 13 is a flow chart of an exemplary method 1390 for inserting a stimulation assembly including a plurality of electrode contacts into an inner ear of a recipient according to certain embodiments presented herein. The method 1390 begins at 1392, where an ECochG insertion monitoring system (e.g., ECochG insertion monitoring system 180, 1280, etc.) repeatedly records a first ECochG signal from a primary recording site over a period of time. At 1394, the ECochG insertion monitoring system obtains position information of the primary recording site associated with the recording of the first ECochG signal. At 1396, the ECochG insertion monitoring system uses the position information of the primary recording site to analyze the first ECochG signal.

[0111] In certain embodiments, Fig.13 The method 1390 also includes repeatedly recording a second ECochG signal from a second recording site during the time period, and obtaining position information of the second recording site associated with the recording of the second ECochG signal. In these examples, the first ECochG signal is analyzed relative to the second ECochG signal using the position information of each of the primary recording site and the second recording site.

[0112] Fig.14 1490 is a flowchart of a method 1490 according to certain embodiments presented herein. Method 1490 begins at 1492, where an ECochG insertion monitoring system (e.g., ECochG insertion monitoring system 180, 1280, etc.) repeatedly delivers at least one acoustic stimulus to the inner ear of a recipient during insertion of a stimulation assembly into the inner ear, wherein the stimulation assembly includes a plurality of electrode contacts. At 1494, the ECochG insertion monitoring system records a first electrocochlear graph (ECochG) signal induced in response to the delivery of at least one acoustic stimulus at a primary recording site. At 1496, the ECochG insertion monitoring system records position information of one or more portions of the stimulation assembly during monitoring of the first ECochG signal. At 1498, the ECochG insertion monitoring system monitors the acoustic response of the inner ear based at least on the first ECochG signal and the position information.

[0113] It should be understood that although specific uses of the present technology have been illustrated and discussed above, the disclosed technology can be used with various devices according to many examples of the present technology. The above discussion is not intended to indicate that the disclosed technology is only suitable for implementation in systems similar to those shown in the accompanying drawings. In general, additional configurations can be used to practice the processes and systems herein, and / or some aspects described can be excluded without departing from the processes and systems disclosed herein.

[0114] The present disclosure describes some aspects of the present invention technology with reference to the accompanying drawings, in which only some possible aspects are shown. However, other aspects may be embodied in many different forms and should not be construed as being limited to the aspects set forth herein. Instead, these aspects are provided to make the present disclosure detailed and complete and to fully convey the scope of possible aspects to those skilled in the art.

[0115] It should be understood that the various aspects (e.g., parts, components, etc.) described herein with respect to the figures are not intended to limit the systems and processes to the specific aspects described. Therefore, additional configurations can be used to practice the methods and systems herein, and / or some aspects described can be excluded without departing from the methods and systems disclosed herein.

[0116] According to certain aspects, a system and a non-transitory computer-readable storage medium are provided. The system is configured with hardware, and the hardware is configured to perform operations similar to the method of the present disclosure. One or more non-transitory computer-readable storage media include instructions, and the instructions, when executed by one or more processors, cause the one or more processors to perform operations similar to the method of the present disclosure.

[0117] Similarly, where steps of a process are disclosed, these steps are described for the purpose of illustrating the present methods and systems, and are not intended to limit the present disclosure to a particular sequence of steps. For example, the steps may be performed in a different order, two or more steps may be performed simultaneously, additional steps may be performed, and disclosed steps may be eliminated without departing from the present disclosure. Furthermore, the disclosed processes may be repeated.

[0118] Although specific aspects are described herein, the scope of the present technology is not limited to these specific aspects. Those skilled in the art will recognize other aspects or improvements within the scope of the present technology. Therefore, specific structures, actions or media are disclosed only as illustrative aspects. The scope of the present technology is limited by the following claims and any equivalents therein.

[0119] It should also be understood that the embodiments presented herein are not mutually exclusive and that various embodiments can be combined with another embodiment in any of a variety of different ways.

Claims

1. A method for inserting a stimulation assembly comprising a plurality of electrode contacts into an inner ear of a recipient, comprising: Repeatedly recording the first electrocochlear graph (ECochG) signal from the primary recording site over a certain period of time; obtaining location information of the primary recording site associated with recording of the first ECochG signal; and The first ECochG signal is analyzed using at least the positional information of the primary recording site.

2. The method according to claim 1, further comprising: repeatedly recording a second ECochG signal from a second recording site during the time period; obtaining location information of the second recording site associated with recording of the second ECochG signal; and Using the position information of each of the primary recording site and the second recording site, the first ECochG signal is analyzed relative to the second ECochG signal.

3. The method according to claim 1 or 2, wherein repeatedly recording the second ECochG signal from the second recording site during the time period comprises: repeatedly recording the second ECochG signal via the first electrode at a plurality of different locations within the inner ear, The second recording site is fixed at the first electrode.

4. The method of claim 3, wherein repeatedly recording the second ECochG signal via the first electrode at the plurality of different locations within the inner ear comprises: The second ECochG signal is repeatedly recorded at the plurality of different locations within the inner ear via a topmost electrode contact of the plurality of electrode contacts.

5. The method of claim 4, wherein repeatedly recording the first ECochG signal from the primary recording site during the time period comprises: The first ECochG signal is repeatedly recorded at a substantially fixed target location within the inner ear via a series of different electrode contacts of the plurality of electrode contacts.

6. The method of claim 5, wherein analyzing the first ECochG signal relative to the second ECochG signal using the position information of each of the primary recording site and at least one second recording site comprises: detecting a decrease in a parameter of the second ECochG signal recorded from the first electrode; as well as A determination is made as to whether the decrease in the parameter of the second ECochG signal is accompanied by a corresponding decrease in the same parameter of the first ECochG signal recorded at the substantially fixed target location via one or more electrode contacts of the series of different electrode contacts.

7. The method according to claim 6, further comprising: A determination is made as to whether the drop in the parameter of the second ECochG signal and the corresponding drop in the same parameter of the first ECochG signal recorded at the substantially fixed target location each exceed a predetermined limit.

8. The method according to claim 6, further comprising: determining that a decrease in the parameter of the second ECochG signal is accompanied by a corresponding decrease in the same parameter of the first ECochG signal recorded at the substantially fixed target location via one or more of the series of different electrode contacts; as well as In response to determining that a decrease in the parameter of the second ECochG signal is accompanied by a corresponding decrease in the same parameter of the first ECochG signal, an output is generated to initiate corrective action.

9. The method of claim 1 or 2, wherein analyzing the first ECochG signal using at least the position information of each of the primary recording sites comprises: The first ECochG signal is monitored for a predetermined change in a parameter of the first ECochG signal.

10. The method of claim 9, wherein monitoring the first ECochG signal for a predetermined change in a parameter of the first ECochG signal comprises: The first ECochG signal is monitored for changes in the parameter exceeding a predetermined limit.

11. The method of claim 1 or 2, wherein repeatedly recording the first ECochG signal from the primary recording site during the time period comprises: repeatedly recording the first ECochG signal via a second electrode at a plurality of different locations within the inner ear, The main recording site is fixed at the second electrode.

12. The method of claim 11, wherein analyzing the second ECochG signal relative to the first ECochG signal using the position information of each of the second recording site and at least one main recording site comprises: generating a reference value correlating a parameter of the second ECochG signal with a parameter of the first ECochG signal during the time period; as well as The reference value is monitored to detect when the reference value drops by an amount exceeding a predetermined limit value.

13. The method according to claim 12, further comprising: determining an amount by which the reference value decreases beyond the predetermined limit value; as well as In response to determining that the reference value has dropped by an amount exceeding the predetermined limit value, an output is generated to initiate corrective action.

14. The method of claim 12, wherein generating a reference value correlating the parameter of the second ECochG signal with the parameter of the first ECochG signal during the time period comprises: A ratio of the parameter of the second ECochG signal to the parameter of the first ECochG signal during the time period is calculated.

15. The method according to claim 1 or 2, further comprising: Time information for the recording of the second ECochG signal and the recording of the first ECochG signal is obtained.

16. The method according to claim 15, further comprising: The second ECochG signal is analyzed relative to the first ECochG signal using the position information of each of the second recording site and at least one main recording site and the time information.

17. The method according to claim 1 or 2, wherein obtaining the position information of the second recording location and the main recording location respectively associated with the recording of the second ECochG signal and the recording of the first ECochG signal comprises: An angular insertion depth of one or more electrodes of a plurality of electrodes is estimated when recording the second ECochG signal or the first ECochG signal.

18. The method according to claim 1 or 2, wherein obtaining the position information of the second recording location and the main recording location respectively associated with the recording of the second ECochG signal and the recording of the first ECochG signal further comprises: The proximity of one or more electrodes of a plurality of electrodes to a wall of the inner ear is estimated when recording the second ECochG signal or the first ECochG signal.

19. The method of claim 1 or 2, wherein analyzing the second ECochG signal relative to the first ECochG signal using the position information of each of the second recording site and at least one main recording site comprises: Properties of cochlear microphonic potentials associated with the second ECochG signal are analyzed relative to properties of cochlear microphonic potentials associated with the first ECochG signal.

20. The method of claim 19, wherein the property of the cochlear microphonic potential associated with the second ECochG signal and the property of the cochlear microphonic potential associated with the first ECochG signal are cochlear microphonic potential magnitudes.

21. The method of claim 1 or 2, wherein analyzing the second ECochG signal relative to the first ECochG signal using the position information of each of the second recording site and at least one main recording site comprises: Properties of the cochlear sum potential associated with the second ECochG signal are analyzed relative to properties of the cochlear sum potential associated with the first ECochG signal.

22. The method of claim 1 or 2, wherein analyzing the second ECochG signal relative to the first ECochG signal using the position information of each of the second recording site and at least one main recording site comprises: Properties of the auditory nerve neural tones associated with the second ECochG signal are analyzed relative to properties of the auditory nerve neural tones associated with the first ECochG signal.

23. The method of claim 1 or 2, wherein analyzing the second ECochG signal relative to the first ECochG signal using the position information of each of the second recording site and at least one main recording site comprises: determining a change in an acoustic response of the cochlea based on the second ECochG signal, the first ECochG signal, and the position information; as well as In response to determining a change in the acoustic response of the cochlea, an output is generated to initiate corrective action.

24. The method of claim 23, wherein generating an output to initiate corrective action comprises: At least one of an audible warning, a visual warning, or a tactile warning is generated.

25. The method of claim 23, wherein generating an output to initiate corrective action comprises: determining said corrective action to be initiated; as well as A control signal indicative of the corrective action is generated.

26. The method of claim 23, wherein generating an output to initiate corrective action comprises: A recommendation is generated for the corrective action to be initiated.

27. A method comprising: repeatedly delivering at least one acoustic stimulus to the inner ear of a recipient during insertion of a stimulation assembly into the inner ear, wherein the stimulation assembly comprises a plurality of electrode contacts; recording, at a primary recording site, a first electrocochlear graph (ECochG) signal evoked in response to delivering the at least one acoustic stimulus; recording position information of one or more parts of the stimulation assembly during monitoring of the first ECochG signal; as well as An acoustic response of the inner ear is monitored based at least on the first ECochG signal and the position information.

28. The method according to claim 27, further comprising: recording, at a second recording site, a second ECochG signal evoked in response to delivering the at least one acoustic stimulus; as well as The acoustic response of the inner ear is monitored based on the first ECochG signal, the second ECochG signal, and the position information.

29. The method of claim 27 or 28, wherein recording the second ECochG signal evoked in response to delivering the at least one acoustic stimulus comprises: repeatedly recording the second ECochG signal via the first electrode at a plurality of different locations within the inner ear, The second recording site is fixed at the first electrode.

30. The method of claim 29, wherein repeatedly recording the second ECochG signal via the first electrode at the plurality of different locations within the inner ear comprises: The second ECochG signal is repeatedly recorded at the plurality of different locations within the inner ear via a topmost electrode contact of the plurality of electrode contacts.

31. The method of claim 30, wherein recording the first ECochG signal at the primary recording site comprises: The first ECochG signal is repeatedly recorded at a substantially fixed target location within the inner ear via a series of different electrode contacts of the plurality of electrode contacts.

32. The method of claim 31 , monitoring the acoustic response of the inner ear based on the first ECochG signal, the second ECochG signal, and the position information comprises: detecting a decrease in a parameter of the second ECochG signal recorded from the first electrode; as well as A determination is made as to whether the decrease in the parameter of the second ECochG signal is accompanied by a corresponding decrease in the same parameter of the first ECochG signal recorded at the substantially fixed target location via one or more electrode contacts of the series of different electrode contacts.

33. The method of claim 32, further comprising: A determination is made as to whether the drop in the parameter of the second ECochG signal and the corresponding drop in the same parameter of the first ECochG signal recorded at the substantially fixed target location each exceed a predetermined limit.

34. The method of claim 32, further comprising: determining that a decrease in the parameter of the second ECochG signal is accompanied by a corresponding decrease in the same parameter of the first ECochG signal recorded at the substantially fixed target location via one or more of the series of different electrode contacts; as well as In response to determining that a decrease in the parameter of the second ECochG signal is accompanied by a corresponding decrease in the same parameter of the first ECochG signal, an output is generated to initiate corrective action.

35. The method of claim 27 or 28, wherein monitoring the acoustic response of the inner ear based on the first ECochG signal and the position information comprises: The first ECochG signal is monitored for a predetermined change in a parameter of the first ECochG signal.

36. The method of claim 35, wherein monitoring the first ECochG signal for a predetermined change in a parameter of the first ECochG signal comprises: The first ECochG signal is monitored for changes in the parameter exceeding a predetermined limit.

37. The method of claim 27 or 28, wherein recording the first ECochG signal from the primary recording site comprises: repeatedly recording the first ECochG signal via a second electrode at a plurality of different locations within the inner ear, The main recording site is fixed at the second electrode.

38. The method of claim 37, wherein monitoring the acoustic response of the inner ear based on the first ECochG signal, the second ECochG signal, and the position information comprises: generating a reference value correlating a parameter of the second ECochG signal with a parameter of the first ECochG signal within a certain time period; as well as The reference value is monitored to detect when the reference value drops by an amount exceeding a predetermined limit value.

39. The method of claim 38, further comprising: determining an amount by which the reference value decreases beyond the predetermined limit value; as well as In response to determining that the reference value has dropped by an amount exceeding the predetermined limit value, an output is generated to initiate corrective action.

40. The method of claim 38, wherein generating a reference value relating the parameter of the second ECochG signal to the parameter of the first ECochG signal over the time period comprises: A ratio of the parameter of the second ECochG signal to the parameter of the first ECochG signal during the time period is calculated.

41. The method according to claim 27 or 28, further comprising: Time information for the recording of the second ECochG signal and the recording of the first ECochG signal is obtained.

42. The method of claim 41 further comprising: The second ECochG signal is analyzed relative to the first ECochG signal using the position information and the time information.

43. The method of claim 27 or 28, wherein recording position information of one or more portions of the stimulation assembly during monitoring of the first ECochG signal comprises: An angular insertion depth of one or more portions of the stimulation assembly is estimated while recording the first ECochG signal.

44. The method of claim 27 or 28, wherein recording position information of one or more portions of the stimulation assembly during monitoring of the first ECochG signal comprises: The proximity of one or more portions of the stimulation assembly to a wall of the inner ear is estimated while recording the first ECochG signal.

45. The method of claim 27 or 28, wherein monitoring the acoustic response of the inner ear based on the first ECochG signal, the second ECochG signal, and the position information comprises: Properties of cochlear microphonic potentials associated with the second ECochG signal are analyzed relative to properties of cochlear microphonic potentials associated with the first ECochG signal.

46. ​​The method of claim 45, wherein the property of the cochlear microphonic potential associated with the second ECochG signal and the property of the cochlear microphonic potential associated with the first ECochG signal are cochlear microphonic potential magnitudes.

47. The method of claim 27 or 28, wherein monitoring the acoustic response of the inner ear based on the first ECochG signal, the second ECochG signal, and the position information comprises: Properties of the cochlear sum potential associated with the second ECochG signal are analyzed relative to properties of the cochlear sum potential associated with the first ECochG signal.

48. The method of claim 27 or 28, wherein monitoring the acoustic response of the inner ear based on the first ECochG signal, the second ECochG signal, and the position information comprises: Properties of the auditory nerve neural tones associated with the second ECochG signal are analyzed relative to properties of the auditory nerve neural tones associated with the first ECochG signal.

49. The method according to claim 27 or 28, further comprising: determining changes in the acoustic response of the inner ear; as well as In response to determining a change in the acoustic response of the inner ear, an output is generated to initiate corrective action.

50. The method of claim 49, wherein generating an output to initiate corrective action comprises: At least one of an audible warning, a visual warning, or a tactile warning is generated.

51. The method of claim 49, wherein generating an output to initiate corrective action comprises: determining said corrective action to be initiated; as well as A control signal indicative of the corrective action is generated.

52. The method of claim 49, wherein generating an output to initiate corrective action comprises: A recommendation is generated for the corrective action to be initiated.

53. One or more non-transitory computer-readable storage media comprising instructions that, when executed by a processor, cause the processor to: obtaining a second electrocochlear (ECochG) signal repeatedly recorded via a tip electrode of the stimulation assembly during insertion of the stimulation assembly into the recipient's inner ear; obtaining a first ECochG signal repeatedly recorded via at least one other electrode of the stimulation assembly during insertion of the stimulation assembly into the inner ear; and The second ECochG signal recorded via the tip electrode is analyzed relative to the first ECochG signal recorded via at least one other electrode to characterize an acoustic response of the inner ear.

54. The one or more non-transitory computer-readable storage media of claim 53, wherein the instructions that, when executed by the processor, cause the processor to analyze the second ECochG signal relative to the first ECochG signal to characterize an acoustic response of the inner ear include instructions that, when executed, cause the processor to: It is determined whether a change in the second ECochG signal is caused by a change in local anatomy as the stimulation assembly moves through the inner ear, or whether the change in the second ECochG signal is caused by a change in the acoustic response of the inner ear.

55. The one or more non-transitory computer-readable storage media of claim 53, further comprising instructions that, when executed by the processor, cause the processor to: obtaining position information recorded for one or more portions of the stimulation assembly during recording of the first ECochG signal and the second ECochG signal; and The acoustic response of the inner ear is also characterized based on the position information.

56. The one or more non-transitory computer-readable storage media of claim 53, 54, or 55, wherein the instructions that, when executed by the processor, cause the processor to analyze the second ECochG signal relative to the first ECochG signal to characterize an acoustic response of the inner ear include instructions that, when executed, cause the processor to: detecting a decrease in a parameter of the second ECochG signal recorded from the apical electrode; and A determination is made as to whether the drop in the parameter of the second ECochG signal is accompanied by a corresponding drop in the same parameter of the first ECochG signal.

57. The one or more non-transitory computer-readable storage media of claim 56, further comprising instructions that, when executed by the processor, cause the processor to: A determination is made as to whether the drop in the parameter of the second ECochG signal and the corresponding drop in the same parameter of the first ECochG signal each exceed a predetermined limit.

58. The one or more non-transitory computer-readable storage media of claim 53, 54, or 55, wherein the instructions that, when executed by the processor, cause the processor to analyze the second ECochG signal relative to the first ECochG signal to characterize an acoustic response of the inner ear include instructions that, when executed, cause the processor to: generating a reference value correlating a parameter of the second ECochG signal with a parameter of the first ECochG signal; and The reference value is monitored to detect when the reference value drops by an amount exceeding a predetermined limit value.

59. The one or more non-transitory computer-readable storage media of claim 58, further comprising instructions that, when executed by the processor, cause the processor to: determining an amount by which the reference value drops beyond the predetermined limit value; and In response to determining that the reference value has dropped by an amount exceeding the predetermined limit value, an output is generated to initiate corrective action.

60. The one or more non-transitory computer-readable storage media of claim 53, 54, or 55, further comprising instructions that, when executed by the processor, cause the processor to: obtaining time information for recording of the second ECochG signal and recording of the first ECochG signal; and Using the time information, the second ECochG signal is analyzed relative to the first ECochG signal.

61. The one or more non-transitory computer-readable storage media of claim 53, 54, or 55, further comprising instructions that, when executed by the processor, cause the processor to: determining a change in an acoustic response of the inner ear; and In response to determining a change in the acoustic response of the inner ear, an output is generated to initiate corrective action.

62. The one or more non-transitory computer-readable storage media of claim 61, wherein the instructions that, when executed by the processor, cause the processor to generate an output to initiate corrective action include instructions that, when executed, cause the processor to: At least one of an audible warning, a visual warning, or a tactile warning is generated.

63. The one or more non-transitory computer-readable storage media of claim 61, wherein the instructions that, when executed by the processor, cause the processor to generate an output to initiate corrective action include instructions that, when executed, cause the processor to: determining said corrective action to be initiated; and A control signal indicative of the corrective action is generated.

64. The one or more non-transitory computer-readable storage media of claim 61, wherein the instructions that, when executed by the processor, cause the processor to generate an output to initiate corrective action include instructions that, when executed, cause the processor to: A recommendation is generated for the corrective action to be initiated.

65. A system comprising: User interface; a network interface for communicating with an implantable medical device comprising a plurality of electrode contacts configured to be implanted in a recipient; Memory; as well as One or more processors configured to: obtaining a recording of a first electrocochlear graph (ECochG) signal from a primary recording site during implantation of the plurality of electrode contacts in the recipient; determining location information of the primary recording site associated with the recording of the first ECochG signal; and The recording of the first ECochG signal is analyzed using at least the position information.

66. The system of claim 65, wherein the one or more processors are configured to: obtaining a recording of a second ECochG signal from a second recording site during implantation of the plurality of electrode contacts in the recipient; determining location information of the second recording location associated with the recording of the second ECochG signal; and Using the position information of each of the primary recording site and the second recording site, the first ECochG signal is analyzed relative to the second ECochG signal.

67. The system of claim 65 or 66, wherein to determine position information of the second recording site and the main recording site associated with the recording of the second ECochG signal and the recording of the first ECochG signal, respectively, the one or more processors are configured to: An angular insertion depth of one or more electrodes of a plurality of electrodes is estimated when recording the second ECochG signal or the first ECochG signal.

68. The system of claim 65 or 66, wherein to determine location information of the second recording location and the primary recording location associated with the recording of the second ECochG signal and the recording of the first ECochG signal, respectively, the one or more processors are configured to: The proximity of one or more electrodes of a plurality of electrodes to a wall of the inner ear is estimated when recording the second ECochG signal or the first ECochG signal.

69. The system of claim 65 or 66, wherein to analyze the second ECochG signal relative to the first ECochG signal using the position information of each of the second recording site and at least one primary recording site, the one or more processors are configured to: Properties of cochlear microphonic potentials associated with the second ECochG signal are analyzed relative to properties of cochlear microphonic potentials associated with the first ECochG signal.

70. The system of claim 65 or 66, wherein to analyze the second ECochG signal relative to the first ECochG signal using the position information of each of the second recording site and at least one primary recording site, the one or more processors are configured to: Properties of the cochlear sum potential associated with the second ECochG signal are analyzed relative to properties of the cochlear sum potential associated with the first ECochG signal.

71. The system of claim 65 or 66, wherein to analyze the second ECochG signal relative to the first ECochG signal using the position information of each of the second recording site and at least one primary recording site, the one or more processors are configured to: Properties of the auditory nerve neural tones associated with the second ECochG signal are analyzed relative to properties of the auditory nerve neural tones associated with the first ECochG signal.

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