Bionic ear programming system

[0001] The present application claims the benefit of U.S. Provisional Application Ser. No. 60/313,225, filed Aug. 17, 2001, which application is incorporated herein by reference.

[0002] The present invention relates to cochlear implants, and more particularly to a bionic ear programming system that may be used with the more sophisticated and complex cochlear implants that are now available.

[0003] Electrical stimulation of predetermined locations within the cochlea of the human ear through an intra-cochlear electrode array is described, e.g., in U.S. Pat. No. 4,400,590. The electrode array shown in the '590 patent comprises a plurality of exposed electrode pairs spaced along and imbedded in a resilient curved base for implantation in accordance with a method of surgical implantation, e.g., as described in U.S. Pat. No. 3,751,615. The system described in the '590 patent receives audio signals, i.e., sound waves, at a signal processor (or speech processor) located outside the body of a hearing impaired patient. The speech processor converts the received audio signals into modulated RF data signals that are transmitted by a cable connection through the patient's skin to an implanted multi-channel intracochlear electrode array. The modulated RF signals are demodulated into analog signals and are applied to selected ones of the plurality of exposed electrode pairs in the intra-cochlear electrode so as to electrically stimulate predetermined locations of the auditory nerve within the cochlea.

[0004] A new, more sophisticated, class of cochlear implant, referred to as a bionic ear, is now available to provide patients with enhanced hearing performance. For example, Advanced Bionics Corporation, of Sylmar Calif., currently offers a cochlear implant which it refers to as the CII Bionic Ear™ cochlear implant. Many features associated with the CII Bionic Ear implant are described in U.S. Pat. No. 6,219,580, incorporated herein by reference. Advantageously, with the CII Bionic Ear™ cochlear implant, more than twice as much sound can be captured, and 10 times more processing power is available to process such sound. Further, the CII Bionic Ear implant contains internal memory banks that enable it to send very detailed, high resolution sound signals to the auditory nerve. Such signals are delivered to the auditory nerve using a special electrode adapted to be inserted into the cochlea. A representative electrode usable with the CII Bionic ear is described in U.S. Pat. No. 6,129,753, also incorporated herein by reference.

[0005] Other improved features of cochlear implant systems are taught, e.g., in U.S. Pat. Nos. 5,626,629; 6,067,474; 6,157,861; 6,219,580; 6,249,704; and 6,289,247, each of which patents is incorporated herein by reference.

[0006] Advantageously, the implantable cochlear stimulators described in the '629, '474, '861, '580 and '704 patents are able to selectively control the pulse width of stimulating pulses that are applied through the electrode array to the cochlea, and the frequency at which the stimulating pulses are applied.

[0007] As the art of cochlear stimulation has advanced, the implanted portion of the cochlear stimulation system, and the externally wearable processor (or speech processor), if used (much of the circuitry previously employed in the externally wearable processor has been moved to the implanted portion, thereby reducing the amount of information that must be transmitted from the external wearable processor to the implanted portion), have become increasingly complicated and sophisticated. The amount of control and discretion exercisable by an audiologist in selecting the modes and methods of operation of the cochlear stimulation system have increased dramatically and it is no longer possible to fully control and customize the operation of the cochlear stimulation system through the use of, for example, switches located on the speech processor. As a result, it has become necessary to utilize an implantable cochlear stimulator fitting system to establish the operating modes and methods of the cochlear stimulation system and then to download such programming into the speech processor. One such fitting system is described in the '629 patent. An improved fitting system is described in the '247 patent. The present invention is directed to a still further improved fitting system that may be used with a bionic ear cochlear implant.

[0008] The '247 patent further highlights representative stimulation strategies that may be employed by a multichannel stimulation system. Such strategies represent the manner or technique in which the stimulation current is applied to the electrodes of an electrode array used with the stimulation system. Such stimulation strategies, all of which apply current pulses to selected electrodes, may be broadly classified as: (1) sequential or non-simultaneous (where only one electrode receives a current pulse at the same time); (2) simultaneous (where substantially all of the electrodes receive current stimuli at the same time, thereby approximating an analog signal); or (3) partially simultaneous pulsitile stimulation (where only a select grouping of the electrodes receive stimuli at the same time in accordance with a predefined pattern).

[0009] Typically, when the fitting systems described in the '629 or '247 patents are employed for multichannel stimulation systems, or when equivalent or similar fitting systems are employed, it is necessary to use directly measured threshold values and/or thresholds derived from the measurement of phsycophysically-determined psuedo-comfort levels. That is, for each channel of the multichannel system, a minimum threshold level is measured, typically referred to as a “T” level, which represents the minium stimulation current which when applied to a given electrode associated with the channel produces a sensed perception of sound at least 50% of the time. In a similar manner, an “M” level is determined for each channel, which represents a stimulation current which when applied to the given electrode produces a sensed perception of sound that is moderately loud, or comfortably loud, but not so loud that the perceived sound is uncomfortable. These “T” and “M” levels are then used by the fitting software in order to properly map sensed sound to stimulation current levels that can be perceived by the patient as sound.

[0010] Disadvantageously, determining the “T” and/or “M” levels (or other required thresholds) associated with each channel of a multichannel stimulation system is an extremely laborious and time-intensive task. Such determinations require significant time commitments on the part of the clinician, as well as the patient. Moreover, once determined one channel at a time, such levels may not be representative of actual threshold levels that are present during real speech.

[0011] The present invention provides a Bionic Ear Programming System (BEPS) that provides access to the full functionality of a bionic ear implant, such as the CII Bionic Ear™ implant made by Advanced Bionics Corporation. Equally important, the BEPS of the present invention supports a much more complex device than previous programming systems from the point of view of a clinician fitting the patient.

[0012] The added complexity provided in a bionic ear implant, such as the CII Bionic Ear™ implant, includes higher numbers of channels, arbitrary simultaneous grouping, intra-phase gaps, binaural capabilities, and the like. Fortunately, the BEPS deals with all of this added complexity in a way that makes the new, more complex bionic ear implant, seem easier to use and fit. That is, while the BEPS adds tools to take advantage of the increased functionality of the implant, such tools are fashioned to help the clinician fit a patient faster and more accurately than has heretofore been possible. For example, rather than expanding the process of setting T's and M's into a multi-window workflow, all of this functionality has been included in a single window. Additionally, such single functionality within one single window is segmented into an easy-to-use 3-part workflow, as explained hereinafter.

[0013] In accordance with one aspect of the invention, the BEPS automatically finds and removes broken electrodes, thereby preventing stimulation on such electrodes, and thereby further eliminating the need for the clinician to measure impedances and manually remove such broken electrodes. The result is a much more safer programming system.

[0014] It is a feature of the present invention to provide a programming system that automatically sorts out bad electrodes, reduces fitting times and improves patient performance.

[0015] It is yet another feature of the invention to provide a programming system that automatically generates customized programming templates that a clinician may use to quickly fit a given patient.

[0016] It is an additional feature of the invention to provide a programming system that allows clinicians to quickly run (unattended) wired speech understanding tests that provide objective rather than subjective programming choices.

[0021] Appendix A, incorporated herein by reference, provides an overview of various features associated with the BEPS of the present invention.

[0022] Corresponding reference characters indicate corresponding components throughout the several views of the drawings.

[0023] The following description is of the best mode presently contemplated for carrying out the invention. This description is not to be taken in a limiting sense, but is made merely for the purpose of describing the general principles of the invention.

[0024] Turning first to FIG. 1A, a bionic ear cochlear stimulation system is shown that includes a speech processor portion 10 and a cochlear stimulation portion 12. The speech processor portion 10 includes a speech processor (SP) 16 and a microphone 18. The microphone 18 may be connected directly to the SP 16, or may be coupled to the SP 16 through an appropriate communication link 24. The cochlear stimulation portion 12 includes an implantable cochlear stimulator (ICS) 21, and an electrode array 48. The electrode array 48 is adapted to be inserted within the cochlea of a patient. The array 48 includes a multiplicity of electrodes, e.g., sixteen electrodes, spaced along its length that are selectively connected to the ICS 21. The electrode array 48 may be substantially as shown and described in U.S. Pat. No. 4,819,647 or 6,129,753, incorporated herein by reference. Electronic circuitry within the ICS 21 allows a specified stimulation current to be applied to selected pairs or groups of the individual electrodes included within the electrode array 48 in accordance with a specified stimulation pattern, defined by the SP 16.

[0025] The ICS 21 and the SP 16 are shown in FIG. 1A as being linked together electronically through a suitable data or communications link 14. In some cochlear implant systems, e.g., prior art systems, the SP 16 and microphone 18 comprise the external portion of the cochlear implant system; and the ICS 21 and electrode array 48 comprise the implantable portion of the system. Thus, the data link 14 is a transcutaneous data link that allows power and control signals to be sent from the SP16 to the ICS 21. In some embodiments, data and status signals may also be sent from the ICS 21 to the SP 16.

[0026] In a typical bionic ear implant system, as shown more particularly below in FIG. 1B, at least certain portions of the SP 16 are included within the implantable portion of the overall cochlear implant system, while other portions of the SP 16 remain in the external portion of the system. In general, at least the microphone 18 and associated analog front end (AFE) circuitry will be part of the external portion of the system; and at least the ICS 21 and electrode array 48 are part of the implantable portion of the invention. As used herein, “external” means not implanted under the skin or residing within the inner ear. However, “external” may mean within the outer ear, including in the ear canal, and may also include within the middle ear.

[0027] Typically, where a transcutaneous data link must be established between the external portion and implantable portions of the system, such link is realized by an internal antenna coil within the implantable portion, and an external antenna coil within the external portion. In use, the external antenna coil is positioned so as to be aligned over the location where the internal antenna coil is implanted, allowing such coils to be inductively coupled to each other, thereby allowing data (e.g., the magnitude and polarity of a sensed acoustic signals) and power to be transmitted from the external portion to the implantable portion. Note, in other embodiments of the invention, both the SP 16 and the ICS 21 may be implanted within the patient, either in the same housing or in separate housings. If in the same housing, the link 14 may be realized with a direct wire connection within such housing. If in separate housings, as taught, e.g., in U.S. Pat. No. 6,067,474, incorporated herein by reference, the link 14 may be an inductive link using a coil or a wire loop coupled to the respective parts.

[0028] The microphone 18 senses acoustic signals and converts such sensed signals to corresponding electrical signals, and may thus be considered as an acoustic transducer. The electrical signals are sent to the SP 16 over a suitable electrical or other link 24. The SP 16 processes these converted acoustic signals in accordance with a selected speech processing strategy in order to generate appropriate control signals for controlling the ICS 21. Such control signals specify or define the polarity, magnitude, location (which electrode pair receives the stimulation current), and timing (when the stimulation current is applied to the electrode pair) of the stimulation current that is generated by the ICS. Such control signals thus combine to produce a desired spatiotemporal pattern of electrical stimuli in accordance with the desired speech processing strategy. Unlike prior art cochlear implant systems, the bionic ear implant system advantageously confines such control signals to circuitry within the implantable portion of the system, thereby avoiding the need to continually send or transmit such control signals across a transcutaneous link.

[0029] The speech processing strategy is used, inter alia, to condition the magnitude and polarity of the stimulation current applied to the implanted electrodes of the electrode array 48. Such speech processing strategy involves defining a pattern of stimulation waveforms that are to be applied to the electrodes as controlled electrical currents. If multiple electrode pairs exist, as is the case with a multichannel cochlear implant system, then the types of stimulation patterns applied to the multiple channels may be conveniently categorized as: (1) simultaneous stimulation patterns, or (2) non-simultaneous stimulation patterns. Simultaneous stimulation patterns may be “fully” simultaneous or partially simultaneous. A fully simultaneous stimulation pattern is one wherein stimulation currents, either analog or pulsitile, are applied to the electrodes of all of the available channels at the same time. A partially simultaneous stimulation pattern is one wherein stimulation currents, either analog or pulsitile, are applied to the electrodes of two or more channels, but not necessarily all of the channels, at the same time. Examples of each type are given in the U.S. Pat. No. 6,289,247, previously incorporated herein by reference.

[0030] Analog waveforms used in analog stimulation patterns are typically reconstructed by the generation of continuous short monophasic pulses (samples). The sampling rate is selected to be fast enough to allow for proper reconstruction of the temporal details of the signal. An example of such a sampled analog stimulation pattern is a simultaneous analog sampler (SAS) strategy.

[0031] Current pulses applied in pulsitile stimulation patterns are generally biphasic pulses, but may also be multiphasic pulses, applied to the electrodes of each channel. The biphasic/multiphasic pulse has a magnitude (e.g., amplitude and/or duration) that varies as a function of the sensed acoustic signal. (A “biphasic” pulse is generally considered as two pulses: a first pulse of one polarity having a specified magnitude, followed immediately, or after a very short delay, by a second pulse of the opposite polarity having the same total charge, which charge is the product of stimulus current times duration of each pulse or phase.) For multichannel cochlear stimulators of the type used with the present invention, it is common to sample the acoustic signal at a rapid rate, and apply a biphasic stimulation pulse in sequence (i.e., non-simultaneously) to each of the pairs of electrodes of each channel in accordance with a specified pattern and cycle time, with the magnitude of the stimulation current being a function of information contained within the sensed acoustic signal at a given (e.g., the most recent) sample time. An example of such sequential, non-simultaneous stimulation pattern is a continuous interleaved sampler (CIS) strategy.

[0032] It is important to recognize that in between the two extremes of fully simultaneous stimulation patterns (wherein analog stimulation currents are continuously applied to all channels, e.g., using the SAS strategy) and non-simultaneous pulsitile patterns (wherein biphasic pules are applied in a specified sequence to all channels without time overlap, e.g., using the CIS strategy), there are a great number of other stimulation patterns that may be formulated. Such other simulation patterns may prove more efficacious for a given patient than either of the SAS or CIS strategies. Thus, an important part of the fitting process is identifying which of several speech processing strategies is most beneficial for a given patient. A bionic ear implant assumes that an appropriate speech processing strategy has been identified, or can be easily identified.

[0033] Returning to FIG. 1B, a partial block diagram of a representative bionic ear cochlear implant is shown. More particularly, FIG. 1B shows a partial functional block diagram of the SP 16 and the ICS 21 of an exemplary bionic ear cochlear implant system. That which is shown in FIG. 1B depicts the functions that are carried out by the SP 16 and the ICS 21. The actual electronic circuitry that is used to carry out these functions is not critical to the present invention. It should also be pointed out that the particular functions shown in FIG. 1B are representative of just one type of signal processing strategy that may be employed (which divides the incoming signal into frequency bands, and independently processes each band). Other signal processing strategies could just as easily be used to process the incoming acoustical signal, and the present invention could still be used to provide added flexibility in specifying the stimulation patterns and waveforms that are selected and used with such additional signal processing strategies.

[0034] A complete description of the partial functional block diagram of the bionic ear implant shown in FIG. 1B is found in U.S. Pat. No. 6,219,580, incorporated herein by reference. It is to be emphasized that the bionic ear functionality shown in FIG. 1B is only representative of one type of exemplary bionic ear implant, and is not intended to be limiting. The details associated with a given bionic ear implant are not critical to the present invention.

[0035] In the manner described in the '580 patent, the bionic ear implant functionally shown in FIG. 1B provides n analysis channels that may be mapped to one or more stimulus channels. That is, the system of FIG. 1B provides a multiplicity of channels, n, wherein the incoming signal is analyzed. The information contained in these n “analysis channels” is then appropriately processed, compressed and mapped in order to control the actual stimulus patterns that will be applied to the patient by the ICS 21 and its associated electrode array 48. The electrode array 48 includes a multiplicity of electrode contacts, connected through appropriate conductors, to respective current generators, or pulse generators, within the ICS. Through these multiplicity of electrode contacts, a multiplicity of stimulus channels, e.g., m stimulus channels, exist through which individual electrical stimuli may be applied at m different stimulation sites within the patient's cochlea.

[0036] While it is common to use a one-to-one mapping scheme between the analysis channels and the stimulus channels, wherein n=m, and the signal analyzed in the first analysis channel is mapped to produce a stimulation current at the first stimulation channel, and so on, it is not necessary to do so. Rather, in some instances, a different mapping scheme may prove beneficial to the patient. For example, assume that n is not equal to m (n, for example, could be at least 20 or as high as 32, while m may be no greater than sixteen, e.g., 8 to 16). The signal resulting from analysis in the first analysis channel may be mapped to the first stimulation channel via a first map link, resulting in a first stimulation site (or first area of neural excitation). Similarly, the signal resulting from analysis in the second analysis channel of the SP may be mapped to the second stimulation channel via a second map link, resulting in a second stimulation site. Also, the signal resulting from analysis in the second analysis channel may be jointly mapped to the first and second stimulation channels via a joint map link. This joint link results in a stimulation site that is somewhere in between the first and second stimulation sites. The “in between site” is sometimes referred to as a virtual stimulation site. Advantageously, this possibility of using different mapping schemes between n SP analysis channels and m ICS stimulation channels to thereby produce a large number of virtual and other stimulation sites provides a great deal of flexibility with respect to positioning the neural excitation areas in a location that proves most beneficial to the patient.

[0037] Still with reference to FIG. 1B, it should be noted that the speech processing circuitry 16 generally includes all of the circuitry from point (C) to point (A). In prior art cochlear implant systems, the entire SP circuitry was housed in a speech processor that was part of the external (or non-implanted) portion of the system. That is, in such prior art systems, only the ICS 21, and its associated electrode array, were implanted, as indicated by the bracket labeled “Imp1” (for “Implant-1”). This means that in such prior art systems, the signal passing through the serial data stream at point (A) is also the signal that must pass through the transcutaneous communication link from the external unit to the implanted unit. Because such signal contains all of the defining control data for the selected speech processing strategy, for all m stimulation channels, it therefore has a fairly high data rate associated therewith. As a result of such high data rate, either the system operation must be slowed down, which is generally not desirable, or the bandwidth of the link must be increased, which is also not desirable because the operating power increases.

[0038] In contrast to prior art systems, a bionic ear implant advantageously puts at least a portion of the speech processor 16 within the implanted portion of the system. For example, a bionic ear implant places the Pulse Table 42 and arithmetic logic unit (ALU) 43 inside of the implanted portion, as indicated by the bracket labeled “Imp2” in FIG. 1B. Such partitioning of the speech processor 16 offers the advantage of reducing the data rate that must be passed from the external portion of the system to the implanted portion. That is, the data stream that must be passed to the implanted portion Imp2 comprises the signal stream at point (B). This signal is essentially the digitized equivalent of the modulation data associated with each of the n analysis channels, and (depending upon the number of analysis channels and the sampling rate associated with each) may be significantly lower than the data rate associated with the signal that passes through point (A). Hence, improved performance without sacrificing power consumption may be obtained with a bionic ear implant.

[0039] It is contemplated that future generations of bionic ear implant systems will incorporate more and more of the speech processor 16 within the implanted portion of the system. For example, a fully implanted speech processor 16 would incorporate all of the SP in the implanted portion, as indicated by the bracket labeled Imp3 in FIG. 1B. Such a fully implanted speech processor would offer the advantage that the data input into the system, i.e., the data stream that passes through point (C), would need only have rate commensurate with the input acoustic signal.

[0040] The BEPS (Bionic Ear Programming System) of the present invention provides access to the full functionality of a bionic ear implant, e.g., the CII Bionic Ear implant. Just as important, however, the BEPS supports a much more complex device than previous systems from the point of view of a clinican fitting a patient using the bionic ear implant. The added complexity of the bionic ear implant includes higher numbers of channels, arbitrary simultaneous grouping, intra-phase gaps, binaural capabilities, and the like. To help deal with this complexity, tools are added to the BEPS that help clinicians fit a patient faster and more accurately. First, rather than expanding the process of setting T's & M's into a multi-window workflow, all of this functionality is placed on one window. Second, the one window where all this functionality is placed is segmented into a 3-part workflow. Such 3-part workflow is illustrated in FIG. 2. See also Appendix A.

[0041] Previous, or earlier-generation programming systems, focused entirely on the Programming Stage. Electrode impedances were painstakingly measured, and displayed to the clinician, as a safety feature to prevent stimulation on broken electrodes. The BEPS of the present invention takes a different approach. This is, the BEPS of the present invention takes the position that displaying impedances so the clinician can turn off electrodes is not the correct approach. Such approach disadvantageously emphasized to the clinician and patient that there was something wrong with the patient's system. It is not unusual to have such a condition on a few contacts in an array. Rather than display such a condition to the clinician and the patient, the BEPS of the present invention automatically handles these types of conditions. This approach is also taken when more sensitive tests are deployed. Eliminating the problem electrodes up front is an essential step to obtaining optimal performance.

[0042] The first part of the 3-part workflow shown in FIG. 2 is the Pre-Evaluation (Pre-Eval) Stage. During this stage, the BEPS focuses on sorting out bad electrode contacts, reducing fitting times, and improving patient performance. The approach taken by the BEPS is very simple: it runs a set of objective tests, and then generates templates that the clinician uses to start fitting. A template is generated for each type of supported strategy (e.g, CIS, PPS, QPS & N of M). A template excludes suspicious electrodes, sets up necessary simultaneous groups, and estimates relative starting T & M levels. Estimates of the T and M levels are made because it has been found, e.g., during testing, that traditional T & M level measurements have not been accurate. Rather, such measurements have required adjustment by a technique called live-speech adjustment that was pioneered in the original windows-based programming system, known as SCLIN for Windows. (See U.S., e.g., U.S. Pat. No. 5,626,629, previously incorporated herein by reference). NRI-measured T & M levels require the same live-speech adjustment that is already a technique in wide-spread use by clinicians. (NRI-measurements, where NRI stands for Neural Response Imaging, are described, e.g., in U.S. Pat. Nos. 6,157,861 and 6,195,585, incorporated herein by reference, and relate, in general, to monitoring a response evoked by application of a stimulus pulse.) Advantageously, by estimating T and M levels, and including such estimates in the templates, much of the live-speech adjustment can be eliminated or minimized.

[0043] The Pre-Eval Stage runs unattended (typically within 5–30 minutes) after an initial setup, and consists of the following steps:

• • [0044] (1) The clinician sets safety levels observing compliance voltage requirements.
  • [0045] (2) An electric field imaging (EFI) test is run to access electrode quality and to eliminate problem electrodes or to notify the clinician if a large percentage of the array is failing a test. The EFI test conditions the array while it is running and runs over and over again until the array measurements stabilize. Such test typically involves, inter alia, determining an RF transfer function at selected operating conditions.
  • [0046] (3) An NRI test is run to check loudness growth on each electrode. Electrodes without loudness growth are eliminated. From this data RELATIVE T & M levels are estimated and reduced for safety purposes.
  • [0047] (4) An AIT (Automatic Electrode Interaction) test is run to estimate the interaction between the electrodes and to assign electrodes into least-interacting groups. This test correlates well to performance. Thus, using this AIT test, a minimum estimated performance score may be provided, setting an objective fitting goal.

[0048] As seen in FIG. 2, after the Pre-Eval stage is complete, the Programming stage may commence. Such Programming stage involves conventional programming techniques and methods, e.g., to set and adjust T and M levels, all of which may be completed much faster and more accurately using the templates that are generated during the Pre-Eval stage.

[0049] The Post-Eval stage invokes automated speech testing material that allows a clinician to quickly run (unattended) wired speech understanding tests to make objective, rather than subjective, programming choices. A patient's choice of strategy based on preference many times results in reduced performance. This is the way most implants have heretofore been programmed. Advantageously, the objective measures provided in the Post-Eval stage allow the clinician to quantitatively assess performance increases in the overall scores of the bionic ear implant. These tests provide optional “information transfer” indexes, that automatically make adjustments to the patient's program, as needed. Also, at least for the time being, the clinician may use his or her knowledge to manually adjust the patient's cochlear implant program appropriately.

[0050] Advantageously, each of the three above-described stages—the pre-evaluation stage, the programming stage, and the post-evaluation stage—may be launched from a single programming window. A representative programming window that may be used for this purpose is described in Appendix A.

[0051] While the invention herein disclosed has been described by means of specific embodiments and applications thereof, numerous modifications and variations could be made thereto by those skilled in the art without departing from the scope of the invention set forth in the claims.