Apparatus and method for evaluating device function of bilateral sensory system

Abstract

An apparatus includes at least one first microphone configured to be worn on or within a body of a recipient and configured to generate a microphone signal indicative of ambient sound from an environment of the recipient. The device also includes first circuitry configured to generate a stimulation signal in response to the microphone signal, the stimulation signal indicative of the ambient sound and configured to be received by a body of the recipient to evoke a hearing perception of the recipient. The apparatus also includes second circuitry configured to generate first data indicative of a first comparison of responses of the at least one first microphone and at least one second microphone to the ambient sound at a first time. The second circuitry is further configured to generate second data indicative of a second comparison of responses of the at least one first microphone and the at least one second microphone to the ambient sound at a second time. The second time is after the first time. The second circuitry is further configured to generate a performance evaluation of at least one aspect of the device in response to a third comparison of the first data to the second data.

Description

Background Technical Field

[0002] The present application generally relates to medical implants and / or other systems having active components (e.g., transducers; actuators; microphones; sensors) that respond to sensory stimuli from the surrounding environment. Background Art

[0003] In recent decades, medical devices have provided a wide range of therapeutic benefits to recipients. Medical devices can 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 for many 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 within a recipient. These functional devices are generally used for diagnosing, preventing, monitoring, treating, or managing diseases / injuries or their symptoms, or for studying, replacing, or modifying 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 disclosed herein, a device includes at least one first microphone configured to be worn on or within a recipient's body. The at least one first microphone is configured to generate a microphone signal indicative of ambient sound from the recipient's environment. The device further includes a first circuitry configured to receive the microphone signal and, in response to the microphone signal, generate a stimulation signal configured to be received by the recipient's body to evoke a hearing perception of the recipient. The stimulation signal is indicative of the ambient sound. The device further includes a second circuitry configured to generate first data indicative of a first comparison of a response of the at least one first microphone to the ambient sound at a first time with a response of at least one second microphone to the ambient sound at the first time. The second circuitry is further configured to generate second data indicative of a second comparison of a response of the at least one first microphone to the ambient sound at a second time with a response of the at least one second microphone of the device to the ambient sound at the second time. The second time is after the first time. The second circuitry is further configured to generate a performance evaluation of at least one aspect of the device in response to a third comparison of the first data with the second data.

[0006] In another aspect disclosed herein, a device includes a communication circuitry configured to receive first information from at least one first transducer and second information from at least one second transducer. The first information and the second information indicate signals from a recipient's environment or from the recipient's body. The device further includes an evaluation circuitry configured to, during a first time period: receive a first portion of the first information, the first portion of the first information indicating a response of the at least one first transducer to the signal during the first time period; receive a first portion of the second information, the first portion of the second information indicating a response of the at least one second transducer to the signal during the first time period; and generate a first comparison of the first portion of the first information and the first portion of the second information. The evaluation circuitry is further configured to, during a second time period after the first time period: receive a second portion of the first information, the second portion of the first information indicating a response of the at least one first transducer to the signal during the second time period; receive a second portion of the second information, the second portion of the second information indicating a response of the at least one second transducer to the signal during the second time period; and generate a second comparison of the second portion of the first information and the second portion of the second information. The evaluation circuitry is further configured to generate a third comparison of the first comparison and the second comparison.

[0007] In another aspect disclosed herein, a method includes measuring and storing a first difference value between responses of a first prosthesis and a second prosthesis to an environmental stimulus at a first time. The method further includes measuring and storing at least one second difference value between responses of the first prosthesis and the second prosthesis to the environmental stimulus at a second time after the first time. The method further includes detecting performance degradation of one of the first prosthesis and the second prosthesis, the detecting including comparing the at least one first difference value with the second difference value.

[0008] In another aspect disclosed herein, a device includes: a first device including at least one first transducer configured to respond to a signal; and a second device including at least one second transducer configured to respond to the signal. At least one of the first device and the second device is configured to be worn on or implanted in a recipient's body. The device further includes a first circuitry configured to generate first data indicative of a first comparison of a response of the at least one first transducer to the signal at a first time with a response of the at least one second transducer to the signal at the first time. The device further includes a second circuitry configured to generate second data indicative of a second comparison of a response of the at least one first transducer to the signal at a second time with a response of the at least one second transducer to the signal at the second time. The second time is after the first time. The device further includes a third circuitry configured to generate a performance assessment of at least one aspect of the device in response to a third comparison of the first data with the second data. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0010] FIG. 1A is a perspective view of an exemplary cochlear implant auditory prosthesis implanted in a recipient according to certain embodiments described herein;

[0011] FIG. 1B is a perspective view of an exemplary fully implantable middle ear implant auditory prosthesis implanted in a recipient according to certain embodiments described herein;

[0012] FIG. 1C schematically shows a portion of another exemplary transcutaneous bone conduction sensory prosthesis implanted in a recipient according to certain embodiments described herein;

[0013] FIG. 1D schematically shows a portion of an exemplary acoustic hearing prosthesis including a portion at least partially positioned within a recipient's ear canal according to certain embodiments described herein;

[0014] FIGS. 2A and 2B schematically show an exemplary device according to certain embodiments described herein;

[0015] FIG. 2C schematically shows an exemplary information flow diagram according to two exemplary devices according to certain embodiments described herein;

[0016] FIGS. 3A and 3B are for use in a performance assessment of a sensory prosthesis system (e.g., a bilateral acoustic prosthesis system) at time t, respectively, according to certain embodiments described hereinn performing an initial test at and at time t m flowchart of an example method of performing a subsequent test at; and

[0017] FIG. 4 is a flowchart of an example method for detecting performance degradation in one of a first sensory prosthesis and a second sensory prosthesis of a sensory prosthesis system (e.g., a bilateral acoustic prosthesis system) according to certain embodiments described herein. DETAILED DESCRIPTION

[0018] Certain embodiments described herein provide a self - contained performance testing function for sensory prostheses worn by a recipient in both ears. This performance testing function can continuously monitor a bilateral acoustic prosthesis system over a relatively long period of time (e.g., days; weeks; months) by comparing the signal processing characteristics of the acoustic prostheses with each other. The signal processing characteristics are monitored passively by comparing the difference in the responses of the two acoustic prostheses to ambient sounds at a first time period with the difference in the responses of the two acoustic prostheses to ambient sounds at a second time period after the first time period. By utilizing the relative difference (e.g., as opposed to the absolute difference) between the responses of the two acoustic prostheses to the same ambient sound, certain embodiments provide the ability to identify changes and / or trends (e.g., rather than just pass / fail) in the performance of the microphone and / or the sound processing circuitry over time, and can detect faults other than a problem with the microphone (e.g., a blocked microphone cover port). Certain embodiments provide the ability to run tests without additional hardware other than the two acoustic prostheses and to run tests when neither of the two acoustic prostheses has a reliable acoustic output. By relying on data from at least two acoustic prostheses, certain embodiments can reduce the likelihood of errors in signal processing hardware or firmware causing false fails or false passes. Compared to a similar comparison between two microphones on a single device, certain embodiments provide a more robust performance (e.g., reducing the likelihood of a false pass due to equally degraded performance of the two microphones).

[0019] The teachings detailed herein are applicable in at least some embodiments to any type of medical system (e.g., implantable or wearable). For example, a medical system can sense or receive information from the surrounding environment or from the recipient's body. Medical systems of certain embodiments utilize a transducer assembly configured to provide a stimulation signal (e.g., an electrical stimulation signal; an optical stimulation signal; an electromagnetic stimulation signal; a vibratory stimulation signal; an acoustic stimulation signal) to the recipient's body in response to received information and / or control signals (e.g., an implantable sensor prosthesis; an implantable stimulation system). For example, a medical system can include an auditory prosthesis system and / or an auditory hearing device configured to generate and apply a stimulation signal (e.g., electrical and / or vibratory) that is perceived by the recipient as sound (e.g., evoking a hearing perception). Such wearable transducer assemblies can include a hearing aid device and / or a consumer electronic device (e.g., headphones) configured to be placed at least partially within the recipient's ear canal or other systems having a bilateral configuration. Such implantable transducer assemblies can include, but are not limited to: electroacoustic electrical / acoustic systems, cochlear implant devices, implantable hearing aid devices, middle ear implant devices, bone conduction devices (e.g., active bone conduction devices, passive bone conduction devices, percutaneous bone conduction devices, transcutaneous bone conduction devices), direct acoustic cochlear implants (DACIs), middle ear transducers (METs), electroacoustic implant devices, other types of auditory prosthesis devices (e.g., auditory brain stimulators) and / or combinations or variations thereof, or any other suitable hearing device and / or prosthesis system with or without one or more external components. For ease of description only, the devices and methods disclosed herein are described primarily with reference to illustrative bilateral systems (e.g., an auditory system including two auditory devices on substantially opposite sides of a recipient's skull simultaneously), but embodiments can include any type of bilateral sensory prosthesis that can utilize the teachings detailed herein and / or variations thereof. Certain embodiments described herein can be referred to as “partially implantable,” “semi-implantable,” “mostly implantable,” “fully implantable,” or “totally implantable” auditory prostheses.

[0020] The teachings detailed herein and / or variations thereof can also be used with a variety of other medical devices that provide a wide range of therapeutic benefits to recipients, patients, or other users. For example, other sensory prosthesis systems configured to evoke other types of neural or sensory (e.g., visual, tactile, olfactory, gustatory) perception and compatible with certain embodiments described herein include, but are not limited to: vestibular devices (e.g., vestibular implants), visual devices (e.g., bionic eyes), visual prosthetics (e.g., retinal implants), somatosensory implants, and chemosensory implants. In some embodiments, the teachings detailed herein and / or variations thereof can be used in other types of implantable medical devices in addition to sensory prosthetics. For example, the devices and methods disclosed herein and / or variations thereof can also be used with one or more of the following: sensors; cardiac pacemakers; drug delivery systems; defibrillators; functional electrical stimulation devices; catheters; brain implants; seizure devices (e.g., devices for monitoring and / or treating seizure events); sleep apnea devices; electroporation; pain relief devices; and the like. Embodiments can include any type of medical system that can utilize the teachings detailed herein and / or variations thereof (e.g., a system that can benefit from having two devices in or on a recipient's body, each device having one or more transducers that measure the same aspect of the surrounding environment or the recipient's body).

[0021] FIG. 1A is a perspective view of an exemplary cochlear implant auditory prosthesis 100 implanted in a recipient according to certain embodiments described herein. The exemplary auditory prosthesis 100 is shown in FIG. 1A as including an implantable stimulator unit 120 and a microphone assembly 124 external to the recipient (e.g., a partially implantable cochlear implant). An exemplary auditory prosthesis 100 according to certain embodiments described herein (e.g., a fully implantable cochlear implant; a mostly implantable cochlear implant) can use a subcutaneously implantable microphone assembly as more fully described herein in place of the external microphone assembly 124 shown in FIG. 1A. In certain embodiments, the exemplary cochlear implant auditory prosthesis 100 of FIG. 1A can be combined with a liquid pharmaceutical reservoir as described herein.

[0022] As shown in FIG. 1A, the recipient has an outer ear 101, a middle ear 105, and an inner ear 107. In a fully functional ear, the outer ear 101 includes the auricle 110 and the ear canal 102. Sound pressure or sound waves 103 are collected by the auricle 110 and are directed into and through the ear canal 102. A tympanic membrane 104 that vibrates in response to the sound waves 103 is disposed across the distal end of the ear canal 102. This vibration is coupled through three bones of the middle ear 105 to the oval window or fenestra ovalis 112, the three bones being collectively referred to as the ossicles 106 and including the malleus 108, incus 109, and stapes 111 located in the middle ear cavity 113. The bones 108, 109, and 111 of the middle ear 105 are used to filter and amplify the sound waves 103 such that the oval window 112 articulates or vibrates in response to the vibration of the tympanic membrane 104. This vibration creates a fluid motion wave of perilymph within the cochlea 140. This fluid motion in turn activates tiny hair cells (not shown) within the cochlea 140. Activation of the hair cells causes appropriate nerve impulses to be generated and transmitted through spiral ganglion cells (not shown) and the auditory nerve 114 to the brain (also not shown), where they are perceived as sound.

[0023] The human skull is formed of many different bones that support various anatomical features. Shown in FIG. 1A is the temporal bone 115 (covered in part by the recipient's skin / muscle / fat, collectively referred to herein as tissue 119) located on the side and bottom of the recipient's skull. For ease of reference, the temporal bone 115 is referred to herein as having an upper portion 115a and a mastoid portion 115b. The upper portion 115a includes the section of the temporal bone 115 that extends above the auricle 110. That is, the upper portion 115a is the section of the temporal bone 115 that forms the lateral surface of the skull. The mastoid portion 115b, herein simply referred to as the mastoid 115b, is located below the upper portion 115a. The mastoid 115b is the section of the temporal bone 115 that surrounds the middle ear 105.

[0024] As shown in FIG. 1A, an example auditory prosthesis 100 includes one or more components that are temporarily or permanently implanted in a recipient. The example auditory prosthesis 100 is shown in FIG. 1A as having: an external component 142 that is directly or indirectly attached to the recipient's body; and an internal component 144 that is temporarily or permanently implanted within the recipient (e.g., positioned in a recess of the temporal bone adjacent to the recipient's auricle 110). The external component 142 generally includes one or more sound input elements for detecting sound (e.g., an external microphone 124), a sound processing unit 126 (e.g., disposed in a behind-the-ear unit), a power source (not shown), and an external transmitter unit 128. In the illustrative embodiment of FIG. 1A, the external transmitter unit 128 includes an external coil 130 (e.g., a wire antenna coil including multiple turns of electrically insulated single-strand or multi-strand platinum or gold wire), and preferably includes a magnet (not shown) that is directly or indirectly fixed to the external coil 130. The external coil 130 of the external transmitter unit 128 is part of an inductive radio frequency (RF) communication link with the internal component 144. The sound processing unit 126 processes the output of the microphone 124, which in the depicted embodiment is positioned outside the recipient's body by the recipient's auricle 110. The sound processing unit 126 processes the output of the microphone 124 and generates an encoded signal, sometimes referred to herein as an encoded data signal, which is provided to the external transmitter unit 128 (e.g., via a cable). It will be appreciated that the sound processing unit 126 may utilize digital processing techniques to provide frequency shaping, amplification, compression, and other signal conditioning, including conditioning based on recipient-specific fitting parameters.

[0025] The power source of the external component 142 is configured to provide power to the auditory prosthesis 100, where the auditory prosthesis 100 includes a battery (e.g., located within the internal component 144 or disposed at a separate implant location) that is charged by the power provided by the external component 142 (e.g., via a transcutaneous energy transfer link). The transcutaneous energy transfer link is used to transfer power and / or data to the internal component 144 of the auditory prosthesis 100. Various types of energy transfer (e.g., infrared (IR), electromagnetic, capacitive, and inductive transfer) can be used to transfer power and / or data from the external component 142 to the internal component 144. During operation of the auditory prosthesis 100, the power stored by the rechargeable battery is distributed to various other implanted components as needed.

[0026] The internal component 144 includes an internal receiver unit 132, a stimulator unit 120, and an elongated electrode assembly 118. In some embodiments, the internal receiver unit 132 and the stimulator unit 120 are hermetically sealed within a biocompatible housing. The internal receiver unit 132 includes an internal coil 136 (e.g., a multi-turn wire antenna coil including electrically insulated single-strand or multi-strand platinum or gold wire), and preferably includes a magnet (also not shown) fixed relative to the internal coil 136. The internal receiver unit 132 and the stimulator unit 120 are hermetically sealed within a biocompatible housing, which is sometimes collectively referred to as the stimulator / receiver unit. The internal coil 136 receives power and / or data signals from an external coil 130 via a transcutaneous energy transfer link (e.g., an inductive RF link). The stimulator unit 120 generates an electrical stimulation signal based on the data signal, and the stimulation signal is delivered to the recipient via the elongated electrode assembly 118.

[0027] The elongated electrode assembly 118 has a proximal end connected to the stimulator unit 120 and a distal end implanted in the cochlea 140. The electrode assembly 118 extends from the stimulator unit 120 through the mastoid bone 119 to the cochlea 140. In some embodiments, the electrode assembly 118 may be implanted at least in the basal region 116 and sometimes deeper. For example, the electrode assembly 118 may extend towards the apex of the cochlea 140 (referred to as the cochlear apex 134). In certain cases, the electrode assembly 118 may be inserted into the cochlea 140 via a cochlear fenestra 122. In other cases, the cochlear fenestra may be formed through the round window 121, the oval window 112, the promontory 123, or through the apical turn 147 of the cochlea 140.

[0028] The elongated electrode assembly 118 includes a longitudinally aligned and distally extending array 146 of electrodes or contacts 148 disposed along its length, sometimes referred to herein as the electrode or contact array 146. Although the electrode array 146 may be disposed on the electrode assembly 118, in most practical applications, the electrode array 146 is integrated into the electrode assembly 118 (e.g., the electrode array 146 is disposed within the electrode assembly 118). As noted, the stimulator unit 120 generates a stimulation signal, which is applied to the cochlea 140 by the electrodes 148 to stimulate the auditory nerve 114.

[0029] Although FIG. 1A schematically shows a hearing prosthesis 100 that utilizes external components 142 including an external microphone 124, an external sound processing unit 126, and an external power source, in some other embodiments, one or more of the microphone 124, the sound processing unit 126, and the power source may be implanted on or within a recipient (e.g., within internal components 144). For example, the hearing prosthesis 100 may have each of a microphone 124, a sound processing unit 126, and a power source that are implantable on or within a recipient (e.g., encapsulated within a biocompatible assembly located subcutaneously), and may be referred to as a totally implantable cochlear implant (“TICI”). For another example, the hearing prosthesis 100 may have most of the components of a cochlear implant that are implantable on or within a recipient (e.g., excluding a microphone, which may be an in-ear canal microphone), and may be referred to as a mostly implantable cochlear implant (“MICI”).

[0030] FIG. 1B schematically shows a perspective view of an example fully implantable hearing prosthesis 200 (e.g., a fully implantable middle ear implant or a fully implantable acoustic system) utilizing an acoustic actuator in an implanted recipient, according to some embodiments described herein. The example hearing prosthesis 200 of FIG. 1B includes a biocompatible implantable assembly 202 (e.g., including an implantable capsule) located subcutaneously (e.g., beneath the recipient's skin and on the recipient's skull). Although FIG. 1B schematically shows an example implantable assembly 202 that includes a microphone, in other example hearing prostheses 200, a pendant microphone (e.g., connected to the implantable assembly 202 by a cable) may be used. The implantable assembly 202 includes a signal receiver 204 (e.g., including coil elements) and a sound transducer 206 (e.g., a microphone including a diaphragm and an electret or a piezoelectric transducer), the sound transducer being positioned to receive acoustic signals through the recipient's overlying tissue. The implantable assembly 202 may also be used to house a plurality of components of the fully implantable hearing prosthesis 200. For example, the implantable assembly 202 may include an energy storage device and a signal processor (e.g., a sound processing unit). Various additional processing logic and / or circuit system components may also be included in the implantable assembly 202 as a design option.

[0031] For the example auditory prosthesis 200 shown in FIG. 1B, the signal processor of the implantable component 202 operates in communication with an actuator 210 (e.g., including a transducer configured to generate mechanical vibrations in response to an electrical signal from the signal processor) (e.g., electrically interconnected via wire 208). In some embodiments, the example auditory prostheses 100, 200 shown in FIGS. 1A and 1B may include an implantable microphone assembly, such as microphone assembly 206 shown in FIG. 1B. For such example auditory prostheses 100, the signal processor of the implantable component 202 may operate in communication with the microphone assembly 206 and the stimulator unit of the main implantable component 120 (e.g., electrically interconnected via wires). In some embodiments, at least one of the microphone assembly 206 and the signal processor (e.g., the sound processing unit) is implanted on or within the recipient.

[0032] The actuator 210 of the example auditory prosthesis 200 shown in FIG. 1B is supportably connected to a positioning system 212, which in turn is connected (e.g., via a hole drilled through the skull) to a bone anchor 214 mounted within the mastoid of the recipient. The actuator 210 includes a connecting device 216 for connecting the actuator 210 to the recipient's ossicle 106. In the connected state, the connecting device 216 provides a communication path for acoustic stimulation of the ossicle 106 (e.g., by transmitting vibrations from the actuator 210 to the incus 109).

[0033] During normal operation, ambient acoustic signals (e.g., ambient sound) impinge on the recipient's tissue and are received transcutaneously at the microphone assembly 206. Upon receipt of the transcutaneous signal, the signal processor within the implantable component 202 processes the signal to provide a processed audio drive signal to the actuator 210 via wire 208. It will be appreciated that the signal processor may utilize digital processing techniques to provide frequency shaping, amplification, compression, and other signal conditioning, including adjustment based on recipient-specific fitting parameters. The audio drive signal causes the actuator 210 to transmit audio-frequency vibrations to the connecting device 216 to effect a desired sound perception via mechanical stimulation of the recipient's incus 109.

[0034] The subcutaneously implantable microphone assembly 202 is configured to respond to an acoustic signal (e.g., sound; pressure variations within the audible frequency range) by generating an output signal (e.g., an electrical signal; an optical signal; an electromagnetic signal), the output signal indicative of the acoustic signal received by the microphone assembly 202, and these output signals are used by the auditory prostheses 100, 200 to generate a stimulation signal that is provided to the recipient's auditory system. To compensate for the reduced acoustic signal strength reaching the microphone assembly 202 due to implantation, the diaphragm of the implantable microphone assembly 202 may be configured to provide a higher sensitivity than an external non-implantable microphone assembly. For example, the diaphragm of the implantable microphone assembly 202 may be configured to be more rigid and / or larger than the diaphragm used for an external non-implantable microphone assembly.

[0035] FIG. 1C schematically illustrates a portion of an exemplary transcutaneous bone conduction auditory prosthesis 300 implanted in a recipient in accordance with certain embodiments described herein. As schematically shown in FIG. 1C, the exemplary transcutaneous bone conduction auditory prosthesis 300 includes an external device 304 and an implantable component 306. The auditory prosthesis 300 is an active transcutaneous bone conduction auditory prosthesis because the vibration actuator 308 is located in the implantable component 306. For example, a vibration element in the form of the vibration actuator 308 is located in the housing 310 of the implantable component 306. In certain embodiments, the vibration actuator 308 is a device that converts an electrical signal into vibrations. The vibration actuator 308 may be in direct contact with the outer surface of the recipient's skull 196 (e.g., the vibration actuator 308 is in substantial contact with the recipient's bone 196 such that the vibratory force from the vibration actuator 308 is transmitted from the vibration actuator 308 to the recipient's bone 196). In certain embodiments, there may be one or more thin non-bony tissue layers (e.g., silicone layer 324) between the vibration actuator 308 and the recipient's bone 196 (e.g., bone tissue, skull) while still allowing sufficient support to permit the vibratory force generated by the vibration actuator 308 to be effectively transmitted to the recipient's bone 196.

[0036] In some embodiments, the external component 304 includes a sound input element 326 that converts sound into an electrical signal. Specifically, the auditory prosthesis 300 provides these electrical signals to the vibration actuator 308, or to a sound processor (not shown) that processes the electrical signals, and then provides these processed signals to the implantable component 306 via a magnetic induction link through the recipient's tissue (e.g., skin 190, fat 192, muscle 194). For example, the communication coil 332 of the external component 304 can transmit these signals to an implanted communication coil 334 located in the housing 336 of the implantable component 306. Components (not shown) in the housing 336, such as a signal generator or an implanted sound processor, then generate an electrical signal that will be delivered to the vibration actuator 308 via the electrical lead assembly 338. The vibration actuator 308 converts the electrical signal into vibrations. In some embodiments, the vibration actuator 308 can be positioned so close to the housing 336 that there is no electrical lead 338 (e.g., the housing 310 and the housing 336 are the same single housing that contains the vibration actuator 308, the communication coil 334, and other components such as a signal generator or a sound processor).

[0037] In some embodiments, the vibration actuator 308 is mechanically coupled to the housing 310. The housing 310 and the vibration actuator 308 together form a vibration element. The housing 310 can be attached to the bone fixation device 318 substantially rigidly.

[0038] In this regard, the housing 310 can include a through hole 320, the profile of which conforms to the outer profile of the bone fixation device 318. A screw 322 can be used to fix the housing 310 to the bone fixation device 318. As can be seen in FIG. 3, the head of the screw 322 is larger than the through hole 320 of the housing 310. Therefore, the screw 322 reliably holds the housing 310 to the bone fixation device 318. A portion of the screw 322 abuts the bone fixation device 318, thus allowing the screw 322 to be easily fitted into an existing bone fixation device 318 used in a percutaneous bone conduction device (or an existing passive bone conduction device). In some embodiments, the screw 322 is configured such that the same tools and procedures used to install a abutment screw and / or remove the abutment screw from the bone fixation device 318 can be used to install the screw 322 and / or remove the screw from the bone fixation device 318.

[0039] The bone fixation device 318 can be made of any material having a known ability to integrate into the surrounding bone tissue (e.g., including materials that exhibit acceptable bone integration characteristics). In some embodiments, the bone fixation device 318 is formed from a single piece of material (e.g., titanium) and includes an external thread and a flange, the external thread forming a male screw that is configured to be installed into the skull 196, and the flange being configured to act as a stop when the fixation device 318 is implanted into the skull 196. The thread can have a maximum diameter of about 3.5 mm to about 5.0 mm, and the flange can have a diameter that exceeds the maximum diameter of the thread (e.g., by more than about 10%-20%). The flange can have a flat bottom surface that is configured to abut the outer bone surface when the fixation device 318 has been screwed down into the skull 196. The flange prevents the fixation device 318 (e.g., the thread) from potentially completely penetrating the bone 196.

[0040] The body of the fixation device 318 can have a length sufficient to securely anchor the fixation device 318 to the skull 196 without completely penetrating the skull 196. Thus, the length of the body can depend on the thickness of the skull 196 at the implantation site. For example, the fixation device 318 can have a length measured from the flat bottom surface of the flange to the end of the distal region (e.g., the portion furthest from the flange) that is no greater than 5 mm or between about 3.0 mm and about 5.0 mm, which limits and / or prevents the possibility that the fixation device 318 might completely pass through the skull 196. The interior of the fixation device 318 can also include an inner lower hole having an internal thread that is configured to mate with the male thread of the screw 320 into the fixation device 318. The fixation device 318 can also include an inner upper hole that receives the bottom portion of the receiving pedestal 312.

[0041] FIG. 1D schematically illustrates a portion of an example auditory prosthesis 400 (e.g., a hearing aid) including a portion 410 (e.g., a housing) at least partially positioned within a recipient's ear canal 102. The hearing aid relies on the air conduction principle to transmit an amplified acoustic signal to the tympanic membrane 104, through the normal middle ear mechanism to the cochlea 140, thereby producing an enhanced perception of sound by the recipient. Typically, the hearing aid is positioned in the ear canal 102 or on the outer ear 110 to amplify the received sound. It is noted that hearing aids are commonly referred to in the industry as hearing instruments, and the receiver is the speaker that outputs sound to the recipient rather than the microphone. As schematically shown in FIG. 1D, the example auditory prosthesis 400 includes: at least one microphone 412 (e.g., positioned external to the ear or within the cavity of the outer ear 101 or auricle 110, as schematically shown in FIG. 1D), the at least one microphone being configured to receive ambient sound 103; a sound processing circuitry 414; and at least one speaker 416 (e.g., positioned within the ear canal 102, as schematically shown in FIG. 1D), the at least one speaker being configured to generate an acoustic signal (e.g., an amplified sound), the acoustic signal being transmitted to the tympanic membrane 104.

[0042] The example auditory prosthesis 100 shown in FIG. 1A utilizes an external microphone 124, the auditory prosthesis 200 shown in FIG. 1B utilizes an implantable microphone assembly 206 including a percutaneous implantable acoustic transducer, the example transcutaneous bone conduction auditory prosthesis 300 of FIG. 1C includes an external sound input element 326 (e.g., an external microphone), and the in-ear hearing aid 400 includes an external microphone 412. In certain embodiments described herein, a percutaneous implantable sound input component (e.g., an implantable microphone) is used with the auditory prostheses 100, 200, 300, 400, and / or one or more external microphone components are used with the auditory prostheses 100, 200, 300, 400. In certain embodiments, the external microphone component can be used to supplement the implantable microphone component of the auditory prostheses 100, 200, 300, 400. Thus, the teachings detailed herein and / or variations thereof can be used with any type of external and / or implantable microphone arrangement, and the auditory prostheses 100, 200, 300, 400 shown in FIGS. 1A - 1D are merely illustrative.

[0043] During the operation of a hearing prosthesis, there are limited options for automatic measurement, diagnosis, and / or troubleshooting. As a result, changes in performance (e.g., gradual changes, such as the accumulation of contaminants on the microphone protection material, which may not be very noticeable to the recipient) may develop to an acoustically significant level before the problem is noticed and corrected. Certain embodiments described herein provide for a fully or partially automated test that can be run by the hearing prosthesis of a bilateral acoustic prosthesis system, where the characteristics of sounds from the surrounding environment detected by at least two microphones (e.g., at least one microphone of each of the two hearing prostheses; at least two microphones of one of the two hearing prostheses) are compared to each other. This test can be performed between the fitting process and / or an examination of the acoustic prosthesis by a medical practitioner (e.g., a clinician). By monitoring the changes in the differences in these characteristics over time, problems in at least one of the acoustic prostheses can be detected. This information can be relayed to the recipient and / or the medical practitioner and can be used to trigger further troubleshooting (e.g., replacing the microphone cap or scheduling a fitting process).

[0044] Certain embodiments described herein provide for better hearing performance (e.g., more quickly identifying and correcting a decrease in hearing performance), a more efficient remote fitting process (e.g., by providing more detailed information about the device function for consultation or troubleshooting), a reduced need for an in-person fitting process (e.g., thereby improving convenience and clinical efficiency by reducing the time spent by the clinician with each recipient), and / or greater confidence in the proper operation of the acoustic prosthesis system.

[0045] Figures 2A and 2B schematically illustrate two example devices 500 in accordance with certain embodiments described herein. Figure 2C schematically illustrates an example information flow diagram in accordance with two example devices 500 in accordance with certain embodiments described herein. The device 500 includes at least one first transducer 510 (e.g., a microphone), the at least one transducer being configured to be worn on or within the body of a recipient. The at least one first transducer 510 is configured to generate a transducer signal 512 (e.g., a microphone signal), the transducer signal indicative of an environmental sensory excitation 503 (e.g., environmental sound 103; not shown in Figures 2A and 2B) from the recipient's environment. The device 500 further includes a first circuitry 520, the first circuitry being configured to receive the transducer signal 512 and, in response to the transducer signal 512, generate a stimulation signal 522, the stimulation signal being configured to be received by the recipient's body to evoke a sensory (e.g., hearing) perception of the recipient. The stimulation signal 522 is indicative of the environmental sensory excitation 503. The device 500 further includes a second circuitry 530, the second circuitry being configured to generate first data 532a indicative of a first comparison of a response of the at least one first transducer 510 to the environmental sensory excitation 503 (e.g., first information 514a) at a first time t1 with a response of at least one second transducer 610 (e.g., a microphone) to the environmental sensory excitation 503 (e.g., second information 614a) at the first time t1. The second circuitry 530 is further configured to generate second data 532b indicative of a second comparison of a response of the at least one first transducer 510 to the environmental sensory excitation 503 (e.g., first information 514b) at a second time t2 with a response of at least one second transducer 610 of the device 600 to the environmental sensory excitation 503 (e.g., second information 614b) at the second time t2. The second time t2 is after the first time t1. The second circuitry 530 is further configured to generate a performance assessment 534 of at least one aspect of the device 500 in response to a third comparison of the first data 532a with the second data 532b.

[0046] In certain embodiments, the at least one first transducer 510 and the first circuitry 520 (e.g., a first stimulation circuitry) are components of a first sensory (e.g., auditory) prosthesis that is operably communicable with a first sensory subsystem of the recipient (e.g., a first ear), and the at least one second transducer 610 is a component of a second sensory (e.g., auditory) prosthesis that is operably communicable with a second sensory subsystem of the recipient (e.g., a second ear). For example, the first auditory prosthesis and the second auditory prosthesis may be parts of a binaural or bilateral auditory prosthesis system implanted in and / or worn by the recipient.

[0047] In some embodiments, at least one first transducer 510 and at least one second transducer 610 are components of the same device 500 (e.g., an implantable microphone or a non-implantable microphone of a single acoustic prosthesis). In some other embodiments, at least one second transducer 610 is a component of a device 600 separate from the device 500 that includes at least one first transducer 510. As schematically shown in FIGS. 2A and 2B, the device 600 may include: at least one second transducer 610 (e.g., a microphone), the at least one second transducer being configured to generate a second transducer signal 612 that indicates an environmental sensory stimulus 503 from the recipient's environment; and a second stimulation circuitry 620, the second stimulation circuitry being configured to receive the second transducer signal 612 and, in response to the second transducer signal 612, generate a second stimulation signal 622 that is configured to be received by the recipient's body to evoke a sensory (e.g., hearing) perception of the recipient. Both the stimulation signal 522 and the second stimulation signal 622 may indicate the environmental sensory stimulus 503. More specifically, a first sensory prosthesis (e.g., a first auditory prosthesis) and a second sensory prosthesis (e.g., a second auditory prosthesis) respectively generate a first information 514a and a second information 614a that indicate the same environmental sensory stimulus 503 from the recipient's environment at a first time t1, and respectively generate a first information 514b and a second information 614b that indicate the same environmental sensory stimulus 503 from the recipient's environment at a second time t2.

[0048] In some embodiments, at least one first transducer 510 and at least one second transducer 610 each include an active component that responds to a sensory stimulus from the surrounding environment. Although at least one first transducer 510 and at least one second transducer 610 are described herein as microphones that are components of an auditory prosthesis, at least one first transducer 510 and at least one second transducer 610 may be components of other types of sensory prostheses. For example, the environmental sensory stimulus 503 may be acceleration (e.g., at least one first transducer 510 and at least one second transducer 610 each include an accelerometer for a vestibular implant). As another example, the environmental sensory stimulus 503 may be visual color / brightness data (e.g., at least one first transducer 510 and at least one second transducer 610 each include a camera for a visual implant). In some embodiments, at least one first transducer 510 and at least one second transducer 610 may be components of a monitoring device configured to measure an environmental signal that is not used to stimulate the recipient's body. For example, at least one first transducer 510 and at least one second transducer 610 may each include a sensor configured to measure a signal (e.g., heart rate; blood pressure; blood glucose level; respiratory rate) from the recipient's body that is to be recorded (e.g., stored).

[0049] In certain embodiments, the first sensory prosthesis and / or the second sensory prosthesis includes a cochlear implant (e.g., auditory prosthesis 100) configured to provide a stimulation signal 522, 622 (e.g., an electrical signal) to a corresponding cochlea 140 of a recipient (see, e.g., FIG. 1A). In certain embodiments, the first sensory prosthesis and / or the second sensory prosthesis includes a fully implantable sensory prosthesis (e.g., auditory prosthesis 200 including an acoustic actuator 210) configured to provide a stimulation signal 522, 622 (e.g., a vibration signal) to a corresponding ossicle 106 of a recipient (e.g., malleus 108; incus 109; stapes 111) (see, e.g., FIG. 1B). In certain embodiments, the first sensory prosthesis and / or the second sensory prosthesis includes a bone conduction auditory prosthesis (e.g., auditory prosthesis 300) configured to provide a stimulation signal 522, 622 (e.g., a vibration signal) to a corresponding temporal bone portion 115 of a recipient (see, e.g., FIG. 1C). In certain embodiments, the first sensory prosthesis and / or the second sensory prosthesis includes a hearing aid (e.g., auditory prosthesis 400) configured to provide a stimulation signal 522, 622 (e.g., an amplified sound signal) to a corresponding tympanic membrane 104 of a recipient.

[0050] In certain embodiments, the first sensory prosthesis and the second sensory prosthesis are the same type of sensory prosthesis (e.g., both are cochlear implants; both have acoustic actuators; both are bone conduction devices; both are hearing aids), while in certain other embodiments, the first sensory prosthesis and the second sensory prosthesis are different types of sensory prostheses but respond to the same environmental sensory stimuli (e.g., a bimodal system, an example of which is a hearing aid on one ear and a cochlear implant on the other ear). In certain embodiments, both the at least one first transducer 510 and the at least one second transducer 610 are in operative communication with the same sensory prosthesis (e.g., the first transducer 510 includes an implantable microphone and the second transducer 610 includes an external microphone), while in certain other embodiments, the at least one first transducer 510 is a component of the first sensory prosthesis and the at least one second transducer 610 is a component of a second sensory prosthesis different from the first sensory prosthesis. In certain embodiments, the first sensory prosthesis and the second sensory prosthesis are worn on opposite ears or within opposite ears of the recipient's body, while in certain other embodiments, the first sensory prosthesis and the second sensory prosthesis are worn on the same ear or within the same ear of the recipient's body.

[0051] In some embodiments, the first circuitry 520 includes at least one microcontroller, which may include at least one application specific integrated circuit (ASIC) microcontroller, a digital signal processing (DSP) microcontroller, a general integrated circuit programmed with computer-executable instructions, and / or a microcontroller core. The first circuitry 520 of some embodiments is a component of a sensory processing unit (e.g., the sound processing unit 126) of a first sensory prosthesis. For example, the sound processing unit 126 of FIG. 1A is a behind-the-ear (BTE) sound processing unit configured to be attached to and worn adjacent to the ear of a recipient. However, in some other embodiments, the sensory processing unit has other arrangements, such as through an over-the-ear (OTE) processing unit (e.g., a component having a generally cylindrical shape and configured to be magnetically coupled to the head of the recipient), a mini or micro BTE unit, an in-the-ear canal unit configured to be located within the ear canal 102 of the recipient, a body-worn sensory processing unit, etc. Thus, the first circuitry 520 and the second stimulation circuitry 620 generate first information 514a, b and second information 614a, b, respectively, both the first information and the second information indicating the same environmental sensory stimulus 503 (e.g., environmental sound 103) from the recipient's environment.

[0052] In some embodiments, the second circuitry 530 includes at least one microcontroller, which may include at least one application specific integrated circuit (ASIC) microcontroller, a digital signal processing (DSP) microcontroller, a general integrated circuit programmed with software having computer-executable instructions, and / or a microcontroller core. In some embodiments, the second circuitry 530 and the first circuitry 520 include different portions of the same circuitry (e.g., a single microcontroller), while in some other embodiments, the second circuitry 530 and the first circuitry 520 include portions of different microcontrollers. In some embodiments, the second circuitry 530 includes a storage circuitry and / or operates in communication with a storage circuitry, which is configured to store information (e.g., data; commands) accessed by the second circuitry 530 during operation (e.g., when providing the functionality of some embodiments described herein). The storage circuitry may include at least one tangible (e.g., non-transitory) computer-readable storage medium, examples of which include but are not limited to: read only memory (ROM); random access memory (RAM); disk storage media; optical storage media; flash memory. The storage circuitry may be encoded with software (e.g., a computer program downloaded as an application), the software including computer-executable instructions for instructing the second circuitry 530 (e.g., executable data access logic, evaluation logic, and / or information output logic). In some embodiments, the second circuitry 530 executes the instructions of the software to provide the functionality described herein. The second circuitry 530 of some embodiments also includes other digital circuitry (e.g., registers; filters; output controllers; memory controllers).

[0053] In some embodiments, as schematically shown in FIG. 2A, the second circuitry 530 is a component of the first sensory prosthesis and is in electrical communication with at least one first transducer 510 to receive information (e.g., transducer signal 512 from at least one first transducer 510). In some other embodiments, the second circuitry 530 receives information from the first circuitry 520. The second circuitry 530 also communicates wirelessly with a device 600 (e.g., a second sensory prosthesis) and is configured to receive information 614 (e.g., wireless signal 624) from the device 600, the wireless signal 624 indicating a second transducer signal 612. For example, the first sensory prosthesis and the second sensory prosthesis may each include communication circuitry configured to form a wireless data link (e.g., WiFi; Bluetooth; cellular connection; telephone; or other Internet connection) through which the wireless signal 624 is transmitted from the device 600 to the second circuitry 530. In some other embodiments, the first sensory prosthesis and the second sensory prosthesis communicate with each other wireline (e.g., a signal indicating the second transducer signal 612 is transmitted from the device 600 to the second circuitry 530 through a wire). For example, the first sensory prosthesis and the second sensory prosthesis may be part of a non-surgical bimodal hearing system including a single head-mounted device that includes at least one first transducer 510 and at least one second transducer 610 on substantially opposite sides of the recipient's head.

[0054] In some embodiments (see, e.g., FIG. 2A), the second circuitry 530 is configured to generate first data 532a by receiving a first portion of the transducer signal 512 (e.g., first information 514a; a microphone signal generated in response to ambient sound 103 at a first time t1), and receiving a first portion of the wireless signal 624 (e.g., second information 614a; second transducer signal 612) indicating the response of at least one second transducer 610 at the first time t1 (e.g., a microphone signal generated in response to ambient sound 103 at the first time t1). Similarly, the second circuitry 530 may be configured to generate second data 532b by receiving a second portion of the transducer signal 512 (e.g., first information 514b; a microphone signal generated in response to ambient sound 103 at a second time t2), and receiving a second portion of the wireless signal 624 (e.g., second information 614b; second transducer signal 612) indicating the response of at least one second transducer 610 at the second time t2 (e.g., a microphone signal generated in response to ambient sound 103 at the second time t2).

[0055] In certain other embodiments, as schematically shown in FIG. 2B, the second circuitry 530 is a component of a device 650 (e.g., a smart phone, a smart tablet, a smart watch, a computer, or other remote device operated by a recipient and / or a practicing physician such as a clinician), the device being separate from but in communication with both the first sensory prosthesis and the second sensory prosthesis. For example, the device 650 may include communication circuitry configured to wirelessly receive a first portion of first information 514a,b (e.g., a first portion of the wireless signal 524) from the first sensory prosthesis and a second portion of second information 614a,b (e.g., a second portion of the wireless signal 624) from the second sensory prosthesis. The communication circuitry of the device 650 and the communication circuitry of the first sensory prosthesis may form a first wireless data link (e.g., WiFi; Bluetooth; cellular connection; telephone; or other Internet connection) through which the wireless signal 524 indicative of the transducer signal 512 is transmitted from the first sensory prosthesis to the second circuitry 530. Additionally, the communication circuitry of the device 650 and the communication circuitry of the second sensory prosthesis may form a second wireless data link (e.g., WiFi; Bluetooth; cellular connection; telephone; or other Internet connection) through which the wireless signal 624 is transmitted from the device 600 to the second circuitry 530.

[0056] In certain embodiments (see, e.g., FIG. 2B), the second circuitry 530 is configured to receive a first portion of information 514a (e.g., the wireless signal 524) indicative of a response of the first sensory prosthesis during a first time period, receive a second portion of information 614a (e.g., the wireless signal 624) indicative of a response of the second sensory prosthesis, and generate a first comparison (e.g., first data 532a) of these first portions 514a, 614a. The second circuitry 530 may also be configured to receive a second portion of information 514b (e.g., the wireless signal 524) indicative of a response of the first sensory prosthesis during a second time period, receive a second portion of information 614b (e.g., the wireless signal 624) indicative of a response of the second sensory prosthesis, and generate a second comparison (e.g., second data 532b) of these second portions 514b, 614b.

[0057] The first data 532a generated by the second circuitry 530 may indicate a first frequency response difference and / or a first sensitivity difference between at least one first transducer 510 and at least one second transducer 610. Similarly, the second data 532b generated by the second circuitry 530 may indicate a second frequency response difference and / or a second sensitivity difference between at least one first transducer 510 and at least one second transducer 610.

[0058] For example, at time t n the frequency response difference at can be the frequency response R1(t n of at least one first transducer 510 to the environmental sensing excitation 503 at time t n (e.g., the distribution of acoustic frequencies detected by at least one first microphone at time t n ) and the frequency response R2(t n of at least one second transducer 610 to the same environmental sensing excitation 503 at time t n (e.g., the distribution of acoustic frequencies detected by at least one second microphone at time t n ). As another example, the first sensitivity difference at time t n can be the sensitivity S1(t n of at least one first transducer 510 to the environmental sensing excitation 503 at time t n (e.g., the amplitude detected by at least one first microphone for the environmental sound 103 at one or more predetermined acoustic frequencies at time t n ) and the sensitivity S2(t n of at least one second transducer 610 to the same environmental sensing excitation at time t n (e.g., the amplitude detected by at least one second microphone for the same environmental sound 103 at one or more predetermined acoustic frequencies at time t n ).

[0059] In certain embodiments, the second circuitry 530 is configured to evaluate whether the environmental sensory stimulus 503 at a first time t1 is sufficient to generate the first data 532a before generating the first data 532a. For example, the second circuitry 530 may evaluate whether the environmental sound 103 at the first time t1 has sufficient amplitude and / or acoustic frequency range (e.g., sufficient amplitude at each frequency of a predetermined set of frequency ranges; loud enough over a wide enough frequency range) to generate the first data 532a. Similarly, in certain embodiments, the second circuitry 530 is configured to evaluate whether the environmental sensory stimulus 503 at a second time t2 is sufficient to generate the second data 532b before generating the second data 532b. For example, the second circuitry 530 may evaluate whether the environmental sound 103 at the second time t2 has sufficient amplitude and / or acoustic frequency range (e.g., sufficient amplitude at each frequency of a predetermined set of frequency ranges; loud enough over a wide enough frequency range) to generate the second data 532b. If the amplitude and / or acoustic frequency range at the first time t1 is sufficient (e.g., greater than one or more predetermined thresholds), then the second circuitry 530 may continue to generate the first data 532a. If the amplitude and / or acoustic frequency range at the first time t1 is insufficient (e.g., less than one or more predetermined thresholds), then the second circuitry 530 stops the data generation process and may generate a warning signal (e.g., light; sound; text; image) to be received by the recipient and / or the practitioner. Similarly, if the amplitude and / or acoustic frequency range at the second time t2 is sufficient (e.g., greater than one or more predetermined thresholds), then the second circuitry 530 may continue to generate the second data 532b. If the amplitude and / or acoustic frequency range at the second time t2 is insufficient (e.g., less than one or more predetermined thresholds), then the second circuitry 530 stops the data generation process and may generate a warning signal (e.g., light; sound; text; image) to be received by the recipient and / or the practitioner.

[0060] In certain embodiments, the second circuitry 530 is configured to generate the first data 532a upon receiving a first trigger signal. For example, the first trigger signal may include a first user input signal (e.g., via a button, touch screen, or other user interface) that indicates a first command from the recipient and / or the practitioner to receive the first information 514a and the second information 614a at a first time t1 and generate the first data 532a. The first trigger signal may be received by the second circuitry 530 during an adaptation process in which the performance of the first and second sensory prostheses is optimized by the practitioner for the recipient.

[0061] In response to the first trigger signal, the second circuit system 530 may sample the response of at least one first transducer 510 to the environmental sensing excitation 503 at the first time t1, sample the response of at least one second transducer 610 to the same environmental sensing excitation 503 at the first time t1, and calculate first data 532a, which includes a first frequency response difference (e.g., Δ R1 =|R1(t1)-R2(t1)|) and / or a first sensitivity difference (e.g., Δ S1 =|S1(t1)-S2(t1)|) at the first time t1. The second circuit system 530 may be configured to store the first information 514a, the second information 614a, and / or the first data 532a when generating the first data 532a for later retrieval for performance evaluation.

[0062] In some embodiments, the second circuitry 530 is configured to generate second data 532b upon receiving a second trigger signal. For example, the second trigger signal may include a second user input signal (e.g., via a button, touch screen, or other user interface) that indicates a first command from a recipient and / or a healthcare practitioner to receive first information 514a and second information 614a at a second time t2 (after t1) and to generate second data 532b. The second trigger signal may be generated by the recipient and / or healthcare practitioner during a subsequent fitting procedure or at any other time when the recipient and / or healthcare practitioner deems a performance evaluation necessary, in which the performance of the first and second sensory prostheses is optimized by the healthcare practitioner for the recipient. As another example, the second trigger signal may include a clock signal that indicates a planned time interval (e.g., one day or several days; one week or several weeks; one month or several months) has elapsed after first data 532a was generated at the first time t1. As another example, the second trigger signal may include a transducer signal (e.g., from at least one first transducer 510 and / or at least one second transducer 610) that indicates the environmental sensory excitation at the second time t2 has a predetermined property (e.g., an abnormal amplitude and / or an acoustic frequency range). The predetermined property may be determined by a machine learning circuitry of the first sensory prosthesis, a machine learning circuitry of the second sensory prosthesis, and / or a machine learning circuitry of the device 650. As another example, the second trigger signal may include a signal generated by a circuitry of the first sensory prosthesis and / or the second sensory prosthesis (e.g., the first circuitry 520; the second stimulation circuitry 620) that indicates a difference between responses of a plurality of transducers (e.g., different microphones of the same acoustic prosthesis) of the first sensory prosthesis and / or the second sensory prosthesis. As another example, the second trigger signal may include a sensor signal that indicates a condition that may damage at least one first transducer 510 and / or at least one second transducer 610. The sensor signal may be provided by a sensor of the first sensory prosthesis and / or the second sensory prosthesis (e.g., an accelerometer that responds to a fall or impact experienced by the recipient; a thermal sensor that responds to overheating and / or overcooling temperatures). As another example, the second trigger signal may be generated by a hardware reset of a circuitry of the first sensory prosthesis and / or the second sensory prosthesis.

[0063] In response to the second trigger signal, the second circuitry 530 may sample the response of at least one first transducer 510 to the environmental sensory excitation 503 at the second time t2, sample the response of at least one second transducer 610 to the same environmental sensory excitation 503 at the second time t2, and compute second data 532b, which includes a second frequency response difference at the second time t2 (e.g., Δ R2= |R1(t2) - R2(t2)|) and / or a second sensitivity difference at a second time t2 (e.g., Δ S2 = |S1(t2) - S2(t2)|). The second circuit system 530 can be configured to store the first information 514b, the second information 614b, and / or the second data 532b when generating the second data 532b for later retrieval and comparison with additional data.

[0064] In some embodiments, the performance evaluation 534 of at least one aspect of the device 500 (e.g., at least one transducer 510, the first circuit system 520, at least one second transducer 610, and / or the second stimulation circuit system 620) includes comparing the first data 532a with the second data 532b. For example, the second circuit system 530 can retrieve the first data 532a from the storage circuit system and then compare the retrieved first data 532a with the second data 532b.

[0065] In some embodiments, the comparison of the first data 532a with the second data 532b indicates the difference between the first data 532a and the second data 532b (e.g., Δ R = |Δ R1 -Δ R2 |; Δ S = |Δ S1 –Δ S2 |), and this difference is compared with a predetermined threshold. If the difference is less than the threshold, the second circuit system 530 of some embodiments (e.g., using light, sound, text, and / or image) provides a notification to the recipient and / or the practicing physician that the performance evaluation has not detected a problem that requires further troubleshooting and / or investigation. Other example responses of the second circuit system 530 to the difference being less than the threshold include, but are not limited to, taking no action. If the difference is greater than the threshold, the second circuit system 530 of some embodiments (e.g., using light, sound, text, and / or image) provides a notification that a problem that requires further troubleshooting has been detected. Other example responses of the second circuit system 530 to the difference being greater than the threshold include, but are not limited to: sending the first data 532a and / or the second data 532b to the practicing physician; arranging an adaptation process for the recipient and the practicing physician; describing other actions to be taken (e.g., replacing or cleaning the microphone cover).

[0066] In some embodiments, the predetermined threshold includes a static threshold (e.g., in dB, for each frequency in a predetermined frequency range). The predetermined threshold can be defined per unit time for a particular combination of sensory prostheses. For example, if a first sensory prosthesis decreases in sensitivity more slowly than a second sensory prosthesis, the difference in sensitivity will gradually increase over time, and the threshold can be defined in dB / month or dB / year. In some embodiments, the predetermined threshold (e.g., when collecting data from the device in the field) includes a dynamic threshold that is configured to be adjusted over time. For example, machine learning or statistical models can be used to receive the performance of a number of acceptable and unacceptable devices (e.g., including those returned for repair due to damage), and output a suitable threshold to be used.

[0067] Figures 3A and 3B are flowcharts of example methods 700a, b for performing an initial test at time t n (e.g., n = 1) and a subsequent test at time t m (e.g., m > n) in the performance evaluation of a sensory prosthesis system (e.g., a bilateral acoustic prosthesis system), respectively, according to some embodiments described herein. For example, the initial test at time t n can be the first test ever performed on the sensory prosthesis system (e.g., as part of a fitting or programming procedure for the sensory prosthesis system at a practitioner's site under controlled conditions), and the subsequent test at time t m can be a "field" test performed during normal operation of the sensory prosthesis system (e.g., a test performed under uncontrolled conditions). As another example, the initial test at time t n can be performed during normal operation of the sensory prosthesis system (e.g., a test performed under uncontrolled conditions), and the subsequent test at time t m can be later than the initial test and performed during normal operation of the sensory prosthesis system (e.g., performed under uncontrolled conditions). Figure 4 is a flowchart of an example method 800 for detecting performance degradation in one of a first sensory prosthesis and a second sensory prosthesis of a sensory prosthesis system (e.g., a bilateral acoustic prosthesis system) according to some embodiments described herein.

[0068] Although example methods 700a, b, 800 are described herein with reference to the example device 500 of FIGS. 2A-2B, other devices are also compatible with example methods 700a, b, 800 according to some embodiments described herein. For example, the methods 700a, b, 800 described herein can be applied to any of a variety of sensory prosthesis systems having multiple transducers.

[0069] In operation block 710a, method 700a includes initiating an initial test. For example, the initial test can be initiated in response to a first trigger signal from a user (e.g., a recipient and / or a healthcare practitioner), or in response to a first automated trigger signal (e.g., generated by a second circuitry 530 as part of an adaptation or programming procedure of the sensory prosthesis system). In some embodiments where the initial test is performed as part of an adaptation or programming procedure of the sensory prosthesis system (e.g., at a healthcare practitioner's site), initiating the initial test can further include emitting a predetermined sensory stimulus into the surrounding environment (e.g., a sound from a speaker) for detection by at least one first transducer 510 and at least one second transducer 620. To improve effectiveness, the predetermined sound can be delivered in a prescribed manner. For example, the predetermined sound can be delivered from a speaker that is equidistant from both at least one first transducer 510 and at least one second transducer 610, such that variations in the measured values (e.g., in operation block 730a) are due to differences between at least one first transducer 510 and at least one second transducer 610 and / or the sensory prosthesis, rather than due to differences in the distance between the speaker and at least one first transducer 510 and at least one second transducer 610.

[0070] In operation block 720a, method 700a further includes evaluating whether an ambient sensory stimulus (e.g., ambient sound) is suitable for use in the initial test against predetermined suitability criteria. Examples of the predetermined suitability criteria include, but are not limited to: broadband power level (e.g., not too low or not too high); shape of the spectrum; associated metadata for understanding the suitability of the ambient sound environment (e.g., scene classifier state; directionality of the signal); data from additional sensors (e.g., accelerometer data for determining whether the recipient's head is moving). For example, the ambient sound can be evaluated by comparing the ambient sound detected by at least one first transducer 510 (e.g., a microphone) and / or at least one second transducer 610 (e.g., a microphone) with a predetermined threshold of sufficient amplitude and / or acoustic frequency range. If the ambient sound is evaluated as suitable (e.g., the amplitude and / or acoustic frequency range at time t n is greater than the corresponding predetermined threshold), then the initial test can proceed. If the ambient sound is evaluated as not suitable (e.g., the amplitude and / or acoustic frequency range at time t n is less than the corresponding predetermined threshold), then the initial test can be paused, and the ambient sound can continue to be monitored and evaluated until the ambient sound meets the suitability criteria, and then the initial test can proceed.

[0071] In operation block 730a, method 700a further includes measuring the ambient sensory stimulus at time t n using at least one first transducer 510 and using at least one second transducer 620. Time tn The measurement at indicates the response of transducers 510, 610 to the same ambient sensory excitation received by transducers 510, 610 at time t n In operation block 740a, method 700a also includes analyzing the measurement at time t n to determine the characteristics of the response of transducers 510, 610 (e.g., frequency response; sensitivity). In some embodiments, each measurement is analyzed by the sensory prosthesis performing the measurement, while in some other embodiments, both measurements are analyzed by the same sensory prosthesis and / or by a separate device 650. In operation block 750a, method 700a also includes measuring and storing the comparison of the transducer responses at time t n (e.g., a first difference value between the characteristics of the responses of transducers 510, 610 at time t n ).

[0072] To perform a subsequent test at time t m (e.g., m > n), in operation block 710b, method 700b includes initiating a subsequent test. For example, the subsequent test can be initiated in response to a second trigger signal from a user (e.g., the recipient and / or a healthcare practitioner) or in response to a second automated trigger signal. The second automated trigger signal can be automatically generated by a second circuitry 530 in response to at least one of the following: a predetermined amount of time elapsed since time t n ; detection of a potentially harmful event (e.g., device shock detected by an accelerometer; temperature extremes detected by a thermal sensor); detection of a change in comparison data between multiple transducers within a single sensory prosthesis. Unlike the initial test, the subsequent test in some embodiments does not use any predetermined sensory excitation.

[0073] In operation block 720b, method 700b also includes evaluating whether the ambient sensory stimulus is suitable for use in the subsequent test against a predetermined suitability criterion. For example, similar to the evaluation in operation block 720a, the ambient sound can be evaluated by comparing the ambient sound detected by at least one first transducer 510 (e.g., a microphone) and / or at least one second transducer 610 (e.g., a microphone) with a predetermined threshold of sufficient amplitude and / or acoustic frequency range. If the ambient sound is evaluated as suitable (e.g., the amplitude and / or acoustic frequency range at time t m is greater than the corresponding predetermined threshold), then the subsequent test can proceed. If the ambient sound is evaluated as unsuitable (e.g., the amplitude and / or acoustic frequency range at time t m is less than the corresponding predetermined threshold), then the subsequent test can be paused, and the ambient sound can continue to be monitored and evaluated until the ambient sound meets the suitability criterion, and then the subsequent initial test can be continued.

[0074] In operation block 730b, method 700b further includes measuring an ambient sensory stimulus at time t m using at least one first transducer 510 and using at least one second transducer 620. The measured value at time t m indicates the response of transducers 510, 610 to the same ambient sensory excitation received by transducers 510, 610 at time t m In operation block 740b, method 700b further includes analyzing the measured value at time t m to determine characteristics (e.g., frequency response; sensitivity) of the response of transducers 510, 610. In some embodiments, each measured value is analyzed by the sensory prosthesis performing the measurement, while in some other embodiments, both measured values are analyzed by the same sensory prosthesis and / or by a separate device 650. In operation block 750b, method 700b further includes measuring and storing a comparison of the transducer responses at time t m e.g., a second difference value between the characteristics of the responses of transducers 510, 610 at time t m

[0075] In operation block 810, method 800 includes comparing a first difference value (e.g., measured and stored previously during operation block 750a) with a second difference value (e.g., measured and stored previously during operation block 750b). For example, the difference between the first difference value and the second difference value can be calculated (e.g., the absolute value of the difference). In some embodiments where short-term changes in the ambient sound environment (e.g., sounds from one side of the recipient) may interfere with this comparison, for compensation, each measured value can be defined as the average of data collected by the transducer over a certain period (e.g., several hours).

[0076] In operation block 820, method 800 further includes determining whether the calculated difference between the first difference value and the second difference value is greater than a predetermined threshold. Depending on how the threshold is defined, the calculated difference value can be compared in various ways. For example, the most recent measured value C n can be compared with the initial measured value C0, which can be used to identify a gradual drift over time. As another example, the most recent measured value C n can be compared with the previous measured value C n-1 which can be used to identify a relatively sudden change in performance. As another example, the most recent measured value C n can be compared with a trend line established from all or several of the measured values from C0 to C n-1 which can be used (e.g., using the gradient of the curve) to identify a trend even if the performance has not deteriorated to the extent of reaching a single defined threshold.

[0077] ​According to certain embodiments described herein, a predetermined threshold can be determined in various ways. For example, the predetermined threshold can be a statically defined threshold (e.g., in dB for each frequency in a frequency range). As another example, the predetermined threshold can be a statically defined threshold defined per unit of time (e.g., in dB / month or dB / year). Such thresholds can be used for specific combinations of sensory prostheses with different rates of sensitivity degradation, which can result in a gradual difference in sensitivity over time. As another example, the predetermined threshold can be a dynamically defined threshold (e.g., adjusted over time when the manufacturer collects data from the device in the field). Such a dynamically defined threshold can be the output of machine learning or statistical modeling that takes as input the performance of many acceptable and unacceptable devices (e.g., including those returned for repair due to damage). As another example, the predetermined threshold can be a dynamically defined threshold that depends on the combination of devices used in the comparison (e.g., whether the devices are on the same side of the head). As another example, the predetermined threshold can be a dynamically defined threshold that depends on previous clinical tests (e.g., if the algorithm for a particular recipient indicates many false alarms in the absence of an actual hardware problem, the threshold can be increased).

[0078] If the calculated difference is greater than the predetermined threshold, method 800 further includes generating a report signal indicating that a performance degradation has been detected in operation block 830. If the calculated difference is not greater than the predetermined threshold, method 800 further includes generating a report signal indicating that no performance degradation has been detected in operation block 840.

[0079] In some embodiments, multiple comparisons can be performed during each performance assessment. A performance degradation detected by any one performance assessment can indicate a problem with transducer 510, 610, and / or at least one of the first and second sensory prostheses, and can be used to initiate further testing and / or investigation. If at least one prosthesis includes more than one transducer (e.g., a microphone), the multiple comparisons can include comparisons of different combinations of transducers (e.g., comparing the first microphone of the first prosthesis with the first microphone of the second prosthesis; comparing the second microphone of the first prosthesis with the first microphone of the second prosthesis; etc.). If there are two or more prostheses in the system, at least one of which has multiple transducers (e.g., the recipient has a left cochlear implant and a right hearing aid, the left cochlear implant has an implanted microphone and a left sound processor and an external microphone), and there is a non-prosthesis device in the system that has a transducer (e.g., a microphone) (e.g., a smartphone), the multiple comparisons can include comparing the first microphone of the first prosthesis with the first microphone of the second prosthesis; comparing the first microphone of the first prosthesis with the first microphone of the non-prosthesis device; etc. In some embodiments where not all comparisons are equivalent (e.g., a comparison between an implanted microphone and a non-implanted microphone on the same side of the recipient's head that is not affected by the direction from which ambient sound is received), weighting can be applied such that certain combinations of devices have a greater impact on the overall assessment.

[0080] In some embodiments, a transformation function can be applied to the measurements from one of the devices, the transformation function depending on the type of device to be compared. For example, due to the tissue layer coverage, an implanted microphone may experience a different acoustic environment than a non-implanted microphone. The transformation function can be applied to the measurements of one of the devices (e.g., the implanted microphone) before performing the comparison in order to better match the data output by the other device.

[0081] Although, for ease of understanding, common terms are used to describe the systems and methods of certain embodiments, these terms are used herein with their broadest reasonable interpretation. Although aspects of the present disclosure are described with reference to exemplary examples and embodiments, the disclosed examples and embodiments should not be construed as limiting. Unless otherwise specifically stated, or as otherwise understood in the context in which it is used, conditional language such as "can," "could," "might," or "may" generally is intended to convey that a particular embodiment includes a particular feature, element, and / or step, while other embodiments do not include the particular feature, element, and / or step. Thus, such conditional language generally is not intended to imply that the feature, element, and / or step is in any way required for one or more embodiments, or that one or more embodiments must include logic for deciding, with or without user input or prompting, whether the feature, element, and / or step is included in any particular embodiment or will be performed in any particular embodiment. Specifically, the terms "comprises" and "comprising" should be interpreted as referring to elements, components, or steps in a non-exclusive manner, which indicates that the recited elements, components, or steps may be present or utilized without explicitly recited other elements, components, or steps, or in combination with such other elements, components, or steps.

[0082] It should be recognized that the embodiments disclosed herein are not mutually exclusive and may be combined with one another in various arrangements. Additionally, although the disclosed methods and devices are described largely in the context of auditory prostheses, the various embodiments described herein may be incorporated into a variety of other suitable devices, methods, and contexts. More specifically, as may be recognized, certain embodiments described herein may be used in the context of various implantable medical devices that may benefit from having two devices in or on a recipient's body, each device having one or more transducers that measure the same aspect of the surrounding environment or the recipient's body.

[0083] As used herein, degree language such as the terms "about," "approximately," "substantially," and "essentially" refer to a value, quantity, or property that is close to the stated value, quantity, or property and still performs the desired function or achieves the desired result. For example, the terms "about," "approximately," "substantially," and "essentially" can refer to a quantity within ±10% of the stated quantity, within ±5% of the stated quantity, within ±2% of the stated quantity, within ±1% of the stated quantity, or within ±0.1% of the stated quantity. As another example, the terms "substantially parallel" and "essentially parallel" refer to a value, quantity, or feature that deviates from exact parallelism by ±10 degrees, ±5 degrees, ±2 degrees, ±1 degree, or ±0.1 degree, and the terms "substantially perpendicular" and "essentially perpendicular" refer to a value, quantity, or feature that deviates from exact perpendicularity by ±10 degrees, ±5 degrees, ±2 degrees, ±1 degree, or ±0.1 degree. The ranges disclosed herein also cover any and all overlapping, sub-ranges, and combinations thereof. Language such as "up to," "at least," "greater than," "less than," "between," etc. includes the recited numbers. As used herein, unless the context clearly dictates otherwise, the meaning of "a / an" and "the" includes the plural. Additionally, as used in the descriptions herein, unless the context clearly dictates otherwise, the meaning of "in" includes "into" and "on."

[0084] Although methods and systems are discussed herein in terms of elements labeled with ordinal adjectives (e.g., first, second, etc.), the ordinal adjectives are merely used as labels to distinguish one element from another (e.g., one signal from another signal, or one circuit from another circuit), and the ordinal adjectives are not used to denote the order of these elements or their order of use.

[0085] The inventions described and claimed herein are not limited in scope by the specific example embodiments disclosed herein, because these embodiments are intended as illustrations of several aspects of the invention and not limitations. Any equivalent embodiments are intended to be within the scope of the invention. Indeed, various modifications in form and detail of the invention will become apparent to those skilled in the art in light of the foregoing description, in addition to those shown and described herein. Such modifications are also intended to fall within the scope of the claims. The breadth and scope of the invention should not be limited by any of the example embodiments disclosed herein, but should be defined only in accordance with the claims and their equivalents.

Claims

1. A device, comprising: at least one first microphone configured to be worn on or within a recipient's body, the at least one first microphone configured to generate a microphone signal indicative of ambient sound from the recipient's environment; a first circuitry configured to receive the microphone signal and, in response to the microphone signal, generate a stimulation signal configured to be received by the recipient's body to evoke the recipient's hearing perception, the stimulation signal indicative of the ambient sound; and a second circuitry configured to: generate first data indicative of a first comparison of a response of the at least one first microphone to the ambient sound at a first time with a response of at least one second microphone to the ambient sound at the first time; generate second data indicative of a second comparison of a response of the at least one first microphone to the ambient sound at a second time, after the first time, with a response of the at least one second microphone of the device to the ambient sound at the second time; and generate a performance assessment of at least one aspect of the device in response to a third comparison of the first data with the second data.

2. The device according to claim 1, wherein the at least one first microphone and the first circuitry are components of a first auditory prosthesis operably communicable with a first auditory subsystem of the recipient, and the at least one second microphone is a component of a second auditory prosthesis separate from the first auditory prosthesis and operably communicable with a second auditory subsystem of the recipient.

3. The device according to claim 2, wherein the first auditory prosthesis and / or the second auditory prosthesis comprises a cochlear implant configured to provide the stimulation signal to a corresponding cochlea of the recipient.

4. The device according to claim 2, wherein the first auditory prosthesis and / or the second auditory prosthesis comprises an auditory prosthesis having an acoustic actuator configured to provide the stimulation signal to a corresponding ossicle of the recipient.

5. The device according to claim 2, wherein the first auditory prosthesis and / or the second auditory prosthesis comprises a bone conduction auditory prosthesis configured to provide the stimulation signal to a corresponding temporal bone portion of the recipient.

6. The device according to claim 2, wherein the first auditory prosthesis and / or the second auditory prosthesis comprises a hearing aid configured to provide the stimulation signal to a corresponding tympanic membrane of the recipient.

7. The apparatus according to any one of the preceding claims, wherein the first data indicates a first frequency response difference between the at least one first microphone and the at least one second microphone and / or a first sensitivity difference between the at least one first microphone and the at least one second microphone, and the second data indicates a second frequency response difference between the at least one first microphone and the at least one second microphone and / or a second sensitivity difference between the at least one first microphone and the at least one second microphone.

8. The apparatus according to any one of the preceding claims, wherein the third comparison comprises comparing a difference between the first data and the second data with a predetermined threshold.

9. The apparatus according to any one of the preceding claims, wherein the second circuitry is configured to evaluate whether the ambient sound at the second time is suitable for generating the second data.

10. The apparatus according to any one of the preceding claims, wherein the second circuitry is configured to generate the second data in response to: a predetermined time interval having elapsed after generating the first data, the ambient sound at the second time having a predetermined property, and / or the second circuitry receiving a sensor signal indicating a condition that may damage the at least one first microphone.

11. The apparatus according to any one of the preceding claims, wherein the second circuitry is configured to generate the first data by receiving a first portion of the microphone signal at the first time and receiving information indicating a first response of the at least one second microphone at the first time, and the first comparison comprises comparing the first portion of the microphone signal at the first time with the information indicating the first response of the at least one second microphone at the first time.

12. The apparatus according to claim 11, wherein the second circuitry is configured to generate the second data by receiving a second portion of the microphone signal at the second time and receiving information indicating a second response of the at least one second microphone at the second time, and the second comparison comprises comparing the second portion of the microphone signal at the second time with the information indicating the second response of the at least one second microphone at the second time.

13. The apparatus according to any one of the preceding claims, wherein the performance evaluation comprises an evaluation of the performance of the at least one first microphone.

14. An apparatus comprising: a communication circuitry configured to receive first information from at least one first transducer and second information from at least one second transducer, the first information and the second information indicating signals from the environment of a recipient or from the body of the recipient; and an evaluation circuitry configured to, during a first time period: receive a first portion of the first information, the first portion of the first information indicating a response of the at least one first transducer to the signal during the first time period; Receive a first portion of the second information, the first portion of the second information indicating the response of the at least one second transducer to the signal during the first time period; And Generate a first comparison of the first portion of the first information and the first portion of the second information; The evaluation circuitry is further configured to, during a second time period after the first time period: Receive a second portion of the first information, the second portion of the first information indicating the response of the at least one first transducer to the signal during the second time period; Receive a second portion of the second information, the second portion of the second information indicating the response of the at least one second transducer to the signal during the second time period; Generate a second comparison of the second portion of the first information and the second portion of the second information; and The evaluation circuitry is further configured to generate a third comparison of the first comparison and the second comparison.

15. The apparatus according to claim 14, wherein the evaluation circuitry is further configured to evaluate the performance of at least one of the at least one first transducer and the at least one second transducer in response to the third comparison.

16. The apparatus according to claim 14 or claim 15, further comprising a smartphone, a tablet computer, or a computer including the communication circuitry and the evaluation circuitry.

17. The apparatus according to any one of claims 14 to 16, wherein both the at least one first transducer and the at least one second transducer are in operative communication with the same sensory prosthesis.

18. The apparatus according to any one of claims 14 to 16, wherein the at least one first transducer is a component of a first sensory prosthesis, and the at least one second transducer is a component of a second sensory prosthesis different from the first sensory prosthesis.

19. The apparatus according to any one of claims 14 to 18, further comprising a stimulation circuitry configured to generate a stimulation signal in response to the first information and the second information and provide the stimulation signal to the recipient's body, the signal including an environmental sensory excitation from the recipient's environment.

20. The apparatus according to any one of claims 14 to 19, wherein the signal is generated by the recipient's body or indicates a property of the recipient's body.

21. A method, comprising: Measuring and storing a first difference value between responses of a first prosthesis and a second prosthesis to an environmental excitation at a first time; Measuring and storing at least one second difference value between responses of the first prosthesis and the second prosthesis to the environmental excitation at a second time after the first time; And Detecting a performance degradation of one of the first prosthesis and the second prosthesis, the detecting including comparing at least one first difference value with the second difference value.

22. The method according to claim 21, wherein the first prosthesis and the second prosthesis are acoustic prostheses worn on or within opposite ears of a recipient's body.

23. The method according to claim 21, wherein the first prosthesis and the second prosthesis are acoustic prostheses worn on or within the same ear of the recipient's body.

24. The method according to any one of claims 21 to 23, wherein detecting the performance degradation further comprises calculating a difference between the first difference value and the second difference value, and determining whether the calculated difference is greater than a predetermined threshold.

25. The method according to claim 24, further comprising generating a signal indicating that performance degradation is detected if the calculated difference is greater than the predetermined threshold.

26. The method according to claim 24 or 25, further comprising generating a signal indicating that no performance degradation is detected if the calculated difference is not greater than the predetermined threshold.

27. A non - transitory computer - readable medium having a computer program stored thereon, the computer program instructing a computer system to perform the method according to any one of claims 21 to 26.

28. An apparatus, comprising: a first device, the first device including at least one first transducer configured to respond to a signal; a second device, the second device including at least one second transducer configured to respond to the signal, at least one of the first device and the second device being configured to be worn on or implanted in the recipient's body; a first circuit system configured to generate first data indicative of a first comparison of the response of the at least one first transducer to the signal at a first time with the response of the at least one second transducer to the signal at the first time; a second circuit system configured to generate second data indicative of a second comparison of the response of the at least one first transducer to the signal at a second time with the response of the at least one second transducer to the signal at the second time, the second time being after the first time; a third circuit system configured to generate a performance assessment of at least one aspect of the apparatus in response to a third comparison of the first data and the second data.

29. The apparatus according to claim 28, wherein the signal comprises a sensory stimulus received from the recipient's surrounding environment.

30. The apparatus according to claim 28, wherein the signal is generated by the recipient's body or indicates a property of the recipient's body.

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