System and method for detecting perturbed basal membrane wave propagation

Abstract

The invention relates to a system and method for detecting disturbed basilar membrane wave propagation and to a system for monitoring the insertion of electrodes into a patient with residual hearing. Electrocochleography (ECochG) signals are measured on a subset of electrode contacts located in the inner ear of the patient. Two electrode contacts are selected for which the measured electrocochleography (ECochG) signals have peak amplitudes. A phase shift of the selected two electrode contacts is determined from the associated measured electrocochleography (ECochG) signals. If the phase shift between the two electrode contacts differs by more than a predetermined threshold, disturbed basilar membrane wave propagation is detected to occur in the region from the selected first electrode contact to the selected second electrode contact.

Description

Technical Field

[0001] This invention relates to systems and methods for detecting the propagation of disturbed basilar membrane waves, and to systems for monitoring the insertion of electrodes into patients with residual hearing. Background Technology

[0002] like Figure 1 As shown, a normal ear transmits sound to the tympanic membrane 102 via the outer ear 101. The tympanic membrane 102 causes movement of the ossicles (malleus, incus, and stapes) in the middle ear 103, which vibrate the oval window and round window membrane openings of the cochlea 104. The cochlea 104 is a slender cavity that spirals about two and a half times around its axis in the human cochlea. It includes a superior channel called the scala vestibulae and a inferior channel called the scala tympani, which are separated by the cochlear canal called the scala medialis and connected by the cochlear foramen. The scala tympani is separated from the scala medialis along the cochlea 104 by the basilar membrane. The basilar membrane is a major structural element and determines the mechanical wave propagation characteristics of the cochlear compartments. The axial center of the cochlea 104 is called the cochlear axis, where the spiral ganglion cells of the auditory nerve 113 reside. In response to the received sound transmitted by the middle ear 103, the fluid-filled cochlea 104 acts as a transducer to generate electrical impulses, which are sensed by the auditory nerve 113 and sent to the brain.

[0003] In some patients with some residual hearing at lower acoustic frequencies, conventional hearing aids and cochlear implants can be combined in a hybrid electroacoustic stimulation (EAS) system. The term EAS, as used in this article, is not limited to combined electroacoustic stimulation but also includes combined electrical and mechanical or vibrational stimulation. The hearing aid acoustically amplifies the lower acoustic frequencies perceived by the human ear, while the cochlear implant provides electrical stimulation at mid-to-high frequencies. See von Ilberg et al., Electric-Acoustic Stimulation of the Auditory System, ORL 61:334-340; Skarzynski et al., Preservation of Low Frequency Hearing in Partial Deafness Cochlear Implantation (PDCI) Using the Round Window Surgical Approach, Acta Otolaryngol 2007; 127:41-48; Gantz & Turner, Combining Acoustic and Electrical Speech Processing: Iowa / Nucleus Hybrid Implant, Acta Otolaryngol 2004; 124:344-347; Gstöttner et al., Hearing Preservation in Cochlear Implantation for Electric Acoustic Stimulation (Hearing Preservation in Cochlear Implantation with Acoustic Stimulation), Acta Otolaryngol 2004; 124:348-352; All of these references are incorporated herein by reference.

[0004] Figure 1Some components of a typical EAS system are also shown, including an external microphone that provides acoustic signal input to an external signal processor 111, in which two different signal processing paths are developed. Higher-frequency communication signals, containing mid-to-high frequency acoustics, are converted into a digital data format (e.g., a sequence of data frames) for transmission via a transmit coil 107 to a corresponding implanted receive coil 106 in the electrical implant 108. In addition to receiving the processed acoustic information, the electrical implant 108 performs additional signal processing, such as error correction, pulse formation, etc., and generates (based on the extracted acoustic information) an electrical stimulation pattern that is transmitted via electrode leads 109 to an implanted electrode array 110 in the scala tympani. The electrode array 110 includes multiple electrode contacts along its length on its outer surface, which provide selective electrical stimulation to the cochlea 104. The electrode contacts are typically numbered in ascending order from the tip to the rear end of the electrode assembly adjacent to the electrode leads 109, and vice versa. The external signal processor 111 also generates lower-frequency communication signals to a conventional hearing aid 105 in the ear canal, which acoustically stimulates the tympanic membrane 102, and subsequently the middle ear 103 and cochlea 104. However, the invention is not limited to the EAS system described above. For example, the EAS system can provide acoustic stimulation to the cochlea 104 in various ways, such as by using an implanted transducer attached to the ossicles in the middle ear 103, or via bone conduction with implanted or unimplanted active or passive transducers.

[0005] To achieve optimal hearing preservation outcomes in a large EAS patient population, controlled electrode array insertion is typically used to prevent trauma to the patient's cochlea. Numerous attempts have been made to improve electrode array insertion by providing real-time feedback to surgeons. This allows surgeons to make manual corrections and prevent trauma. Such a system is disclosed in the applicant's earlier patent, US9107621B2. Not only is preventing trauma important for hearing outcomes in EAS patients during electrode array insertion, but also the undisturbed cochlear mechanics for acoustic stimulation is crucial. US8630721B2 discloses an electrode array designed to preserve cochlear mechanics; however, very thin electrodes present other problems, such as kinking, and their effectiveness has not been adequately demonstrated. Instead of a thin electrode design, the inventors found that the position of the electrode array 110 within the scala tympani is most important for preserving cochlear mechanics and, therefore, for hearing outcomes in EAS patients. When the electrode array contacts the basilar membrane, the propagation of the basilar membrane (traveling wave) is disturbed, which typically causes perturbation of the cochlear mechanics. When the electrode array 110 contacts an area within the scala tympani where the basilar membrane is suspended for the same reason, cochlear mechanics also changes. Throughout this specification, the term "perturbed basilar membrane wave propagation" refers to all causes resulting from the electrode array 110 contacting an area within the scala tympani that affects the propagation of the basilar membrane (traveling wave) (i.e., affects cochlear mechanics). Therefore, it is necessary to determine whether the electrode array 110 perturbs the basilar membrane wave propagation and, if so, at what location within the scala tympani. Summary of the Invention

[0006] The present invention aims to overcome the aforementioned disadvantages of the prior art by means of the method according to claim 1, the system for detecting the propagation of disturbed basilar membrane waves according to claim 10, and the system for monitoring the insertion of an electrode array into a patient's inner ear according to claim 21. Preferred embodiments of the invention are defined in the dependent claims.

[0007] According to one aspect of the invention, a method for detecting disturbed basilar membrane wave propagation includes the following steps: In a first step, when an acoustic signal of a predetermined frequency is applied to the outer ear of a patient, electrocochlear electrogram (ECochG) signals of at least a subset of electrode contacts of an electrode array located in the inner ear of the patient are measured. In a second step, a first electrode contact and a second electrode contact are selected at least in part based on the peak amplitude of the measured ECochG signals, or alternatively at least in part based on adjacent peak amplitudes of the measured ECochG signals. In a third step, a first phase shift of the selected first electrode contact and a second phase shift of the selected second electrode contact are determined according to the associated measured ECochG signals. In a fourth step, it is determined at least in part that disturbed basilar membrane wave propagation exists in the region from the selected first electrode contact to the selected second electrode contact when the phase difference between the first and second phase shifts exceeds a predetermined threshold.

[0008] In the method according to the invention, when there is no disturbed basement membrane wave propagation, the predetermined threshold may include the phase shift between the first electrode contact and the second electrode contact, and / or the predetermined threshold may be at least 90 degrees or at least 180 degrees.

[0009] In one aspect, the method of the present invention can be used for a predetermined frequency of the acoustic signal of 500 Hz, 1000 Hz, or 2000 Hz. The predetermined frequency of the acoustic signal can be a function of the insertion position of the electrode array in the patient's inner ear. This function can be determined based on the tone localization position of the electrode array tip. The predetermined frequency of the acoustic signal can be selected as a tone localization position below or equal to an estimated region where basilar membrane wave propagation is disturbed, and the estimated region is first derived using the method of the present invention disclosed herein.

[0010] The amplitude of the acoustic signal can be at least 40 dB higher than the hearing threshold.

[0011] A system for detecting disturbed basilar membrane wave propagation according to one aspect of the invention comprises: a measuring unit for measuring electrocochlear electrograph (ECochG) signals of electrode contacts of an electrode array located in the inner ear of a patient, and a control unit. The control unit is adapted to perform the following steps: when an acoustic signal of a predetermined frequency is applied to the outer ear of a patient, measuring the ECochG signals of at least a subset of the electrode contacts of the electrode array located in the inner ear of the patient using the measuring unit. The control unit is further adapted to subsequently select a first electrode contact and a second electrode contact based at least in part on the peak amplitude of the measured ECochG signals. The control unit is further adapted to subsequently determine a first phase shift of the selected first electrode contact and a second phase shift of the selected second electrode contact based on the associated measured ECochG signals. The control unit is further adapted to determine, at least in part, that disturbed basilar membrane wave propagation exists in the region from the selected first electrode contact to the selected second electrode contact based on the condition that the phase difference between the first and second phase shifts exceeds a predetermined threshold. The control unit is further adapted to provide a signal representing the determined propagation of the disturbed basilar membrane wave.

[0012] On the other hand, the control unit can be adapted to apply a predetermined threshold, which includes the phase shift between the first and second electrode contacts, when there is no disturbed basilar membrane wave propagation. The system may include a memory for storing an average phase shift between the electrode contacts, representing the phase shift when there is no disturbed basilar membrane wave propagation. Alternatively, the predetermined threshold may be at least 90 degrees or at least 180 degrees.

[0013] The system may also include a transducer adapted to be placed near the patient's outer ear and operatively coupled to a control unit, the control unit being further adapted to provide a control signal to the transducer, causing the transducer to emit an acoustic signal. The acoustic signal may have a specific frequency, such as 500 Hz, 1000 Hz, or 2000 Hz. The control unit may be further adapted to determine the control signal for the transducer based at least in part on a signal representing the determined propagation of a disturbed basilar membrane wave, or alternatively may include a tone localization location associated with the propagation of the disturbed basilar membrane wave.

[0014] The system may also include an insertion detection unit adapted to provide insertion position information of the electrode array in the patient's inner ear, and a control unit further adapted to estimate the pitch localization position based on the insertion position information of the electrode array. On the other hand, the system may also include an output unit for providing a user with a signal representing the determined propagation of a disturbed basilar membrane wave, so as to indicate the propagation of the disturbed basilar membrane wave and / or the region of the disturbed basilar membrane wave propagation.

[0015] A system for monitoring the insertion of an electrode array into a patient's inner ear, according to one aspect of the invention, comprises: an output unit; an insertion detection unit adapted to provide insertion location information of the electrode array in the patient's inner ear; a measurement unit for measuring electrocochlear electrograph (ECochG) signals of electrode contacts of the electrode array located in the patient's inner ear; and a control unit adapted to perform the following steps: when an acoustic signal of a predetermined frequency is applied to the patient's outer ear, measuring, using the measurement unit, the ECochG signals of at least a subset of the electrode contacts of the electrode array located in the patient's inner ear. The control unit is further adapted to perform the following steps: selecting a first electrode contact and a second electrode contact based at least in part on the peak amplitude of the measured ECochG signals. The control unit is further adapted to perform the following steps: determining a first phase shift of the selected first electrode contact and a second phase shift of the selected second electrode contact based on the associated measured ECochG signals. The control unit is further adapted to perform the following step: determining, at least in part, that a disturbed basilar membrane wave propagation exists in the region from a selected first electrode contact to a selected second electrode contact, based on the fact that the phase difference between the first phase shift and the second phase shift exceeds a predetermined threshold. The control unit is further adapted to perform the following step: providing a signal representing the determined disturbed basilar membrane wave propagation on an output unit.

[0016] The control unit can be further adapted to estimate the tone localization location associated with the propagation of the disturbed basilar membrane wave based on the insertion position information of the electrode array, and to provide tone localization location information on the output unit.

[0017] The system may also include a transducer adapted to be placed near the patient's outer ear and operatively coupled to a control unit, the control unit being further adapted to provide a control signal to the transducer causing the transducer to emit an acoustic signal. The control unit may be further adapted to determine the control signal for the transducer based at least in part on a signal representing the determined perturbed basilar membrane wave propagation, or alternatively, to determine a tone localization location, including one associated with the perturbed basilar membrane wave propagation, based at least in part on a signal representing the determined perturbed basilar membrane wave propagation.

[0018] The system may also include a user input unit through which a user can at least partially adjust a predetermined threshold. The control unit may be adapted to apply the predetermined threshold, which includes a phase shift between the first electrode contact and the second electrode contact, when there is no disturbed basement membrane wave propagation. Attached Figure Description

[0019] This document describes embodiments of the present invention in conjunction with the accompanying drawings, in which:

[0020] Figure 1 (Prior art) shows a typical human ear with an electroacoustic hearing implant system.

[0021] Figures 2A-2B The measured ECochG signal amplitude (A) and ECochG signal phase (B) at each electrode contact are shown when the propagation of the basement membrane wave is undisturbed.

[0022] Figure 3 A flowchart illustrating a method according to an embodiment of the present invention is shown.

[0023] Figures 4A-4B The measured ECochG signal amplitude (A) and ECochG signal phase (B) at each electrode contact are shown when the propagation of the basement membrane wave is disturbed.

[0024] Figures 5A-5B The measured ECochG signal amplitude (A) and ECochG signal phase (B) at each electrode contact are shown when the propagation of the basement membrane wave is disturbed.

[0025] Figures 6A-6B The measured ECochG signal amplitude (A) and ECochG signal phase (B) at each electrode contact are shown when the propagation of the basement membrane wave is disturbed.

[0026] Figure 7 This is a schematic diagram of a system for monitoring an electrode array inserted into a patient's inner ear, according to an embodiment of the present invention. Detailed Implementation

[0027] To facilitate understanding of the principles of the invention, reference will now be made to the examples shown in the accompanying drawings, and the same examples will be described using specific language. However, it should be understood that this is not intended to limit the scope of the invention, and such changes and further modifications in the illustrated apparatus, as well as such further applications of the principles of the invention illustrated therein, are now or in the future to those skilled in the art relating to the invention.

[0028] Embodiments of the present invention provide useful information regarding the propagation of disturbed basilar membrane waves, which can be used to provide real-time intraoperative feedback to the surgeon. This helps in assessing surgical steps and guiding the surgeon to minimize the propagation of disturbed basilar membrane waves during the insertion of the cochlear implant electrode array into the patient's inner ear. Upon detection of disturbed basilar membrane wave propagation, the surgeon may slightly pull back or rotate the electrode array before continuing insertion. Depending on the area where disturbed basilar membrane wave propagation is detected, the surgeon may apply appropriate manual interventions (e.g., rotating or withdrawing the electrode array) during the insertion of the cochlear implant electrode array. The method for detecting disturbed basilar membrane wave propagation can be used at any time during electrode array insertion, when the electrode array is fully inserted, or even postoperatively for diagnostic purposes.

[0029] Figure 2A The electrocochlear electrogram (ECochG) signals measured for each electrode contact are shown. Figure 2B The phase shift of the ECochG signal at each electrode contact is shown when the basilar membrane wave propagation is undisturbed. Electrocochleography (or ECochG as used throughout this specification) refers to a clinical measurement technique that can be used, for example, to assess a recipient's residual hearing. ECochG involves delivering acoustic stimulation to the patient's cochlea (e.g., using a transducer placed near the patient's outer ear) and measuring electrical signals (typically voltages) at one or more electrode contacts of an electrode array. These responses are the ECochG signals and are shown as a function of time (x-axis) for each measured electrode contact (labeled with electrode contact number on the y-axis). Figure 2A In the diagram on the right, the acoustic signal can have a predetermined frequency and can be transmitted from the patient's outer ear to the patient's inner ear, where the ECochG response / signal is measured at, for example, the electrode contacts of an electrode array located in the patient's inner ear. The acoustic signal is preferably a sinusoidal signal or a signal with a narrow bandwidth, but any acoustic signal can be used as long as it induces wavering on at least the portion of the basilar membrane where the electrode array may contact the basilar membrane and potentially cause the propagation of disturbed basilar membrane waves. The predetermined frequency of the acoustic signal can be, for example, 500 Hz, 1000 Hz, or 2000 Hz, or it can be a function of the insertion position of the electrode array in the patient's inner ear, which can be based on the pitch localization position of the electrode array tip. Figure 2A The upper left side shows the amplitude of the ECochG signal on the y-axis for each measured electrode contact on the x-axis. The term peak amplitude for an electrode contact refers to an ECochG signal amplitude at that electrode contact that is statistically significantly higher than the ECochG signal amplitudes of two directly adjacent measured electrode contacts. Figure 2A The lower left side shows the latency of the basilar membrane traveling wave. Figure 2BThe phase shift on the y-axis for each measured electrode contact (on the x-axis) relative to a (time) reference is shown. The reference can be an acoustic signal or an ECochG signal measured for a selected electrode contact. Figure 2B In the diagram, electrode contact number 12 is a reference, therefore the phase shift of this electrode is zero.

[0030] Figure 3 A flowchart illustrating an exemplary embodiment of the invention for detecting the propagation of a disturbed basilar membrane wave is shown. In step 301, when an acoustic signal of a predetermined frequency is applied to the patient's outer ear, an electrocochlear electrogram (ECochG) signal of a subset of electrode contacts of an electrode array located in the patient's inner ear is measured. The electrode array includes a plurality of electrode contacts along its length on its outer surface, which provide selective electrical stimulation or allow selective measurement of the ECochG signal within the cochlea. The electrode contacts are numbered in ascending order from the tip to the rear end of the electrode assembly adjacent to the electrode lead, and vice versa. For example, electrode contact E5 is adjacent to electrode contacts E4 and E3. The acoustic signal may have a predetermined frequency and may be transmitted through the patient's outer ear to the patient's inner ear using a transducer. Without departing from the spirit of the invention, it should be understood that the acoustic signal may be transmitted to the inner ear from transducers located in various other locations, such as near or fixed to a bone in the ossicles or near the oval or round window. Other methods of transmitting acoustic signals to the inner ear include bone conduction. In this example, the transducer is placed on the patient's head.

[0031] The acoustic signal is preferably a sinusoidal signal or a signal with a narrow bandwidth, but any acoustic signal can be used as long as it induces wavering on at least the portion of the basilar membrane where the electrode array may contact the basilar membrane and potentially cause perturbed basilar wave propagation. The amplitude of the acoustic signal can be 40 dB higher than the hearing threshold. The predetermined frequency of the acoustic signal can be, for example, 500 Hz, 1000 Hz, or 2000 Hz, or it can be a function of the insertion position of the electrode array in the patient's inner ear, which can be based on the pitch localization position of the electrode array tip. The predetermined frequency of the acoustic signal can also be selected to be lower than or equal to the pitch localization position of the estimated area where the basilar wave propagation may be perturbed. This can be achieved by first determining the area where the basilar wave propagation may be perturbed according to the method of the invention described herein, and once the area is detected, using the frequency corresponding to the pitch localization position of the estimated area where the basilar wave propagation is perturbed as the acoustic signal. Using such an acoustic signal improves the sensitivity of the measurement, and even very small perturbations can subsequently be detected.

[0032] In step 302, the first and second electrode contacts are selected at least in part based on the peak amplitude of the measured electrocochlear imaging (ECochG) signal. The term peak amplitude for an electrode contact refers to an ECochG signal amplitude at that electrode contact that is statistically significantly higher than the ECochG signal amplitudes of two directly adjacent electrode contacts being measured. (Reference) Figure 4A Examples of peak amplitude are shown for electrode contacts numbered E2, E5, E7, and E10, see reference. Figure 6A Examples of peak amplitudes are electrode contacts numbered E2, E5, and E10. In step 303, a first phase shift of the selected first electrode contact and a second phase shift of the selected second electrode contact are determined based on the associated measured electrocochlear imaging (ECochG) signal. Examples of the determined phase shifts for each measured electrode contact are shown in... Figure 4B , 5B And 6B. Phase shift is in radians; negative values ​​indicate the difference in ECochG signal at each electrode contact compared to the reference. Figure 2A Shift left in the chart on the right. In the time domain of the ECochG signal, this corresponds to the signal leading the reference in time.

[0033] In step 304, it is determined, at least in part, whether there is disturbed basilar membrane wave propagation in the region from the selected first electrode contact to the selected second electrode contact based on the condition that the difference between the first and second phase shifts exceeds a predetermined threshold. The predetermined threshold may include the phase shift between the first and second electrode contacts when there is no disturbed basilar membrane wave propagation. This has the advantage that the threshold takes into account the phase shift that naturally occurs when there is no disturbed basilar membrane wave propagation, thus allowing for a better setting of the threshold and improved detection. In another example, the predetermined threshold may be at least 90 degrees or at least 180 degrees, and may include or exclude the phase shift between the first and second electrode contacts when there is no disturbed basilar membrane wave propagation.

[0034] If a region with disturbed basilar membrane wave propagation is detected in step 304, a signal representing the determined disturbed basilar membrane wave propagation is provided in step 305, for example, but not limited to, to an output unit 705 which may include a display and / or a buzzer. For example, during electrode array insertion, the surgeon can hear an alarm signal via the buzzer and keep their attention on the electrode array insertion area. In the presence of other ECochG peak amplitudes, in step 306, another region of disturbed basilar membrane wave propagation can be detected according to the method of the invention. It should be noted that this step is optional. In a similar and optional manner, the steps beginning with step 301 can be repeated, thereby enabling, for example, real-time detection during the insertion of the electrode array into the patient's inner ear.

[0035] Figures 4A-4B , Figures 5A-5B and Figures 6A-6B An example of in vivo measurements is shown. All measurements were acquired with the electrode array fully inserted and using an acoustic signal frequency of 500 Hz. ECochG was measured on all electrodes except for electrode contact number 4, which was deactivated. Figure 4A The graph on the right shows the ECochG signal of all measured electrode contacts as a function of time. The graph on the left shows the ECochG amplitude of each measured electrode contact. This description is consistent with... Figure 2A The same is used, and it is used in the same way. Figure 5A and Figure 6A . Figure 4B The phase shift of the ECochG signal for each measured electrode contact is shown. This description is consistent with... Figure 2B The same is used, and it is used in the same way. Figure 5B and Figure 6B .from Figure 4A The peak amplitude can be seen in the chart on the left. These are electrode contacts numbered E2, E5, E7, and E10. From... Figure 4B The phase shift of each measured electrode contact can be observed. Phase shifts exceeding a predetermined threshold occur at electrode contact numbers E2, E6, and E10. Figure 5A and Figure 5B In the measurements, taken from the same patient and after the surgeon withdrew the electrode array by 0.5 mm, electrode contacts numbered E2, E5, E7, and 10 still exhibited peak amplitudes, but the phase shift at electrode contact E10 disappeared. Finally, Figure 6A and Figure 6B In this example, after withdrawing the electrode array by 0.5 mm, it was fully reinserted, and the ECochG was measured again. In this case, electrode contacts numbered E2, E5, and E10 exhibited peak amplitudes, but the peak amplitude at electrode contact E7 disappeared. Reinsertion did not change the phase shift; therefore, after withdrawing the electrode array by 0.5 mm and reinserting it, a phase shift exceeding a predetermined threshold was only observed for electrode contacts E2 and E5.

[0036] Figure 7 An exemplary system for detecting the propagation of disturbed basilar membrane waves is schematically illustrated, or an electrode array inserted into the patient's inner ear suitable for detecting the propagation of disturbed basilar membrane waves according to the present invention is shown below. Reference will be made to... Figure 7 A system for detecting the propagation of a disturbed basilar membrane wave is described by way of example.

[0037] A system for detecting the propagation of a disturbed basilar membrane wave includes a measurement unit 704 and a control unit 701 for measuring electrocochlear electrogram (ECochG) signals of electrode contacts of an electrode array located in the patient's inner ear. The control unit 701 is adapted to perform the following steps: first, when an acoustic signal of a predetermined frequency is applied to the patient's outer ear, the measurement unit 701 measures the ECochG signals for at least a portion of the electrode contacts of the electrode array located in the patient's inner ear. The control unit 701 is further adapted to subsequently select a first electrode contact and a second electrode contact based at least in part on the peak amplitude of the measured ECochG signals. The control unit 701 is further adapted to subsequently determine a first phase shift of the selected first electrode contact and a second phase shift of the selected second electrode contact based on the associated measured ECochG signals. In the next step, the control unit 701 is adapted to determine, at least in part, that a disturbed basilar membrane wave propagation exists in the region from the selected first electrode contact to the selected second electrode contact, based on the fact that the phase difference between the first phase shift and the second phase shift exceeds a predetermined threshold. Finally, the control unit 701 is adapted to provide a signal representing the determined disturbed basilar membrane wave propagation.

[0038] The control unit 701 is further adapted to apply a predetermined threshold, which includes a phase shift between the first and second electrode contacts when there is no disturbed basilar membrane wave propagation. For this purpose, the control unit 701 may include a memory for storing an average phase shift between the electrode contacts, representing the phase shift when there is no disturbed basilar membrane wave propagation. The average phase shift may be the average of measurements obtained from a large number of patients with the electrode array fully inserted or not inserted at all and with no disturbed basilar membrane wave propagation. The average phase shift may be stored as a parametric function, such as a polynomial or logarithmic fitting function. The parametric function may be patient-adapted. For example, actual ECochG measurements from patients can be used to fine-tune the parameters of the function to adapt it to individual patients. This can improve detection. Alternatively or supplementally, the predetermined threshold may be at least 90 degrees or at least 180 degrees.

[0039] Optionally, the system for detecting the propagation of disturbed basilar membrane waves also includes an acoustic transducer adapted to be placed near the patient's outer ear and operatively coupled to control unit 701. Control unit 701 is further adapted to provide a control signal to the transducer, causing the transducer to emit an acoustic signal. The acoustic signal may have a predetermined frequency and may be transmitted from the transducer through the patient's outer ear to the patient's inner ear. Without departing from the inventive concept, it should be understood that the acoustic signal can be transmitted to the inner ear via transducers located in various other locations, such as near or fixed to a bone in the ossicles or near the oval or round window. Other methods of transmitting acoustic signals to the inner ear include bone conduction. In this example, the transducer is placed on the patient's head.

[0040] Control unit 701 can output a control signal such that the acoustic signal generated by the transducer is a sinusoidal signal or a signal with a narrow bandwidth. However, it should be understood that any acoustic signal can be used, as long as it induces wavering on at least the portion of the basilar membrane where the electrode array may contact the basilar membrane and may cause perturbed basilar membrane wave propagation. Control unit 701 can output a control signal such that the amplitude of the acoustic signal generated by the transducer is 40 dB higher than the hearing threshold. Control unit 701 can output a control signal such that the transducer generates an acoustic signal of a predetermined frequency, such as 500 Hz, 1000 Hz, or 2000 Hz, or the predetermined frequency may be a function of the insertion position of the electrode array in the patient's inner ear, which may be based on the tone localization position of the electrode array tip. Alternatively or additionally, control unit 701 can select the predetermined frequency of the acoustic signal to be lower than or equal to the tone localization position of the estimated area where basilar membrane wave propagation may be perturbed. This can be achieved by first referring to the above reference... Figure 3 The method of the present invention describes the determination of regions where basilar membrane wave propagation may be disturbed. Once this region is detected, an acoustic signal is used, corresponding to the frequency of the estimated pitch localization location of the disturbed region. Using such an acoustic signal frequency improves the sensitivity of the measurement and allows even very small disturbances to be detected.

[0041] Optionally, the system for detecting disturbed basilar membrane wave propagation further includes an output unit 705 for providing a signal to the user representing the determined disturbed basilar membrane wave propagation, so as to indicate the disturbed basilar membrane wave propagation and / or the area of ​​the disturbed basilar membrane wave propagation. It should be noted that other means of outputting information to the user are also applicable to the inventive concept. For example, when disturbed basilar membrane wave propagation is detected, a buzzer can provide an acoustic alarm signal to the surgeon.

[0042] While the foregoing primarily applies to systems for monitoring electrode array insertion according to one aspect of the invention, the following description is provided by way of example and reference only. Figure 7This describes a system used to monitor the insertion of an electrode array.

[0043] A system for monitoring the insertion of an electrode array into a patient's inner ear includes: an output unit 705, an insertion detection unit 702 adapted to provide insertion location information of the electrode array in the patient's inner ear, a measurement unit 704 for measuring electrocochlear electrogram (ECochG) signals of the electrode contacts of the electrode array located in the patient's inner ear, and a control unit 701. The control unit 701 is adapted to perform the following steps: when an acoustic signal of a predetermined frequency is applied to the patient's outer ear, the measurement unit 701 measures the ECochG signals for at least a portion of the electrode contacts of the electrode array located in the patient's inner ear. The control unit 701 is further adapted to perform the following steps: selecting a first electrode contact and a second electrode contact based at least in part on the peak amplitude of the measured ECochG signals. The control unit 701 is adapted to subsequently determine a first phase shift of the selected first electrode contact and a second phase shift of the selected second electrode contact based on the associated measured ECochG signals. Control unit 701 is adapted to perform the following operation in the next step: determining, at least in part, that a disturbed basilar membrane wave propagation exists in the region from the selected first electrode contact to the selected second electrode contact, based on the fact that the phase difference between the first phase shift and the second phase shift exceeds a predetermined threshold. Finally, control unit 701 is adapted to provide a signal representing the determined disturbed basilar membrane wave propagation on output unit 705. Output unit 705 may include a display and / or a buzzer and / or a network interface.

[0044] The control unit 701 can be further adapted to estimate the pitch localization location associated with the propagation of the disturbed basilar membrane wave based on the electrode array insertion position information, and provide the pitch localization location information on the output unit 705.

[0045] The system for monitoring the insertion of an electrode array into a patient's inner ear also includes an acoustic transducer adapted to be placed near the patient's outer ear and operatively coupled to a control unit 701. The control unit 701 is further adapted to provide a control signal to the transducer, causing the transducer to emit an acoustic signal. The acoustic signal may have a predetermined frequency and may be transmitted from the transducer through the patient's outer ear to the patient's inner ear. Without departing from the inventive concept, it should be understood that the acoustic signal can be transmitted to the inner ear via transducers located in various other locations, such as near or fixed to a bone in the ossicles or near the oval or round window. Other methods of transmitting acoustic signals to the inner ear include bone conduction. In this example, the transducer is placed on the patient's head.

[0046] Control unit 701 can output a control signal such that the acoustic signal generated by the transducer is a sinusoidal signal or a signal with a narrow bandwidth. However, it should be understood that any acoustic signal can be used, as long as it induces wavering on at least the portion of the basilar membrane where the electrode array may contact the basilar membrane and may cause perturbed basilar membrane wave propagation. Control unit 701 can output a control signal such that the amplitude of the acoustic signal generated by the transducer is 40 dB higher than the hearing threshold. Control unit 701 can output a control signal such that the transducer generates an acoustic signal of a predetermined frequency, such as 500 Hz, 1000 Hz, or 2000 Hz, or the predetermined frequency may be a function of the insertion position of the electrode array in the patient's inner ear, which may be based on the tone localization position of the electrode array tip. Alternatively or additionally, control unit 701 can select the predetermined frequency of the acoustic signal to be lower than or equal to the tone localization position of the estimated area where basilar membrane wave propagation may be perturbed. This can be achieved by first referring to the above reference... Figure 3 The method of the present invention describes the determination of regions where basilar membrane wave propagation may be disturbed. Once this region is detected, an acoustic signal is used, corresponding to the frequency of the estimated pitch localization location of the disturbed region. Using such an acoustic signal frequency improves the sensitivity of the measurement and allows even very small disturbances to be detected.

[0047] The system may include an input unit (not shown) through which a user can at least partially adapt a predetermined threshold. The control unit 701 is further adapted to apply the predetermined threshold, which includes a phase shift between the first and second electrode contacts when there is no disturbed basilar membrane wave propagation. For this purpose, the control unit 701 may include a memory for storing an average phase shift between the electrode contacts to represent the phase shift when there is no disturbed basilar membrane wave propagation. The average phase shift may be the average of measurements obtained from a large number of patients with the electrode array fully inserted or not inserted at all and with no disturbed basilar membrane wave propagation. The average phase shift may be stored as a parametric function, such as a polynomial or logarithmic fitting function. The parametric function may be patient-adapted. For example, actual ECochG measurements from patients can be used to fine-tune the parameters of the function to adapt it to an individual patient. This can improve detection. Alternatively or supplementally, the predetermined threshold may be at least 90 degrees or at least 180 degrees.

Claims

1. A method for detecting the propagation of a disturbed basilar membrane wave, characterized in that, Includes the following steps: When an acoustic signal of a predetermined frequency is applied to the patient’s outer ear, an electrocochleography (ECochG) signal is measured at at least a subset of the electrode contacts of an electrode array located in the patient’s inner ear. as well as The first electrode contact and the second electrode contact are selected based at least in part on the peak amplitude of the measured electrocochlear imaging (ECochG) signal; and Based on the associated measured electrocochleography (ECochG) signal, determine the first phase shift of the selected first electrode contact and the second phase shift of the selected second electrode contact; as well as The presence of a disturbed basement membrane wave propagation in the region from the selected first electrode contact to the selected second electrode contact is determined at least in part based on the fact that the difference between the first phase shift and the second phase shift exceeds a predetermined threshold.

2. The method for detecting disturbed basement membrane wave propagation according to claim 1, characterized in that, When there is no disturbed basement membrane wave propagation, the predetermined threshold includes the phase shift between the first electrode contact and the second electrode contact.

3. The method for detecting disturbed basement membrane wave propagation according to claim 1 or 2, characterized in that, The predetermined threshold is at least 90 degrees or at least 180 degrees.

4. The method for detecting the propagation of a disturbed basilar membrane wave according to any one of claims 1 to 3, characterized in that, The predetermined frequency of the acoustic signal is 500Hz, 1000Hz or 2000Hz.

5. The method for detecting the propagation of a disturbed basilar membrane wave according to any one of claims 1 to 3, characterized in that, The predetermined frequency of the acoustic signal is a function of the insertion position of the electrode array in the patient's inner ear.

6. The method for detecting disturbed basement membrane wave propagation according to claim 6, characterized in that, The function determines the predetermined frequency based on the tone positioning position of the tip of the electrode array.

7. The method for detecting the propagation of a disturbed basilar membrane wave according to any one of claims 1 to 3, characterized in that, The predetermined frequency of the acoustic signal is selected to be below or within the estimated region of the pitch location, the estimated region being determined based on the method of any one of claims 1 to 3, in which wave propagation of the basement membrane is disturbed.

8. The method for detecting disturbed basilar membrane wave propagation according to any one of the preceding claims, characterized in that, The amplitude of the acoustic signal is at least 40 dB higher than the hearing threshold.

9. The method for detecting disturbed basilar membrane wave propagation according to any one of the preceding claims, characterized in that, The selection of the first and second electrode contacts is based, at least in part, on the adjacent peak amplitudes of the measured electrocochlear imaging (ECochG) signals.

10. A system for detecting the propagation of a disturbed basilar membrane wave, characterized in that, The system includes a measurement unit for measuring electrocochlear electrograph (ECochG) signals at electrode contacts of an electrode array located in the patient's inner ear, and a control unit adapted to perform the following steps: When an acoustic signal of a predetermined frequency is applied to the patient’s outer ear, the electrocochleography (ECochG) signal is measured using the measurement unit at at least a subset of the electrode contacts of the electrode array located in the patient’s inner ear. The first electrode contact and the second electrode contact are selected based at least in part on the peak amplitude of the measured electrocochlear imaging (ECochG) signal; and Based on the associated measured electrocochleography (ECochG) signal, determine the first phase shift of the selected first electrode contact and the second phase shift of the selected second electrode contact; as well as At least in part, it is determined that a disturbed basement membrane wave propagates in the region from the selected first electrode contact to the selected second electrode contact when the phase difference between the first phase shift and the second phase shift exceeds a predetermined threshold; and It provides a signal representing the propagation of the identified disturbed basilar membrane wave.

11. The system for detecting disturbed basement membrane wave propagation according to claim 10, characterized in that, The control unit is adapted to apply a predetermined threshold, which includes the phase shift between the first electrode contact and the second electrode contact when there is no disturbed basement membrane wave propagation.

12. The system for detecting disturbed basement membrane wave propagation according to claim 11, characterized in that, The system includes a memory for storing the average phase shift between electrode contacts, the average phase shift representing the phase shift when there is no disturbed basement membrane wave propagation.

13. The system for detecting the propagation of a disturbed basilar membrane wave according to any one of claims 10 to 12, characterized in that, The predetermined threshold is at least 90 degrees or at least 180 degrees.

14. The system for detecting disturbed basement membrane wave propagation according to any one of claims 10 to 12, characterized in that, The device further includes a transducer adapted to be placed near the patient's outer ear and operatively coupled to the control unit, the control unit being further adapted to provide a control signal to the transducer, causing the transducer to emit an acoustic signal.

15. The system for detecting disturbed basement membrane wave propagation according to claim 14, characterized in that, The control signal is adapted to give the emitted acoustic signal a specific frequency.

16. The system for detecting disturbed basement membrane wave propagation according to claim 15, characterized in that, The frequency is any one of 500Hz, 1000Hz or 2000Hz.

17. The system for detecting disturbed basement membrane wave propagation according to claim 14, characterized in that, The control unit is further adapted to determine control signals for the transducer based at least in part on signals representing the determined propagation of the disturbed basilar membrane wave.

18. The system for detecting disturbed basement membrane wave propagation according to claim 17, characterized in that, The control signal is determined, at least in part, based on a signal representing the identified perturbed basilar membrane wave propagation, including a pitch positioning location associated with the perturbed basilar membrane wave propagation.

19. The system for detecting disturbed basement membrane wave propagation according to claim 18, characterized in that, The system further includes an insertion detection unit adapted to provide insertion position information of the electrode array in the patient's inner ear, and the control unit is further adapted to estimate the tone localization position based on the insertion position information of the electrode array.

20. The system for detecting disturbed basement membrane wave propagation according to any one of claims 10 to 19, characterized in that, The system further includes an output unit for providing a user with a signal representing the determined propagation of a disturbed basilar membrane wave, so as to indicate the propagation of the disturbed basilar membrane wave and / or the region of the propagation of the disturbed basilar membrane wave.

21. A system for monitoring an electrode array inserted into a patient's inner ear, characterized in that, The system includes an output unit, an insertion detection unit adapted to provide insertion position information of the electrode array in the patient's inner ear, a measurement unit for measuring electrocochlear electrogram (ECochG) signals of the electrode contacts of the electrode array located in the patient's inner ear, and a control unit adapted to perform the following steps: When an acoustic signal of a predetermined frequency is applied to the patient’s outer ear, the electrocochleography (ECochG) signal is measured using the measurement unit at at least a subset of the electrode contacts of the electrode array located in the patient’s inner ear. The first electrode contact and the second electrode contact are selected based at least in part on the peak amplitude of the measured electrocochlear imaging (ECochG) signal; and Based on the associated measured electrocochleography (ECochG) signal, determine the first phase shift of the selected first electrode contact and the second phase shift of the selected second electrode contact; as well as At least in part, it is determined that a disturbed basement membrane wave propagates in the region from the selected first electrode contact to the selected second electrode contact when the phase difference between the first phase shift and the second phase shift exceeds a predetermined threshold; and A signal representing the determined perturbed membrane wave propagation is provided on the output unit.

22. The system for monitoring an electrode array inserted into a patient's inner ear according to claim 21, characterized in that, The control unit is further adapted to estimate the pitch localization location associated with the propagation of the disturbed basilar membrane wave based on the insertion position information of the electrode array, and to provide the pitch localization location information on the output unit.

23. The system for monitoring an electrode array inserted into a patient's inner ear according to claim 21 or 22, characterized in that, The device further includes a transducer adapted to be placed near the patient's outer ear and operatively coupled to the control unit, wherein the control unit is further adapted to provide a control signal to the transducer, causing the transducer to emit an acoustic signal.

24. The system for monitoring an electrode array inserted into a patient's inner ear according to any one of claims 21 to 23, characterized in that, The control unit is further adapted to determine control signals for the transducer based at least in part on signals representing the determined propagation of the disturbed basilar membrane wave.

25. The system for detecting disturbed basement membrane wave propagation according to claim 24, characterized in that, The control signal is determined, at least in part, based on a signal representing the identified perturbed basilar membrane wave propagation, including a pitch positioning location associated with the perturbed basilar membrane wave propagation.

26. The system for detecting disturbed basilar membrane wave propagation according to claim 24, characterized in that, The system further includes a user input unit through which a user can at least partially adapt the predetermined threshold.

27. The system for detecting disturbed basement membrane wave propagation according to any one of claims 21 to 26, characterized in that, When there is no disturbed basement membrane wave propagation, the predetermined threshold includes the phase shift between the first electrode contact and the second electrode contact.

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