WO2025230847A1 - Cochlear implant calibration and health indications based on middle ear pressure - Google Patents

Abstract

A system and methodology for utilizing middle ear pressure of a recipient patient is provided. The system includes a pressure sensor configured to be placed in a middle ear of the patient, the pressure sensor providing a pressure signal indicative of pressure in the middle ear. A controller is configured to receive the pressure signal, and determine an output signal based at least on the pressure signal and without requiring an acoustic stimulus. The output signal may be a heart rate, a heart rate variability. a middle ear pressure, a blood pressure, an eustachian tube function, and/or an occurrence of a stapedius reflex response.

Description

Cochlear Implant Calibration and Health Indications Based on Middle Ear Pressure

Cross-Reference to Related Applications

[0001] This application is a continuation of European Patent Application EP24173198. filed April 29, 2024, which is hereby incorporated herein by reference in its entirety.

Technical Field

[0002] The present invention relates to systems and methodologies that sense pressure in the middle ear and determine, based at least on the sensed pressure, and without having to provide an acoustic stimulus or signal, at least one of heart rate, heart rate variability, middle ear pressure, blood pressure, eustachian tube function, and/or an occurrence of a stapedius reflex response. Illustratively, the determination of the stapedius reflex response can advantageously assist in fitting a cochlear implant.

Background Art

[0003] A normal ear transmits sounds as shown in Figure 1 through the outer ear 101 to the tympanic membrane 102, which moves the bones of the middle ear 103 (malleus, incus, and stapes) that vibrate the oval window and round window openings of the cochlea 104. The cochlea 104 is a long narrow duct wound spirally about its axis for approximately two and a half turns. It includes an upper channel known as the scala vestibuli and a lower channel known as the scala tympani, which are connected by the cochlear duct. The cochlea 104 forms an upright spiraling cone with a center called the modiolus where the spiral ganglion cells of the acoustic nerve 113 reside. In response to received sounds transmitted by the middle ear 103, the fluid-filled cochlea 104 functions as a transducer to generate electric pulses which are transmitted to the cochlear nerve 113, and ultimately to the brain.

[0004] Hearing is impaired when there are problems in the ability to transduce external sounds into meaningful action potentials along the neural substrate of the cochlea 104. To improve impaired hearing, hearing prostheses have been developed. For example, when the impairment is related to operation of the middle ear 103, a conventional hearing aid may be used to provide mechanical stimulation to the auditory system in the form of amplified sound. Or when the impairment is associated with the cochlea 104, a cochlear implant with an implanted stimulation electrode can electrically stimulate audit ory nerve tissue with small currents delivered by multiple electrode contacts distributed along the electrode.

[0005] Figure 1 also shows some components of a typical cochlear implant system, including an external microphone that provides an audio signal input to an external signal processor 111 where various signal processing schemes can be implemented. The processed signal is then converted into a digital data format, such as a sequence of data frames, for transmission into the implant 108. Besides receiving the processed audio information, the implant 108 also performs additional signal processing such as error correction, pulse formation, etc., and produces a stimulation pattern (based on the extracted audio information) that is sent through an electrode lead 109 to an implanted electrode array 110.

[0006] Typically, the electrode array 110 includes multiple electrode contacts 112 on its surface that provide selective stimulation of the cochlea 104. Depending on context, the electrode contacts 112 are also referred to as electrode channels. In cochlear implants today, a relatively small number of electrode channels are each associated with relatively broad frequency bands, with each electrode contact 112 addressing a group of neurons with an electric stimulation pulse having a charge that is derived from the instantaneous amplitude of the signal envelope within that frequency band.

[0007] It is well-known in the field that electric stimulation at different locations within the cochlea produce different frequency percepts. The underlying mechanism in normal acoustic hearing is referred to as the tonotopic principle. In cochlear implant users, the tonotopic organization of the cochlea has been extensively investigated; for example, see Vermeire et al., Neural tonotopy in cochlear implants: An evaluation in unilateral cochlear implant patients with unilateral deafness and tinnitus, Hear Res. 245(1-2), 2008 Sep 12 p. 98-106; and Schatzer et al., Electric-acoustic pitch comparisons in single-sided-deaf cochlear implant users: Frequency-place functions and rate pitch. Hear Res, 309, 2014 Mar, p. 26-35 (both of which are incorporated herein by reference in their entireties).

[0008] In some stimulation signal coding strategies, stimulation pulses are applied at a constant rate across all electrode channels, whereas in other coding strategies, stimulation pulses are applied at a channel-specific rate. Various specific signal processing schemes can be implemented to produce the electrical stimulation signals. Signal processing approaches that are well-known in the field of cochlear implants include continuous interleaved sampling (CIS), channel specific sampling sequences (CSSS) (as described in U.S. Patent No. 6,348,070, incorporated herein by reference), spectral peak (SPEAK), and compressed analog (CA) processing.

[0009] For an audio prosthesis such as a cochlear implant to work correctly, some patientspecific operating parameters need to be determined in a fit adjustment procedure where the type and number of operating parameters are device dependent and stimulation strategy’ dependent. Possible patient-specific operating parameters for a cochlear implant include:

THRi (lower threshold of stimulation amplitude) for Electrode 1 MCLi (most comfortable loudness) for Electrode 1 Phase Duration for Electrode 1 THR.2 for Electrode 2 MCL2 for Electrode 2 Phase Duration for Electrode 2

Pulse Rate (may be also channel dependent) Number of fine structure channels Compression Parameters of frequency->electrode mapping Parameters describing the electrical field distribution

[0010] Figure 2 shows a block diagram of a cochlear implant fitting system configured to perform such post-implantation fitting. Control Unit 201 for Recording and Stimulation, for example, a Med-El Maestro Cochlear Implant (CI) system, generates stimulation signals and analyzes response measurements. Connected to the Control Unit 201 is an Interface Box 202, for example, a Diagnostic Interface System such as the DIB 11 conventionally used with the Maestro CI system that formats and distributes the input and output signals between the Control Unit 201 and the system components implanted in the Patient 206. For example, as shown in Figure 2, there may be an Interface Lead 203 connected at one end to the Interface Box 202 and at the other end to an external signal processor 207 of a cochlear implant or other cochlear implant components. After delivering a stimulation pulse, a cochlear implant electrode 205 may be used as a sensing element to determine current and voltage characteristics of the adjacent tissue.

[0011] One common method for fit adjustment is to behaviorally find the threshold (THR) and most comfortable loudness (MCL) value for each separate electrode contact. See for example, Ratz, Fitting Guide for First Fitting with MAESTRO 2.0, MED-EL, Furstenweg 77a, 6020 Innsbruck, 1.0 Edition. 2007. AW 5420 Rev. 1.0 (English EU); incorporated herein by reference. Other altematives/extensions are sometimes used with a reduced set of operating parameters; e.g. as suggested by Smoorenburg, Cochlear Implant Ear Marks, University Medical Centre Utrecht, 2006; and U.S. Patent Application 20060235332; which are incorporated herein by reference. Typically each stimulation channel is fitted separately without using the information from already fitted channels. The stimulation current on a given electrode typically is increased in steps from zero until the MCL or THR is reached.

[0012] Figure 3 shows a portion of the middle ear anatomy in greater detail, including the incus 301 and the stapes 302. The lenticular process end of the incus 301 vibrates the head 305 of the stapes 302, which in turn vibrates the base 303 of the stapes 302 which couples the vibration into the inner ear (cochlea). Also connected to the head 305 of the stapes 302 is the stapedial tendon 306 of the stapedius muscle situated within the bone of the pyramidal eminence 307. When a loud noise produces an excessively high sound pressure that could damage the inner ear, the stapedius muscle reflexively contracts to decrease the mechanical coupling of the incus 301 to the stapes 302 (and thereby also reduce the force transmission). This protects the inner ear from excessively high sound pressures.

[0013] Medically relevant information about the functional capability' of the ear may be obtained by observation of the stapedius reflex. Measurement of the stapedius reflex also is useful for setting and/or calibrating cochlear implants because the threshold of the stapedius reflex is closely correlated to the psychophysical perception of comfortable loudness, the so- called maximal comfort level (MCL), determined in the fitting process described above. Indeed, the stapedius reflex has been shown to be the most reliable objective measure for optimal setting of cochlear implant (CI) parameters.

[0014] The stapedius reflex can be determined in an ambulatory' clinical setting using an acoustic tympanometer that measures the changes in acoustic impedance of the middle ear caused by stapedial muscle contraction in response to loud sounds. The stiffness of the vibrating elements of a middle ear (also called the compliance) is increased when the stapedius reflex has been elicited. During tympanometry' measurements, the outer ear canal is tightly closed by a plug device to define a closed air space between the plug and the tympanic membrane. A tube in the plug provides air from an air pump that is adapted to vary the air pressure within the closed air space relative to the pressure in the middle ear of the patient. The plug also provides a sound source, e.g. a loudspeaker, that is adapted to provide a sound towards the ty mpanic membrane, and a sensor, e.g. a microphone, that is adapted to sense a reflected portion of the sound provided by the sound source that is reflected from the ty mpanic membrane. But performing these tests and measurements is rather difficult and requires quite specialized equipment, high skill levels and significant time from the fitting audiologist, as well as full cooperation of the patient.

[0015] To measure the stapedius reflex intra-operatively, it also is known to use electrodes that are brought into contact with the stapedius muscle to relay to a measuring device the action current and/or action potentials generated, e.g. a measured EMG signal, upon a contraction of the stapedius muscle. But a reliable minimally-invasive contact of the stapedius muscle is difficult because the stapedius muscle is situated inside the bony pyramidal eminence and only the stapedial tendon is accessible from the interior volume of the middle ear.

[0016] Various intraoperative stapedius muscle electrodes are known from US 6,208,882 (incorporated herein by reference in its entirety ), however, these only achieve inadequate contact of the stapedius muscle tissue (in particular upon muscle contraction) and are also very traumatizing. This reference describes one embodiment that uses a ball shape monopolar electrode contact with a simple wire attached to it. That ould be very difficult to surgically position into a desired position with respect to the stapedius tissue and to fix it there allowing for a long-term atraumatic and stable positioning. Therefore the weakness of this type of electrode is that it does not qualify for chronic implantation. In addition, there is no teaching of how to implement such an arrangement with a bipolar electrode with electrode contacts with sufficient space betw een each other to enable bipolar registration.

[0017] Some intraoperative experiments and studies have been conducted with hook electrodes that have been attached at the stapedius tendon or muscle. These electrode designs were only suitable for acute intra-operative tests. Moreover, some single hook electrodes do not allow a quick and easy placement at the stapedius tendon and muscle — the electrode has to be hand held during intra-operative measurements, while other double hook electrodes do not ensure that both electrodes are inserted into the stapedius muscle due to the small dimensions of the muscle and the flexibility of the electrode tips. One w eakness of these intraoperative electrodes is that they do not qualify for chronic implantation.

[0018] German patent DE 10 2007 026 645 (incorporated herein by reference in its entirety) discloses a tw o-part bipolar electrode configuration where a first electrode is pushed onto the stapedius tendon or onto the stapedius muscle itself, and a second electrode is pierced through the first electrode into the stapedius muscle. One disadvantage of the described solution is its rather complicated handling in the very limited space of the surgical operation area, especially manipulation of the fixation electrode. In addition, the piercing depth of the second electrode is not controlled so that trauma can also occur with this approach. Also it is not easy to avoid galvanic contact between both electrodes.

[0019] U.S. Patent Publication 20100268054 (incorporated herein by reference in its entirety) describes a different stapedius electrode arrangement having a long support electrode with a base end and a tip for insertion into the target tissue. A fixation electrode also has a base end and a tip at an angle to the electrode body. The tip of the fixation electrode passes perpendicularly through an electrode opening in the support electrode so that the tips of the support and fixation electrodes penetrate into the target tissue so that at least one of the electrodes senses electrical activity in the target stapedius tissue. The disadvantages of this design are analogous to the disadvantages mentioned in the preceding patent.

[0020] U.S. Patent Publication 20130281812 (incorporated herein by reference in its entirety) describes a double tile stapedial electrode for bipolar recording. The electrode is configured to be placed over the stapedius tendon and a sharp tip pierces through the bony channel towards the stapedius muscle. The downside of this disclosure is again its rather complicated handling in the very limited space of the surgical operation area.

[0021] Various other stapedial electrode designs also are known, all with various associated drawbacks; for example, US 2011/0255731, US 2014/0100471, US 8280480, and US 8521250, all incorporated herein by reference in their entireties. A simple wire and ball contact electrode is very difficult to surgically position and to keep it atraumatically stabilized for chronic implantations. The penetrating tip of such a design must be stiff enough to pass through the bone tunnel, but if the tip is too stiff, it is difficult to bend and maneuver the wire into its position. And some stapedius muscle electrode designs are only monopolar electrodes (with a single electrode contact) and are not suitable for a bipolar arrangement with the electrode contacts with sufficient distance between each other to enable bipolar registration. Finally, another design is disclosed in co-pending U.S. Provisional Patent Application 62/105,260 (incorporated herein by reference in its entirety).

[0022] US 10,772,563. which is hereby incorporated herein by reference in its entirety) is similar to a tympanometer. here a probe tone is applied on the external ear canal, but instead of measuring the reflected sound (e g. by using a tympanometer), a Middle-Ear sensor detects the transmitted signal via a pressure sensor (e.g., Microphone or P-Sensor). More particularly, a probe tone is applied in the external ear canal, then a pressure sensor in the middle ear senses the sound transmitted though the tympanic membrane (a normal tympanometer measures the reflected sound). The sensed pressure response in an idle state (i.e., no electrical stimulation applied to a cochlear implant electrode contact) is compared to a response observed during stimulation (i.e., an electrical stimulation is applied to a cochlear implant electrode contact). An analysis is performed of the sound levels and frequency characteristics of the response signals, and if the stimulation response is different enough to the pre-stimuli (idle) response, it is categorized as a stapedius reflex. However, this approach requires an external probe tone and the extraction of sound levels and/or frequency characteristics (including high frequencies).

Summary of the Embodiments

[0023] In accordance with an embodiment of the invention, a system for utilizing middle ear pressure of a recipient patient is provided. The system includes a pressure sensor configured to be placed in a middle ear of the patient, the pressure sensor providing a pressure signal indicative of pressure in the middle ear. A controller is configured to receive the pressure signal, and determine an output signal based at least on the pressure signal and without requiring an acoustic stimulus. The output signal may be a heart rate, a heart rate variability, a middle ear pressure, a blood pressure, an eustachian tube function, and/or an occurrence of a stapedius reflex response.

[0024] In accordance with related embodiments of the invention, determining the output signal may include determining an average template of the pressure signal, and subtracting the average template of the pressure signal from the pressure signal.

[0025] In accordance with related embodiments of the invention, the system may be for fitting a cochlear implant implanted in the ear of the recipient patient, the cochlear implant including an implanted electrode array with a plurality of stimulation contacts for delivering electrical stimulation signals to adjacent cochlear tissue. The controller is further configured to: provide a trigger signal causing an electrical stimulation signal in a given stimulation contact to be provided to the ear, the electrical stimulation signal having a stimulus intensity; obtain a stimulation response from the pressure signal upon providing the electrical stimulation signal; and determine if a stapedius reflex response occurs based on the stimulation response. [0026] In accordance with further related embodiments of the invention, the controller may be further configured to: determine an average template of the pressure signal without the stimulation response; and subtract the average template of the pressure signal from the stimulation response when determining if the stapedius reflex occurs. The controller may be further configured to obtain a heartbeat of the patient from the pressure signal and/or receive an alternative heart signal; and provide the trigger signal based, at least in part, on the heartbeat. The alternative heart signal is an electrocardiogram. The trigger signal may occur a predefined time after an R-peak of the heartbeat. The predefined time may be Vi a duration of a heartbeat.

[0027] In still further related embodiments of the invention, the controller may be further configured to: when the stapedius reflex response occurs, identify the MCL for the given stimulation contact based on the corresponding stimulus intensity; and when the stapedius reflex response does not occur, increase the stimulus intensity and repeat providing a trigger signal, measuring a stimulation response from the pressure signal upon providing the electrical stimulation signal, and determining if a stapedius reflex response occurs. The controller may be configured to send the MCL to the cochlear implant, whereby the cochlear implant is fitted with the MCL for the given stimulation contact.

[0028] In accordance with another embodiment of the invention, a method of utilizing middle ear pressure of a recipient patient is provided. The method includes obtaining a pressure signal indicative of pressure in the middle ear. Based at least on the pressure signal and without requiring an acoustic stimulus, an output signal is determined. The output signal may be a heart rate, a heart rate variability, a middle ear pressure, a blood pressure, an eustachian tube function, and/or an occurrence of a stapedius reflex response.

[0029] In accordance with related embodiments of the invention, determining the output signal may include determining an average template of the pressure signal, and subtracting the average template of the pressure signal from the pressure signal.

[0030] In accordance with related embodiments of the invention, the method further may include fitting a cochlear implant implanted in the ear of the recipient patient. The cochlear implant includes an implanted electrode array with a plurality of stimulation contacts for delivering electrical stimulation signals to adjacent cochlear tissue, The fitting may include providing a trigger signal causing an electrical stimulation signal in a given stimulation contact to be provided to the ear, the electrical stimulation signal having a stimulus intensity. A stimulation response is obtained from the pressure signal upon providing the electrical stimulation signal. A determination is made whether a stapedius reflex response occurred based on the stimulation response. The method may further include determining an average template of the pressure signal without the stimulation response; and subtracting the average template of the pressure signal from the stimulation response when determining if the stapedius reflex occurs. The method may further include determining a heartbeat of the patient from the pressure signal and/or from an alternative heart signal source; and providing the trigger signal based, at least in part, on the heartbeat. The alternative heart signal source may be an electrocardiogram. Providing the trigger signal may include providing the trigger signal a predefined time after a R-peak of the heartbeat.

[0031] In accordance with further related embodiments of the invention, the method may further include when the stapedius reflex response occurs, identifying the MCL for the given stimulation contact based on the corresponding stimulus intensity. When the stapedius reflex response does not occur, increasing the stimulus intensity and repeating providing a trigger signal, measuring a stimulation response from the pressure signal upon providing the electrical stimulation signa, and determining if a stapedius reflex response occurs. The MCL may be sent to the cochlear implant, whereby the cochlear implant is fitted with the MCL for the given stimulation contact.

[0032] In accordance with another embodiment of the invention, a non-transitory tangible computer program product in a computer-readable medium for fitting a cochlear implant implanted in the ear of the recipient patient without requiring an acoustic stimulus is provided. The cochlear implant includes an implanted electrode array with a plurality of stimulation contacts for delivering electrical stimulation signals to adjacent cochlear tissue. The product includes program code for receiving a pressure signal from a pressure sensor placed in a middle ear of the patient; program code for determining a heartbeat of the patient from the pressure signal and/or from an alternative heart signal source; program code for providing a trigger signal, based at least in part, on the heartbeat, causing an electrical stimulation signal in a given stimulation contact to be provided to the ear, the electrical stimulation signal having a stimulus intensity; program code for obtaining a stimulation response from the pressure signal upon providing the electrical stimulation signal; and program code for determining if a stapedius reflex response occurred based on the stimulation response, wherein determining includes determining an average template of the pressure signal without the stimulation response; and subtracting the average template of the pressure signal from the stimulation response when determining if the stapedius reflex occurs.

[0033] In accordance with related embodiments of the invention, the computer program product may further include program code for, when the stapedius reflex response occurs, identifying the MCL for the given stimulation contact based on the corresponding stimulus intensity; and program code for, when the stapedius reflex response does not occur, increasing the stimulus intensity and repeating providing a trigger signal, measuring a stimulation response from the pressure signal upon providing the electrical stimulation signa, and determining if a stapedius reflex response occurs. The computer product code may further include program code for sending the MCL to the cochlear implant, whereby the cochlear implant is fitted with the MCL for the given stimulation contact.

Brief Description of the Drawings

[0034] The foregoing features of embodiments will be more readily understood by reference to the following detailed description, taken with reference to the accompanying drawings, in which:

[0035] Figure 1 shows anatomical structures in a human ear having a cochlear implant system;

[0036] Figure 2 show s a block diagram of a cochlear implant fitting system configured to perform a conventional post-implantation fitting;

[0037] Figure 3 shows a portion of the middle ear anatomy;

[0038] Figures 4A-B shows tympanic membrane movement due to contraction of the stapedius muscle. Figure 4A shows the membrane moving to the outwards, while Figure 4B shows the membrane moving to the inwards;

[0039] Figure 5 show s how' the filling of blood vessels can push the middle ear w alls in (left side), and when the blood moves out it increases the volume of the middle ear walls (right side); [0040] Figures 6A-6C shows various sensor arrangements for measuring pressure and or the occurrence of the stapedius reflex response in the middle ear of a patient with a cochlear implant according to embodiments of the present invention;

[0041] Figure 7 is a process flow diagram of an exemplary methodology of utilizing middle ear pressure of a recipient patient, in accordance with an embodiment of the invention;

[0042] Figure 8 shows an example of a heartbeat extraction in an ECG triggered system, in accordance with an embodiment of the invention;

[0043] Figure 9 shows a block diagram of a system for utilizing middle ear pressure of a recipient patient, in accordance with an embodiment of the invention; and

[0044] Figure 10 shows a sequence of stimuli at 500Hz and increasing intensity from 80dB to 11 OdB (columns), in accordance with an embodiment of the invention.

Detailed Description of Specific Embodiments

[0045] In illustrative embodiments, a pressure sensor located in the middle ear provides a pressure signal used to determine, without requiring an acoustic stimulus, a heart rate, a heart rate variability, a middle ear pressure, a blood pressure, an eustachian tube function, and/or a stapedius reflex response. The detection of the stapedius reflex response may be used as an objective indication for determining Most Comfortable Loudness levels when fitting a cochlear implant. Details are described below.

[0046] The middle ear is a sealed cavity which ventilates only when the eustachian tube opens to equalize to the atmospheric pressure. Being a sealed chamber, any change in the middle ear volume produces a transient change in the overall pressure. Figures 4A-B show the stapes 401, the incus 402, malleus 403, and the tympanic membrane 404 movement (dotted line) due to contraction of the stapedius muscle. The direction of the movement of the tympanic membrane may depend on the individual - Figure 4A shows the membrane moving to the towards the ear canal, while Figure 4B shows the membrane moving to the towards the middle ear. When the stapedius reflex is activated and the stapedius muscle contracts, the contraction is transmitted through the ossicles and ultimately moves the tympanic membrane. The movement of the tympanic membrane will then temporarily make a small change in the middle ear pressure. [0047] In accordance with various embodiments of the invention, a measurement system and methodology is presented based on the pressure change in the middle ear pressure, without requiring an acoustic stimulus (see, for example, US 10,772,563, described above, where a probe tone is applied in the external ear canal, then a pressure sensor in the middle ear senses the sound transmitted though the tympanic membrane (a normal tympanometer measures the reflected sound), and then compare this idle state to the response observed during a stimulation). Such changes may be derived from the movement of the middle ear structures, such as the tympanic membrane when the stapedius muscle or tensor tympani contract, as described above.

[0048] Additionally, if the middle ear is properly sealed, the pressure sensor provides the capability to detect heartbeat cycles. The signal produced by the pressure sensor is largely caused by blood pumping through the middle ear walls, causing cyclic volume and thus pressure changes in the enclosed space of the middle ear. Figure 5 shows how the filling of blood vessels can push the middle ear walls in (left side), and when the blood moves out it increases the volume (right), causing a pressure cycle. This cyclic signal, which reflects a person’s heartbeat, typically has a magnitude much higher than the changes produced by the stapedius reflex activation, and therefore has the potential to reduce the sensibility of such a measurement. However, this signal is rhythmic, and in various embodiments of the invention, can be averaged over time, and then subtracted out of the pressure signal such that the stapedius reflex can be more easily detected. Furthermore, there is a particular interval in each phase of the blood flow signal, in which the deviation from the average signal is particularly low. Thus, this interval can advantageously be used to send a stimulus (e.g., an electrical stimulus using a cochlear implant electrode) to trigger/ detect the occurrence of a stapedius reflex, as described in more detail below.

[0049] Figures 6A-6C shows various specific sensor arrangements for measuring pressure and or the occurrence of the stapedius reflex response in the middle ear of a patient with a cochlear implant according to embodiments of the present invention. In Figure 6A, the sensor 600 is a pressure sensor configured to sense the pressure response characteristics via diffusion sensing of the free space of the middle ear. In the embodiment shown in Fig. 6A. the response sensor 600 branches off from the main body of the electrode lead on a separate stalk. Figure 6C shows another embodiment with a pressure sensor 600 that is integrated onto the outer surface of the electrode lead in the middle ear. Fig. 6B shows an embodiment that uses a pressure sensor as the response sensor 600 that is directly engaged in contact with the ossicles so as to sense the changing response characteristics directly via conduction sensing of the ossicles as they are clamped by the stapedius reflex.

[0050] Figure 7 is a process flow diagram of an exemplary methodology of utilizing middle ear pressure of a recipient patient, in accordance with an embodiment of the invention. In particular, the methodology shown in Figure 7 is directed to an embodiment for fitting a cochlear implant (e.g., an MCL value) based on detecting the stapedius reflex in a patient. The cochlear implant includes an implanted electrode array with a plurality of stimulation contacts for delivering electrical stimulation signals to adjacent cochlear tissue.

[0051] The pressure in the middle ear is measured, step 701. This is accomplished by utilizing a pressure sensor placed in the middle ear, as discussed above. An average of the measured pressure signal is then calculated, step 703. The average pressure may reflect, without limitation, the patient’s heartbeat, which may be relatively large in magnitude compared to, for example, the stapedius reflex response. In ty pical embodiments the pressure signal is thus cyclic, and the average may be provided as a template synchronized over one or more cycles of the heartbeat. Note that the average may be utilized separately, without limitation, as an ECG. A trigger signal is provided causing an electrical stimulation signal, having a stimulus intensity, in a given stimulation contact of the cochlear implant, step 705. For example, the trigger signal may be provided approximately 500 ms after an R-Peak of a heartbeat, as discussed in more detail below. A stimulation response from the pressure signal is obtained upon providing the electrical stimulation signal, step 707, from which the average pressure is subtracted, step 709. This subtraction advantageously deletes the relatively large magnitude of the patient’s heartbeat from the stimulation response, allowing for easier detection of the stapedius reflex response. It can then be determined whether a stapedius response occurred, step 711. If the stapedius response has occurred, the MCL for the given electrode contact can be set based on the provided stimulus intensity, and programmed into the cochlear implant, step 713. If the stapedius reflex response was not detected, increase the stimulus intensity and continue at step 705.

[0052] In illustrative embodiments of the invention, a heartbeat-sync recording system may be utilized to increase the system sensitivity. The system may use, for example, either the pressure signal or an ECG recording to monitor and identity' the heartbeat. When a heartbeat (e.g., pressure peak, or R-Peak) is detected, the system will trigger the electrical stimulation signal. Ideally the stimulation will start approximately 200-500ms (or approximately ! the duration of a heartbeat cycle) after the R-peak. where the pulse shape is more stable and where a linear decrease occurs. Stimulating on this part of the pulse will make easier to observe changes in the pressure.

[0053] Figure 8 shows an example of a heartbeat extraction in an ECG triggered system, in accordance with an embodiment of the invention. Show n in the left graph is the pressure signal after an electrical stimulation (dark line is the average, lighter lines are different repetitions). Show n in the center graph is a template of the average pressure signal without the electrical stimulation, which is synced with an R-peak on an ECG. The template of the average pressure (typically reflecting the heartbeat) may be recorded before the electrical stimulation occurs, or a period after which the response from the electrical stimulation has settled down. On the right is a graph showing the pressure signal after an electrical stimulation, with the average pressure signal (e.g., the heartbeat) subtracted.

[0054] As illustrated in the center graph in Figure 8, the trigger signal initiating the electrical stimulation signal occurs roughly 500ms after the R-peak (i.e., when the heartbeat signal is more stable and where a linear decrease occurs). The average (template) of the heartbeat is extracted from each stimulus (i.e., the right graph in Figure 8), leaving a cleaner signal. In the example shown, it can be observed in the right graph of Figure 8 that there are some residual peaks 801 still derived from the main artefact, but the peak in the middle comes from the linear part, and therefore is something associated with the stimulus (e g., stapedius reflex).

[0055] An added benefit of this methodology is that the heartbeat may also provide meaningful health information as the heart rate and heart rate variability. Also, the actual pressure of the middle ear can advantageously be monitored, which is another health indicator to determine whether the ear is healthy (normally, it should be around atmospheric pressure). In addition, with the magnitude of the heartbeat and the average middle ear pressure, the blood pressure can be estimated. Finally, under a stable recording, the opening of the eustachian tube can be recognized as a huge pressure fluctuation and is thus clearly detectable and quantifiable. Additional embodiments can thus include the monitoring of the:

• Heart rate

• Heart rate variability

• Middle ear pressure

• Blood pressure Eustachian tube function (detection of equalization periods)

[0056] Figure 9 shows a block diagram of a system for utilizing middle ear pressure of a recipient patient, in accordance with an embodiment of the invention. A pressure transducer 901 in the middle ear provides a pressure signal. This pressure signal may then be used to detect the heartbeat to trigger the electrical stimulation signal, although other signals like ECG 903 can also be used for that purpose. Illustratively, a controller may be configured to receive/detect the heartbeat 905 from the pressure signal or ECG, and trigger 907 a stimulus 909 from the pressure signal, which many be an electrical and/or an acoustic stimulation signal. Furthermore, the controller may filter the measured pressure 911, extract the average pressure from the pressure signal, detect the stapedius reflex and/or control fitting of the cochlear implant 913, and provide other health metrics 915. As described above, the onset of each heartbeat cycle may be used to calculate an average shape of the heartbeat and subtract it from the pressure signal to filter it out. In addition, the same information could provide the heart rate and heart rate variability. Further combining it with the medium Middle Ear Pressure (MEP), the blood pressure (BP) may be calculated. Although the heartbeat synchronization is optional (dotted lines), it increases the resolution of the system.

[0057] The system and methodology described above has been shown effective and has similar thresholds when compared to the use of a commercial tympanometer. Figure 10 shows a sequence of stimuli at 500Hz and increasing intensity from 80dB to 1 lOdB (columns), in accordance with an embodiment of the invention. The first row shows the response of a commercial tympanometer, the second row shows the ECG signal used to synchronize the stimulus (it is noisy but the R-peak is clearly shown at -500ms), the third row shows the pressure (filtered in the spectrum l-20Hz), and the last row shows again the pressure after extracting the pattern of the heartbeat. It is observed that there is a reflex already at 95 dB (1^st row). On the third row, the curve on the shadowed gets visually bigger at 105dB or lOOdB. Finally, in the post-processed pressure (4^th row), it is clear how the pressure signal shows some activity already from 95dB.

[0058] Embodiments of the invention may be implemented in part in any conventional computer programming language. For example, preferred embodiments may be implemented in a procedural programming language (e.g.. “C”) or an object-oriented programming language (e.g., '‘C++’’, Python). Alternative embodiments of the invention may be implemented as pre-programmed hardware elements, other related components, or as a combination of hardware and software components.

[0059] Embodiments can be implemented in part as a computer program product for use with a computer system. Such implementation may include a series of computer instructions fixed either on a tangible medium, such as a computer readable medium (e.g., a diskette, CD-ROM, ROM, or fixed disk) or transmittable to a computer system, via a modem or other interface device, such as a communications adapter connected to a network over a medium. The medium may be either a tangible medium (e.g., optical or analog communications lines) or a medium implemented with wireless techniques (e.g., microwave, infrared or other transmission techniques). The series of computer instructions embodies all or part of the functionality previously described herein with respect to the system. Those skilled in the art should appreciate that such computer instructions can be written in a number of programming languages for use with many computer architectures or operating systems. Furthermore, such instructions may be stored in any memory device, such as semiconductor, magnetic, optical or other memory devices, and may be transmitted using any communications technology, such as optical, infrared, microwave, or other transmission technologies. It is expected that such a computer program product may be distributed as a removable medium with accompanying printed or electronic documentation (e.g., shrink wrapped software), preloaded with a computer system (e.g., on system ROM or fixed disk), or distributed from a server or electronic bulletin board over the network (e.g., the Internet or World Wide Web). Of course, some embodiments of the invention may be implemented as a combination of both software (e.g., a computer program product) and hardware. Still other embodiments of the invention are implemented as entirely hardware, or entirely software (e.g., a computer program product).

[0060] Although various exemplary embodiments of the invention have been disclosed, it should be apparent to those skilled in the art that various changes and modifications can be made which will achieve some of the advantages of the invention without departing from the true scope of the invention.

Claims

CLAIMS What is claimed is:

1. A system for utilizing middle ear pressure of a recipient patient, the system comprising: a pressure sensor configured to be placed in a middle ear of the patient, the pressure sensor providing a pressure signal indicative of pressure in the middle ear; a controller configured to: receive the pressure signal; determine, based at least on the pressure signal and without requiring an acoustic stimulus, an output signal selected from the group consisting of heart rate, heart rate variability, middle ear pressure, blood pressure, eustachian tube function, an occurrence of a stapedius reflex response and combinations thereof.

2. The system according to claim 1 wherein the controller is further configured to: determine an average template of the pressure signal; and subtract the average template of the pressure signal from the pressure signal when determining the output signal.

3. The system according to claim 1, wherein the system is for fitting a cochlear implant implanted in the ear of the recipient patient, the cochlear implant including an implanted electrode array with a plurality of stimulation contacts for delivering electrical stimulation signals to adjacent cochlear tissue, wherein the controller is further configured to: provide a trigger signal causing an electrical stimulation signal in a given stimulation contact to be provided to the ear, the electrical stimulation signal having a stimulus intensity’; obtain a stimulation response from the pressure signal upon providing the electrical stimulation signal; and determine if a stapedius reflex response occurs based on the stimulation response.

4. The system according to claim 3. wherein the controller is further configured to: determine an average template of the pressure signal without the stimulation response; and subtract the average template of the pressure signal from the stimulation response when determining if the stapedius reflex occurs.

5. The system according to claim 3, wherein the controller is further configured to: obtain a heartbeat of the patient from the pressure signal and/or receive an alternative heart signal; and provide the trigger signal based, at least in part, on the heartbeat.

6. The system according to claim 5, wherein the alternative heart signal is an electrocardiogram.

7. The system according to claim 5. wherein the trigger signal occurs a predefined time after a R-peak of the heartbeat or pressure peak.

8. The system according to claim 7. wherein the predefined time is '/i a duration of a heartbeat cycle.

9. The system according to claim 3, wherein the controller is further configured to: when the stapedius reflex response occurs, identify the MCL for the given stimulation contact based on the corresponding stimulus intensity; and when the stapedius reflex response does not occur, increase the stimulus intensity and repeat providing a trigger signal, measuring a stimulation response from the pressure signal upon providing the electrical stimulation signa, and determining if a stapedius reflex response occurs.

10. The system according to claim 9, wherein the controller is configured to send the MCL to the cochlear implant, whereby the cochlear implant is fitted with the MCL for the given stimulation contact.

11. A method of utilizing middle ear pressure of a recipient patient, the method comprising: obtaining a pressure signal indicative of pressure in the middle ear; and determining, based at least on the pressure signal and without requiring an acoustic stimulus, an output signal selected from the group consisting of of heart rate, heart rate variability , middle ear pressure, blood pressure, eustachian tube function, an occurrence of a stapedius reflex response and combinations thereof.

12. The method according to claim 1 1 , further including: determining an average template of the pressure signal; and subtracting the average template of the pressure signal from the pressure signal when determining the output signal.

13. The method according to claim 11, wherein the method further includes fitting a cochlear implant implanted in the ear of the recipient patient, the cochlear implant including an implanted electrode array with a plurality of stimulation contacts for delivering electrical stimulation signals to adjacent cochlear tissue, wherein fitting includes: providing a trigger signal causing an electrical stimulation signal in a given stimulation contact to be provided to the ear, the electrical stimulation signal having a stimulus intensity; obtaining a stimulation response from the pressure signal upon providing the electrical stimulation signal; and determining if a stapedius reflex response occurred based on the stimulation response.

14. The method laccording to claim 13, wherein the method further includes: determining an average template of the pressure signal without the stimulation response; and subtracting the average template of the pressure signal from the stimulation response when determining if the stapedius reflex occurs.

15. The method according to claim 13, wherein the method further includes: determining a heartbeat of the patient from the pressure signal and/or from an alternative heart signal source; and providing the trigger signal based, at least in part, on the heartbeat.

16. The method according to claim 15, wherein the alternative heart signal source is an electrocardiogram.

17. The method according to claim 15, wherein providing the trigger signal includes providing the trigger signal a predefined time after a R-peak of the heartbeat or pressure peak.

18. The method according to claim 13, the method further comprising: when the stapedius reflex response occurs, identifying the MCL for the given stimulation contact based on the corresponding stimulus intensity; and when the stapedius reflex response does not occur, increasing the stimulus intensity and repeating providing a trigger signal, measuring a stimulation response from the pressure signal upon providing the electrical stimulation signa, and determining if a stapedius reflex response occurs.

19. The method according to claim 18. the method further comprising sending the MCL to the cochlear implant, whereby the cochlear implant is fitted with the MCL for the given stimulation contact.

20. A non-transitory tangible computer program product in a computer-readable medium for fitting a cochlear implant implanted in the ear of the recipient patient, the cochlear implant including an implanted electrode array with a plurality of stimulation contacts for delivering electrical stimulation signals to adjacent cochlear tissue, the product comprising: program code for receiving a pressure signal from a pressure sensor placed in a middle ear of the patient; program code for determining a heartbeat of the patient from the pressure signal and/or from an alternative heart signal source; program code for providing a trigger signal, based at least in part, on the heartbeat, causing an electrical stimulation signal in a given stimulation contact to be provided to the ear, the electrical stimulation signal having a stimulus intensity; program code for obtaining a stimulation response from the pressure signal upon providing the electrical stimulation signal; and program code for determining if a stapedius reflex response occurred based on the stimulation response, wherein determining includes: determining an average template of the pressure signal without the stimulation response; and subtracting the average template of the pressure signal from the stimulation response when determining if the stapedius reflex occurs.

21. The computer program product according to claim 20, the product further comprising: program code for, when the stapedius reflex response occurs, identifying the MCL for the given stimulation contact based on the corresponding stimulus intensity; and program code for, when the stapedius reflex response does not occur, increasing the stimulus intensify and repeating providing a trigger signal, measuring a stimulation response from the pressure signal upon providing the electrical stimulation signa, and determining if a stapedius reflex response occurs.

22. The computer product code according to claim 21, the product further comprising program code for sending the MCL to the cochlear implant, whereby the cochlear implant is fitted with the MCL for the given stimulation contact.