The present invention relates generally to assessment of intraoperative vibrational feedback at an implantable sound input module.
Medical devices have provided a wide range of therapeutic benefits to recipients over recent decades. Medical devices can include internal or implantable components/devices, external or wearable components/devices, or combinations thereof (e.g., a device having an external component communicating with an implantable component). 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 in performing lifesaving and/or lifestyle enhancement functions and/or recipient monitoring for a number of years.
The types of medical devices and the ranges of functions performed thereby have increased over the years. For example, many medical devices, sometimes referred to as “implantable medical devices,” now often include one or more instruments, apparatus, sensors, processors, controllers or other functional mechanical or electrical components that are permanently or temporarily implanted in a recipient. These functional devices are typically used to diagnose, prevent, monitor, treat, or manage a disease/injury or symptom thereof, or to investigate, replace or modify the anatomy or a physiological process. Many of these functional devices utilize power and/or data received from external devices that are part of, or operate in conjunction with, implantable components.
In one aspect, a method is provided. The method comprises: delivering one or more sets of mechanical stimulation signals to a recipient via an actuator of an implantable auditory prosthesis; capturing, at a vibration sensor positioned at a first location in the recipient, vibrations induced by each of the one or more sets of the mechanical stimulation signals; determining a vibrational transfer function between the actuator and the vibration sensor at the first location; and providing a user with an indication of the vibrational transfer function between the actuator and the vibration sensor at the first location.
In another aspect, a method is provided. The method comprises: positioning a sound input module comprising a sound sensor and a vibration sensor at a first location in a recipient; driving an actuator implanted in the recipient with one or more sets of actuator control signals, where each of the one or more sets of actuator control signals cause the actuator to deliver one or more mechanical stimulation signals to the recipient; capturing, at the vibration sensor, vibrations induced by each of the one or more sets of the mechanical stimulation signals; and analyzing attributes of the one or more sets of one or more sets of control signals relative to attributes of the vibrations induced by each of the one or more sets of the mechanical stimulation signals to evaluate a suitability of the first location for implantation of the sound input module at the first location.
In another aspect, one or more non-transitory computer readable storage media are provided. The non-transitory computer readable storage media comprise instructions that, when executed by a processor, cause the processor to: generate one or more sets of actuator control signals at an implantable auditory prosthesis, wherein the implantable auditory prosthesis comprises an actuator and an sound input module each configured to be implanted in a recipient, wherein the sound input module comprises a sound sensor and a vibration sensor; provide the one or more sets of actuator control signals to the actuator to deliver, with the actuator, one or more sets of mechanical stimulation signals to the recipient, wherein each of the one or more sets of mechanical stimulation signals are generated based on at least one of the one or more sets of the actuator control signals; receive, from the vibration sensor, one or more sets of output signals indicating vibrations detected at the vibration sensor in response to each of the one or more sets of mechanical stimulation signals; and generate, based on the one or more sets of actuator control signals and the one or more sets of output signals indicating accelerations detected at the acceleration sensor, an indication of a relative vibration isolation between the acceleration sensor and the actuator.
In another aspect, a system is provided. The system comprises: an actuator configured to be implanted in a recipient and to generate one or more sets of mechanical stimulation signals for delivery to a recipient; a vibration sensor configured to be implanted at a first location in the recipient and configured to capture vibrations induced by each of the one or more sets of the mechanical stimulation signals; and one or more processors configured to: generate, based at least on the vibrations induced by each of the one or more sets of the mechanical stimulation signals, a vibrational transfer function between the actuator and the vibration sensor at the first location.
Embodiments of the present invention are described herein in conjunction with the accompanying drawings, in which:
Presented herein are techniques for generating information characterizing an amount of vibration isolation between an implantable vibration sensor and an implantable mechanical actuator (actuator), when each are implanted in a recipient. In particular, the implantable mechanical actuator is configured to generate and deliver, based on one or more actuator control signals, mechanical stimulation signals to the recipient. The vibration sensor is configured to capture vibrations induced by the delivery of the mechanical stimulation signals to the recipient. A vibrational transfer function relating a position of the vibration sensor to the actuator is then generated based on the captured vibrations and the attributes of the actuator control signals. The vibrational transfer function provides an indication of the vibration isolation present between the vibration sensor and the actuator, at their respective locations within the recipient.
Merely for ease of description, the techniques presented herein are primarily described herein with reference to a totally implantable middle ear auditory prostheses (middle ear implant). However, it is to be appreciated that the techniques presented herein may also be incorporated into, or performed by, a variety of other implantable medical devices. For example, the techniques presented herein may be used with other auditory prostheses, including cochlear implants, bone conduction devices, direct acoustic stimulators, auditory brain stimulators, etc. The techniques presented herein may also be used with vestibular devices (e.g., vestibular implants), visual devices (i.e., bionic eyes), sensors, pacemakers, drug delivery systems, defibrillators, functional electrical stimulation devices, catheters, seizure devices (e.g., devices for monitoring and/or treating epileptic events), sleep apnea devices, electroporation devices, etc.
The middle ear auditory prosthesis 100 of
In general, the vibration sensor 114 is mechanically attached to the housing 110 such that body noises (vibrations) passed to the housing can be detected/captured by the vibration sensor (e.g., sense vibrations of the housing). The housing 110 is hermetically sealed and includes a diaphragm 116 that is proximate to the sound sensor 112. The diaphragm 116 may be unitary with the housing 116 and/or may be a separate element that is attached (e.g., welded) to the housing 112. The sound input unit 102 is configured to be implanted within the recipient 101. In one example shown in
The implantable sound sensor 112 and the vibration sensor 114 may each be electrically connected to the implant body 104. In operation, the sound sensor 112 and the vibration sensor 114 detect input signals (e.g., external acoustic sounds and/or vibrations) and convert the detected input signals into electrical signals that are provided to the processing unit 118 (e.g., via lead 120). In
In the example of
Memory 124 may comprise any suitable volatile or non-volatile computer readable storage media including, for example, random access memory (RAM), cache memory, persistent storage (e.g., semiconductor storage device, read-only memory (ROM), erasable programmable read-only memory (EPROM), flash memory, etc.), or any other computer readable storage media that is capable of storing program instructions or digital information. The processing unit 118 may be implemented, for example, on one or more printed circuit boards (PCBs).
It is to be appreciated that the arrangement for processing unit 118 in
As shown, the implant body 114 includes a hermetically sealed housing 128 in which the processing unit 118 is disposed. Also disposed in the housing 128 is a power source (e.g., rechargeable battery) 130 and a radio-frequency (RF) interface circuitry 132. Electrically connected to the RF interface circuitry 132 is the implantable coil 108, which is disposed outside of the housing 128.. In general, the implantable coil 108 and the RF interface circuitry 132 enable the receipt of power and data from an external device (not shown in
As noted, the RF interface circuitry 132 and the implantable coil 108 enable the middle ear auditory prosthesis 100 to receive data/power from and/or transfer data to, an external device. That is, modulated signals transmitted bi-directionally through the inductive link (RF coil 108 and an external ) are used to support battery charging, device programming, status queries and user remote control.
In certain examples, the external device may comprise an off-the-ear (OTE) unit. In other examples, the external device may comprise a behind-the-ear ear (BTE) unit or a micro-BTE unit, configured to be worn adjacent to the recipient’s outer ear. Alternative external devices could comprise a device worn in the recipient’s ear canal, a body-worn processor, a fitting system, a computing device, a consumer electronic device (e.g., mobile phone communication), etc. For example, as described further below, during surgery, the middle ear prosthesis 100 is configured to be in communication with a computing device to display an indication of a location-dependent transfer function to a user (e.g., surgeon).
As noted above, the processing unit 118 generates stimulation control signals 121. The stimulation control signals 121 are provided to the actuator 106 (e.g., via lead 134) for use in delivering mechanical stimulation signals to the recipient. In
In the example of
As shown in
In operation, the actuator 106 is configured to generate vibration 123 based on the stimulation control signals 121 received from the processing unit 118. Since, as noted, the ossicles 136 are coupled to the oval window (not shown) of cochlea 138, vibration imparted to the ossicles 136 by the actuator 106 will, in turn, cause oval window to articulate (vibrate) in response thereto. Similar to the case with normal hearing, this vibration of the oval window sets up waves of fluid motion of the perilymph within cochlea 138 which, in turn, activates the hair cells inside of the cochlea 138. Activation of the hair cells causes appropriate nerve impulses to be generated and transferred through the spiral ganglion cells (not shown) and auditory nerve (not shown) to the brain (also not shown), where they are perceived as sounds.
It is to be appreciated that the arrangement shown in
The middle ear auditory prosthesis 100 of
With a fully implantable middle ear auditory prosthesis, such as prosthesis 100, there is a potential vibrational feedback pathway where vibration is transmitted from the implanted actuator 106 to the implantable sensors 144. This vibrational feedback (i.e., a portion of the vibration delivered to the recipient) may limit a gain available for use in delivering the mechanical stimulation signals (vibration) to the recipient. In particular, the vibrational feedback could interfere with operation of the sound sensor 112 and, potentially, limit the gain that could be used to generate the mechanical stimulation signals. However, the vibrational feedback can be significantly reduced or substantially eliminated through appropriate placement of the implantable sensors 144 relative to the actuator 106. In particular, the sound sensor 112 should be implanted at a location such that the vibrational feedback captured/received by the sound sensor 112 is below a threshold level.
More specifically, as noted above, the actuator 106 is configured to deliver mechanical stimulation signals (vibration) 123 to the recipient. Although the actuator 106 is configured to deliver the mechanical stimulation signals 123 to the recipient via the ossicles, cochlea, etc., the mechanical stimulation signals may also be partially imparted to other internal structures, such as the recipient’s skull bone, via the fixation system 142 (which itself is mechanical secured to the skull bone). Depending on the implanted location of the sound sensor 112, there may be a physical pathway (e.g., formed by bones, cartilage, implanted components, or other internal structures) that enables a portion of the mechanical stimulation signals generated by the actuator 106, and imparted to the recipient’s skull bone or other internal structure(s), to reach the housing 110 of the sound input unit 102 and, in turn, reach the sound sensor 112 within the housing 110. This portion of the mechanical stimulation signals that passes to the sound sensor 112 is sometimes referred to herein as “vibrational feedback.”. The physical pathway that enables the vibrational feedback to reach the sound sensor 112 is sometimes to herein as a “vibrational feedback path.”
A particularly problematic situation occurs when, following implantation, there is physical contact between the housing 110 of the sound input unit 102 and actuator arrangement 145, which creates what is referred to herein as a “direct” vibrational feedback path between the sound sensor 112 and the actuator 106. If such a direct vibrational feedback path is present, when the actuator 106 delivers mechanical stimulation signals to the recipient, a portion of those mechanical stimulation signals are channeled directly to the housing 110 and the sound sensor 112.
A recipient’s specific anatomical structure/situation, surgical access, etc. may limit what a surgeon is able to see during the surgical implantation. As such, avoiding direct contact between the housing 110 and the actuator arrangement 145 (i.e., actuator 106 and/or the actuator fixation system 142) may not be as a simple as performing an in-situ visual inspection during the surgery. For example, a surgeon could perform the surgery and believe, with his/her limited visibility, that there is a physical separation between the housing 110 of sound input unit 102 and actuator arrangement 145 when in fact the housing 110 and actuator arrangement 145 are still in direct contact with one another.
Moreover, each recipient has different physical characteristics (e.g., bone density at certain locations) that could affect the amount of vibrational feedback that reaches the sound sensor 112 at different locations in the recipient. That is, the sound sensor 112 may, at certain locations, due to the physical characteristics of the specific recipient, be less vibrationally sensitive to the mechanical stimulation signals generated by the actuator 106 than at other locations. Therefore, the sound sensor 112 may be affected by the vibrational feedback differently at different implanted locations.
As noted above, vibrational feedback that reaches the sound sensor 112, as a result of operation of the implanted actuator 106, may limit the gain available for use in delivering the mechanical stimulation signals to the recipient. Also as noted above, the vibrational feedback that reaches the sound sensor 112, as a result of operation of the implanted actuator 106, is a function of the vibrational feedback path and the attributes of the mechanical stimulation delivered to the recipient. As such, it would be ideal to intra-operatively determine (i.e., during surgical implantation of the prosthesis 100) how the sound sensor 112 will be affected by vibrational feedback from the actuator 106 at a given implanted location with the recipient. That is, it would be beneficial to determine the vibrational response of the sound sensor 112 to vibration of the actuator 106, before the suture is closed during surgery.
However, it has been discovered that it is not possible to intraoperatively determine the vibrational response of an implanted sound sensor to the vibration of an implanted actuator because the intraoperative vibration sensitivity of a sound is very different from the post-operative vibration sensitivity of the sound sensor. The difference in intraoperative vibration sensitivity and post-operative vibration sensitivity of a sound sensor is a result of a number of post-surgical factors, such as skin flap thickness (i.e., the thickness of the layer of skin that will positioned over the sound sensor), skin tension, healing processes, etc., none of which can be accurately accounted for in the surgical environment.
As such, recognizing the differences in intraoperative vibration sensitivity and post-operative vibration sensitivity of a sound sensor, the inventors of the present application have proposed techniques to intraoperatively generate/determine an estimated vibrational sensitivity of a sound sensor to the actuator based on data captured by a vibration sensor that is co-located with the sound sensor (e.g., the sound sensor and vibration sensor are both located within a sound input module). Stated differently, presented herein are techniques that intraoperatively determine (i.e., during surgical implantation of the prosthesis) how a vibration sensor will be affected by vibrational feedback from the actuator at a given implanted location with the recipient. However, such determinations are made based on data obtained from a vibration sensor, and not based on data obtained by the sound sensor. In particular, the vibration sensor, which is co-located with the sound sensor, and which is rigidly coupled to the skull, has a vibration sensitivity that is independent of the post-surgical factors that affect/change the sensitivity of the sound sensor (i.e., the sensitivity of the vibration sensor is independent of skin flap thickness, skin tension, healing processes, etc.). As such, the data captured from the vibration sensor is used to objectively evaluate a suitability of a location for implantation of the sound input module.
Accordingly, presented herein are in-situ techniques that capture/acquire data that objectively characterize the implanted location of an implantable sound sensor relative to an implanted location of an implantable actuator arrangement, but do so based on indirect/tangential data related to the co-located vibration sensor. In particular, in accordance with the techniques presented herein, the processing unit of the auditory prosthesis (e.g., middle ear auditory prosthesis 100) is used, in-situ, to capture data, sometimes referred to herein as “vibrational feedback data,” representing the vibrational transfer function between the vibration sensor 114 and the actuator 106. In general, the vibrational feedback data includes the vibrations detected by the vibration sensor 114 and/or attributes of the actuator control signals that induced those vibrations. The vibrational transfer function, which is generated from the vibrational feedback data, represents the vibrations detected by the vibration sensor 114, relative to attributes of the actuator control signals that induced those vibrations (i.e., data representing the electrical output provided to the implanted actuator relative to the electrical output from the implanted vibration sensor).
In the example of
As described further below, the vibrational transfer function can be provided to a user (e.g., surgeon). If the vibrational transfer function has values outside of an acceptable range, then that is an indicator of misplacement of the entire sound input unit 102, and therefore misplacement of the sound sensor 112, relative to the actuator arrangement 145. Accordingly, the techniques presented herein provide the ability to perform an objective assessment of the placement of the vibration sensor with regard to its impact on gain, which provides guidance to surgeons, especially less experienced surgeons.
As noted, the vibrational transfer function from the input to the implanted actuator (e.g., stimulation control signals 121) to the output from the vibration sensor (e.g., vibration sensor output signals 119) is measured intraoperatively. However, this measurement may be performed in several different manners, including via an open-loop measurement technique or via a closed-loop measurement technique. Further details regarding example open-loop measurement techniques are provided below with reference to
Referring first to
In general, the feedback that reaches vibration sensor 114 is dependent on the frequency of the test signals 223. That is, the vibrational transfer function will vary with frequency. As such, the test signals 223 (and thus the test control signals 250) will include a plurality of different frequencies (e.g., different frequencies in the range of 250 Hertz (Hz) to 4,000 Hz) so as enable objective evaluation of the feedback across a selected frequency range.
In certain embodiments, the test control signals 250 are generated by the processing unit 118. However, in other embodiments, the test control signals 250 are calculated by an external device (e.g., external device 260 shown in
Returning to the specific example of
The vibrational feedback 254 that passes through the vibrational feedback path 252 is captured/detected by the vibration sensor 114 as vibrations, which in turn results in the generation of corresponding vibration sensor output signals 219.
The vibration sensor 114 provides the vibration sensor output signals 219 to the processing unit 118. In certain embodiments, the processing unit 118 is configured to analyze the one or more vibration sensor output signals 219 relative to the test signals 250 to determine the vibrational transfer function for the vibration sensor 114 at the specific implanted location. That is, the processing unit 118 is configured to determine, based on the vibration sensor output signals 219 and the test signals 250, how the vibration sensor 114 is affected by vibration of the actuator 106, when the vibration sensor 114 is at the specific implanted location. As such, the transfer function for the vibration sensor 114 is location-dependent and is sometimes referred to herein as a “location-dependent vibrational transfer function.”
The processing unit 118 receives input signal seen by the vibration sensor 114 (represented in the vibration sensor output signals 219), where this input signal is a combination of the vibrational feedback 254 (signal of interest) and uncorrelated background noise, which is irrelevant, but may be larger than the signal of interest and may therefore prevent the determination of the value of the signal of interest. Methods to increase the level of the relevant (feedback) signal relative to the level of the irrelevant (background noise) signal, such as time-domain averaging or filtering, can be employed to generate a “clean” input signal used to determine the vibrational transfer function. The vibrational transfer function is the ratio of the input signal level seen by the vibration sensor 114 (represented in the vibration sensor output signals 219) to the output signal level produced by the actuator 106, on a per frequency basis. These levels can be expressed as peak or as RMS values.
As noted, the vibrations captured by the vibration sensor 114 are in-situ measurements. As such, in certain examples, the processing unit 118 is configured to perform some pre-processing of the vibration sensor output signals 219. For example, the vibration sensor output signals 219 may be pre-processed to normalize for background noises (e.g., the recipient’s breathing, etc.), the vibration sensor output signals 219 may be filtered for extraction of the actuator signals (e.g., for the frequency of the sinewave used to drive into the actuator), etc. and to isolate the vibrations attributable to the mechanical stimulation signals.
Returning to
The location-dependent vibrational transfer function can be used to obj ectively evaluate the implanted location of the sound input module 102, which includes both the sound sensor 112 and the vibration sensor 114. For example, if the location-dependent vibrational transfer function is outside of an acceptable range (e.g., above a certain threshold) at one or more frequencies, then that is an indicator of misplacement of the sound input module 102 relative to the actuator arrangement 145. If the location-dependent vibrational transfer function is outside of the acceptable range, the surgeon may change the location of the sound input module 102 relative to the actuator arrangement 145 (e.g., re-locate one or more of the sound input module 102 and or the fixation system 142).
Once the location of the sound input module 102 relative to the actuator arrangement 145 is changed, an updated location-dependent vibrational transfer function can be determined (e.g., in substantially the same was as was described above). The updated location-dependent vibrational transfer function can again be used to objectively evaluate the implanted location of the sound input module 102. This process can be continued until an acceptable location-dependent vibrational transfer function is determined. At that point, the measurements can be terminated and the surgeon can complete the remainder of the surgery (e.g., close the surgical incision, etc.).
As noted,
For example, in an alternative embodiment, the processing unit 118 obtains the vibration sensor output signals 219 and then streams, in real-time, the vibration sensor output signals 219 to the external device 260. In these examples, the external device 260 also is aware of the attributes of test signals 250 (e.g., determines the one or more test signals, receives the attributes of the one or more test signals from the processing unit 118, etc.) and, as such, can determine the location-dependent vibrational transfer function.
As noted,
More specifically, in the example of
When the initial signals 350 are used to drive the actuator 106, a portion of the initial vibration 323 may pass from the actuator 106 and/or the fixation system 142 to the vibration sensor 114 via a vibrational feedback path. The portion of the initial vibration 323 that passes from the actuator 106 and/or the fixation system 142 to the vibration sensor 114 is referred to herein as “initial” vibrational feedback. As noted above, the vibrational feedback path may be a direct path (i.e., where the feedback passes directly from the actuator arrangement 145 to the housing 110 coupled to the vibration sensor 114) or an indirect path (e.g., where the feedback passes from the actuator arrangement 145 the housing 110 coupled to the vibration sensor 114 via bones, cartilage, etc.). In
The initial vibrational feedback 354 that passes through the vibrational feedback path 352 is captured/detected by the vibration sensor 114 as vibrations, which in turn results in the generation of corresponding vibration sensor output signals 319. This output signals 319 are then provided to the processing unit 118 for amplification and stimulation of the recipient.
Therefore, a process of: (1) delivering amplified test control signals to the actuator 106 (represented by arrows 355(A)-355(N)), (2) delivering amplified test signals to the recipient via the actuator (represented by arrows 357(A)-357(N)), (3) capturing amplified vibrational feedback at the vibration sensor 114, and (4) and providing corresponding vibration sensor output signals to the processing unit 118 (represented by arrows 361(A)-361(N)) is iteratively repeated, where the applied gain (and thus vibrational feedback) increases with each iteration. The iterations continue until the applied gain causes the processing unit 118 to detect a maximum stable gain (e.g., how much gain can be provided without getting feedback). In certain examples, maximum stable gain has been surpassed when “squealing” is detected. In general, squealing is the point at which the system detects that the output level saturates, i.e. reaches the maximum permitted by the amplifier input-output curve. That is, once the applied gain reaches a certain level, then the amount of vibrational feedback detected by the vibration sensor 114 will become too high, which can be detected in the processing unit 118. In this way, the processing 118 is configured to determine the gain level that will result in the squealing, which indicates that the maximum stable gain for the system has been exceeded. The location-dependent vibrational transfer function for the vibration sensor (i.e., how the vibration sensor 114 is affected by vibration of the actuator 106, when the vibration sensor 114 is at the specific implanted location) can, in turn, be deduced from the maximum stable gain.
For example, the system can perform a measurement of the feedback path, referred to as the “device under test” (DUT). The input to the DUT is the voltage out of the implant to the actuator. The output of the DUT is the voltage out of the vibration sensor. As such, a vibrational transfer function of 0.1 means that, if the actuator is driven with 500 mV, then the system will measure 50 mV at the vibration sensor. Assume now that a sound creates an actuator input of 1 mV and the processing unit amplifies the input by a factor of nine (9), the 1 mV signal will get amplified to 1 ×9 or 9 mV at the output, which will result in a feedback signal of 0.9 mV in the next “cycle”, and 0.9 × 9 × 0.1 in the next cycle, and less, and less, then the system is stable. However, if the processor amplifies by a factor of eleven (11), then a 1 mV input signal will become 11 mV at the output, which will cause a feedback signal of 1.1 mV in the next cycle, and 1.1 × 11 × 0.1 in the next cycle, and more, and more, until the system saturates, which creates audible feedback. Therefore, if the feedback gain is G, then the maximum stable forward gain that will not create this catastrophic behavior if it is just under 1/G.
As noted, the feedback that reaches vibration sensor 114 is dependent on the frequency of the signals. That is, the vibrational transfer function will vary with frequency. As such, the closed-loop measurement, described above, may be performed at a plurality of different frequencies (e.g., different frequencies in the range of 250 Hertz (Hz) to 4,000 Hz) so as enable objective evaluation of the feedback across a selected frequency range.
Similar to the above embodiments, data representing the location-dependent vibrational transfer function may be sent to an external device for further analysis and/or for presentation to the surgeon. As described further below, the location-dependent vibrational transfer function can be presented to a user (e.g., surgeon) in a number of different manners, such as via visual displays, audible tones, etc. In
As in the above embodiments, the location-dependent vibrational transfer function can be used to objectively evaluate the implanted location of the sound input module 102 (which includes the sound sensor 112 and the vibration sensor 114). For example, if the location-dependent vibrational transfer function is outside of an acceptable range (e.g., above a certain threshold) at one or more frequencies, then that is an indicator of misplacement of the sound input module 102 relative to the actuator arrangement 145. If the location-dependent vibrational transfer function is outside of the acceptable range, the surgeon may change the location of the sound input module 102 relative to the actuator arrangement 145 (e.g., re-locate one or more of the sound input module 102 and/or the fixation system 142).
Once the location of the sound input module 102 relative to the actuator arrangement 145 is changed, an updated location-dependent vibrational transfer function can be determined (e.g., in substantially the same was as was described above). The updated location-dependent vibrational transfer function can again be used to objectively evaluate the implanted location of the sound input module 102. This process can be continued until an acceptable location-dependent vibrational transfer function is determined. At that point, the measurements can be terminated and the surgeon can complete the remainder of the surgery (e.g., close the surgical incision, etc.).
As noted,
As noted, a location-dependent vibrational transfer function for vibration sensor 114, determined as described herein provides, an objective indication of the vibrational sensitivity of the sound sensor 112 (which is co-located with the vibration sensor in the sound input module 102) to vibration of the actuator 106, at their respective locations within the recipient. Also as noted, direct contact between the actuator arrangement 145 and the housing 110 of the sound input module 102 is positioned problematic. In addition, also as noted above, due to recipient-specific physical characteristics, different positions with each recipient will provide greater or less amounts of vibration sensitivity. 106. As such, in practice, the techniques presented herein may be implemented in several different manners.
For example, in certain embodiments, the actuator 106 may be implanted in the recipient at a target location, and the vibration sensor 114 is implanted at a first location. This first location could be selected based, for example, on normative data (e.g., studies, prior recipient data, etc.). One of the above techniques is the used to determine the location-dependent vibrational transfer function for the vibration sensor 114 at that first location. The location-dependent vibrational transfer function determined for the vibration sensor 114 at that first location could then be compared to a predetermined location-dependent vibrational transfer function to evaluate whether the first location is acceptable (e.g., if the vibrational feedback between the vibration sensor 114 and the actuator 106 is less than a predetermined threshold at the first location). If not, the vibration sensor 114 can be moved to a second location where the process is repeated to determine a location-dependent feedback transfer for the vibration sensor 114 at the second location. This process can be repeated for several locations and the results for each location compared to one another in order to select a preferred/optimal location. Alternatively, the process can be repeated until a location having an acceptable location-dependent vibrational transfer function is identified.
As noted above, the location-dependent vibrational transfer function may be provided to a user (e.g., surgeon) in a number of different manners. In certain embodiments, the results of the location-dependent vibrational transfer function can be analyzed relative to normative data (e.g., derived from previous surgeries, cadaver studies, etc.) and the user is provided with an indication of whether the evaluated location is acceptable. For example, the result of the comparison could be displayed as a pass/fail categorization for the specific (tested) vibration sensor location (e.g., by expressing present results in relation to the distribution of normative values, e.g. as a percentile, etc.). The pass/fail indication would a visible indication, audible indication, etc.
In certain embodiments, the location-dependent vibrational transfer function is presented to the user in a numerical form by an external device (e.g., external devices 260 or 260) in communication with the processing unit 118. In other embodiments, the results of a transfer function measurement are presented to the clinician in graphical form, such as a curve of feedback gain versus frequency, by an external device.
For example, shown in
In
In one example of
In one example, the graph 466 could be displayed to a user. However, in another example, the data represented in graph 466 could be displayed to a user in one or more other formats. For example,
In other embodiments, the results of a transfer function measurement could be presented to the user as an acoustic signal, where the relevant value is encoded in at least one of loudness, pitch, and/or repetition rate of the acoustic signal. For example, low frequency beeps could indicate a low transfer function (i.e., low feedback), while high frequency beeps could indicate a high transfer function (i.e., high feedback), etc.
As noted above, the techniques presented herein enable the objective evaluation/assessment of the placement of an implantable sound input module, relative to an implantable actuator, by determining a vibrational transfer function between an implantable vibration sensor (co-located with a sound sensor in the sound input module) and the implantable actuator. In certain embodiments, the suitability of an implanted location for a sound input module is determined by comparing two or more location-dependent vibrational transfer functions, each associated with different locations, to one another. The location with the lowest location-dependent vibrational transfer function (i.e., indicating the lowest feedback between the vibration sensor and the actuator) is selected as an optimal or preferred location.
In certain embodiments, the suitability of an implanted location for a sound input module is determined by comparing a location-dependent vibrational transfer function determined for the implanted location to one or more predetermined vibrational transfer functions. That is, if the location-dependent vibrational transfer function indicates that the vibrational feedback is below a predetermined threshold levels for selected frequencies, then the location corresponding to that location-dependent vibrational transfer function may be a suitable location for the sound input module. In certain such embodiments, the predetermined vibrational transfer function may be a standard predetermined vibrational transfer function for all patients. However, in other embodiments, the predetermined vibrational feedback transfer used for comparison can be different for different recipients.
For example, recipient’s may have different levels of hearing loss which, in turn, affects the amount of gain that needs to be applied by the implantable middle ear auditory prosthesis. As noted, the amount of vibrational feedback can limit the amount of gain that can be applied. Therefore, with recipient’s having greater hearing loss (and thus requiring greater gain), there is a need to ensure that the sound sensor is less sensitive to vibration of the actuator. However, with recipient’s having less hearing loss (and thus requiring less gain), the need for less vibrational sensitivity of the sound sensor to vibration of the actuator may be less important. Accordingly, the predetermined vibrational transfer function used for comparison to a location-dependent vibrational transfer function could be a function of the recipient’s hearing loss, where lower vibrational feedback is required for recipient’s with greater hearing loss.
In one example, the recipient’s audiometric data (e.g., audiogram) could be entered or imported before surgery and the system calculate how much gain the recipient is likely to need (plus some safety margin) to account for, for example, possible inaccuracies of the measurements and calculations and/or foreseeable progression of the recipient’s hearing loss for some period of time in the future. This information could, in turn, be used to calculate the predetermined vibrational transfer function used for comparison to a location-dependent vibrational transfer function. Stated differently, the total required gain (represented by the predetermined vibrational transfer function, as determined from the hearing loss) could be compared to the prediction achievable gain (represented by the location-dependent vibrational transfer function). If the currently achievable gain is far below the required gain, then the user would be provided an indication that the tested location is unacceptable. If the achievable gain is acceptable, either because the achievable gain is very high (low feedback, good surgical result, etc.), or because the required gain is low (mediocre feedback, but good residual hearing of the patient), then the user would be provided an indication that the tested location is acceptable
As noted above, aspects of the techniques presented herein may be performed at an external device, such as external devices 260 and 360 of
Computing 671 comprises one or more interfaces/ports 673(1)-673(N), a memory 676, a processor 678, and a user interface 679. The interfaces 673(1)-673(N) may comprise, for example, any combination of network ports (e.g., Ethernet ports), wireless network interfaces, Universal Serial Bus (USB) ports, Institute of Electrical and Electronics Engineers (IEEE) 1394 interfaces, PS/2 ports, etc. In the example of
The user interface 679 includes one or more output devices, such as a liquid crystal display (LCD) and a speaker, for presentation of visual or audible information to a clinician, audiologist, or other user. The user interface 679 may also comprise one or more input devices that include, for example, a keypad, keyboard, mouse, touchscreen, etc.
The memory 676 comprises signal acquisition logic 677. In general, the signal acquisition logic 677, when executed by the processor 678, causes the computing device 671 to perform operations described elsewhere herein. For example, in certain embodiments, the signal acquisition logic 677 may be executed to provide a user with an audible or visual indication of a vibrational transfer function. In certain embodiments, the vibrational transfer function feedback analysis logic 677 may also be executed to determine the vibrational transfer function and/or control aspects of an open-loop or closed-loop feedback measurement at the middle ear auditory prosthesis 100.
Memory 676 may comprise read only memory (ROM), random access memory (RAM), magnetic disk storage media devices, optical storage media devices, flash memory devices, electrical, optical, or other physical/tangible memory storage devices. The processor 678 is, for example, a microprocessor or microcontroller that executes instructions for the signal acquisition logic 677. Thus, in general, the memory 676 may comprise one or more tangible (non-transitory) computer readable storage media (e.g., a memory device) encoded with software comprising computer executable instructions and when the software is executed (by the processor 678) it is operable to perform the techniques described herein.
It is to be appreciated that the arrangement for computing device 671 shown in
Embodiments have been primarily described above with reference to implantable actuators that delivery vibration to, for example, the recipient’s ossicular chain and/or the recipient’s cochlea. However, as noted elsewhere herein, these embodiments are merely illustrative and the techniques presented herein may be implemented with any of a number of different implantable actuators. For example, the techniques presented herein may be implemented with implantable actuators that delivery vibration directly to the skull bone of the recipient (e.g., active transcutaneous bone conduction devices). In another example, the techniques presented herein may be implemented with implantable actuators that are part of a prosthesis that delivers both mechanical stimulation and another type of stimulation (e.g., electrical stimulation) to the recipient, such as an electro-acoustic hearing prosthesis. More generally, the techniques presented herein are applicable to any implantable medical device having an implantable actuator an a sound input unit/module with co-located vibration and sound sensors.
It is to be appreciated that the embodiments presented herein are not mutually exclusive and that the various embodiments may be combined with another in any of a number of different manners.
The invention described and claimed herein is not to be limited in scope by the specific preferred embodiments herein disclosed, since these embodiments are intended as illustrations, and not limitations, of several aspects of the invention. Any equivalent embodiments are intended to be within the scope of this invention. Indeed, various modifications of the invention in addition to those shown and described herein will become apparent to those skilled in the art from the foregoing description. Such modifications are also intended to fall within the scope of the appended claims.
Filing Document | Filing Date | Country | Kind |
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PCT/IB2021/051300 | 2/16/2021 | WO |
Number | Date | Country | |
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62993918 | Mar 2020 | US |