Accessory adapter for cochlear implant system providing simultaneous T-mic and external audio input

A special accessory adapter for use with a BTE device of a cochlear implant (CI) system provides two inputs: a T-Mic input and an auxiliary audio input. Both inputs (the T-Mic input and the auxiliary audio input) are connected to a special mixer circuit integrated into a body of the accessory adapter. The body of the accessory adapter connects to the BTE using the same earhook attachment mechanism used by other accessories used by the CI system. The special mixer circuit prevents signals from either the T-Mic input or the auxiliary audio input from interfering with each other. Both signals, however, can still be processed by the processing circuits of the BTE and combined in such a way that user is able to perceive both signals at the same time.

BACKGROUND INFORMATION

Cochlear implant (“CI”) systems are known in the art. Such systems allow the profoundly deaf (i.e., those whose middle and/or outer ear is dysfunctional, but whose auditory nerve remains intact) to hear. The sensation of hearing is achieved by directly exciting the auditory nerve with controlled impulses of electrical current, which impulses are generated as a function of perceived audio sounds. The audio sounds are picked up by a microphone carried externally (not implanted) by the deaf person and converted to electrical signals. The electrical signals, in turn, are processed and conditioned by a signal processor to generate a control signal, typically a sequence of pulses of varying width and/or amplitude. The control signal, once generated, is transmitted to an implanted pulse generator of the cochlear implant system. The implanted pulse generator, in response to receipt of the control signal, generates appropriate pulses of electrical current that are applied to one or more electrodes of an electrode array that is inserted into the cochlea of the deaf person. It is this electrical current that directly stimulates the auditory nerve and provides the deaf person (“user”) with the sensation of hearing. Representative cochlear implant systems are described, e.g., in U.S. Pat. Nos. 4,408,608; 4,532,930; 4,947,844; 5,603,726; 6,289,247; 6,754,537; and 7,076,308, incorporated herein by reference.

Most CI systems have a built-in microphone located in the case or housing of the “headpiece” used with the CI system. The headpiece typically includes, in addition to the built-in microphone, an external coil and a magnet. The magnet is used to align the external coil of the headpiece directly over the location where an implanted coil associated with the implanted pulse generator is located. When the external coil and implanted coils are aligned, the external circuits can optimally and efficiently transmit both data and power signals to the implanted circuits of the implanted pulse generator. Disadvantageously, such positioning of the headpiece rarely, if ever, optimally positions the built-in microphone for picking up sound waves.

Because the built-in microphone located in the headpiece does not always sense sound waves in an optimum manner, a popular type of external microphone used with one type of cochlear implant system is a “T-Mic”. A T-Mic is a microphone placed within the concha of the ear near the entrance to the ear canal. Such location is ideal for a microphone because that is the location where sound is naturally collected by the concha of the ear. A T-Mic is described, e.g., in U.S. Pat. Nos. 6,775,389 and 7,020,298, incorporated herein by reference.

The T-Mic is held in its desired position (within the concha of the ear near the entrance of the ear canal) by a boom or stalk that is attached to the ear hook of a behind-the-ear (“BTE”) speech processor. A BTE processor not only includes the signal processing circuitry necessary to receive, amplify and process the signals generated by the microphone in response to sensing audio sounds, but also the circuitry needed to transmit the appropriate control signals to the implanted pulse generator. Additionally, the BTE processor typically carries the batteries needed to power the entire CI system.

In order to keep the BTE processor as light weight and small as possible, it is common to limit the number of accessories that may be attached to it. For example, an exemplary BTE processor employs only a single auxiliary input port. This allows only one accessory to be attached to it at any given time. Thus, while multiple accessories are provided that can be attached to the one auxiliary port of the BTE processor, such as a telecoil, a T-Mic, an FM receiver, and an auxiliary connector (where the auxiliary connector allows an MP3 player, or similar external audio signal source, to be connected directly to the processing circuits of the BTE processor), only one such accessory can be used at any given time.

Many cochlear implant users like to use the T-Mic accessory all the time. When they do so the singular auxiliary input port of the BTE is occupied, thereby preventing users from listening to music or using the hands-free connection feature provided by many cell phones at the same time that the T-Mic is attached to the BTE. Simple splitting of the existing auxiliary port (also referred to herein as the “aux” port) interferes with the T-Mic operation and does not allow simultaneous direct connection of an external audio input and the T-Mic. Therefore, there remains a need for users of the T-Mic to also be able to use an auxiliary port at the same that the T-Mic is being used.

One user of a T-Mic, who does not want to disconnect his T-Mic, but who also wants to be able to have auxiliary sound signals be received as input signals into his BTE processor so that he can hear them, has discovered a way to couple such sounds directly into his T-Mic. Such user acoustically couples a conventional ear bud, attached to his MP3 player, iPod or other auxiliary sound source, directly to his T-Mic. This is done by connecting a first end of a short sound tube over the end of the ear bud and then connecting the other end of the short sound tube over his T-Mic. In this way, sounds broadcast from the ear bud are carried by the short sound tube directly to the T-Mic, where they are electrically sensed and processed by the BTE processor of his CI system.

It is thus seen that there is a need in the art for a CI system having a BTE that allows both a T-Mic and an auxiliary audio input to be connected to the BTE at the same time.

SUMMARY

The systems and methods described herein address the above and other needs by providing a special accessory adapter having two inputs, a T-Mic input and an auxiliary audio input, for use at the same time with a Behind-The-Ear (BTE) processor of a cochlear implant (CI) system. Advantageously, both inputs (the T-Mic input and the auxiliary audio input) are connected to a special mixer circuit integrated into the body of the accessory adapter. The body of the accessory adapter connects to the BTE using the same earhook attachment mechanism used by other accessories of the BTE. The special mixer circuit prevents signals from either the T-Mic input or the auxiliary audio input from interfering with each other. Yet, both signals can still be processed by the processing circuits of the BTE and combined in such a way that user is able to perceive both signals at the same time.

The accessory adapter may be implemented as either a one piece unit, having the T-Mic integrally attached thereto, or as a two-piece unit, where the T-Mic plugs into the adapter body as does an auxiliary audio input jack.

The special mixer circuit advantageously enables a user to use his or her T-Mic while listening to music or other external sources at the same time. Typically when the T-Mic operates, the internal conductance variations in the T-Mic creates a voltage across an external element which powers the microphone (e.g., a resistor connected to a power source) which corresponds to the input sound which feeds into the front-end amplifier of the BTE. Similarly, when an auxiliary audio input signal is plugged into the auxiliary input port, another current flows through the input element which corresponds to the electrical signal coming into the auxiliary input port. When both signals are present at the same time, they are “mixed” together in the input element in a mixing ratio that may be 50/50, or any other portion.

In accordance with one feature of the mixing circuit, most of the current available in the circuit is available for use by the T-Mic. Said another way, the mixing circuit does not consume much current from the Aux port, leaving most of the current to be used by the T-Mic. This allows the T-Mic to be powered by the phantom power available from the auxiliary port of the BTE processor. Due to the minimal current consumption by the auxiliary audio input mixing circuitry, the impact on the T-Mic with no auxiliary audio input signal present is negligible. However, when both the T-Mic and an auxiliary audio input signal are present, the total loudness from both sources is limited to the level that the T-Mic can produce on its own due to the current limitation from the processor through the aux port. Therefore the volume control level may stay the same regardless of whether an auxiliary audio input signal is present.

DETAILED DESCRIPTION

It is known in the art to use a Behind-The-Ear (BTE) processor or device with a Cochlear Implant (CI) system to provide a T-Mic option. A more detailed description of a BTE device may be found in U.S. Pat. No. 5,824,022, incorporated herein by reference. The T-Mic option, when used, places an external microphone in the concha of the ear near the opening of the ear canal. The T-Mic is fully described, e.g., in one or more of U.S. Pat. Nos. 6,748,094; 6,775,389; 7,020,298; 7,142,926; and 7,167,572; which patents are also incorporated herein by reference. It will be understood that a T-Mic may alternatively be referred to by any other name as may serve a particular implementation. Hence, “T-Mic” as used herein refers generally to any external microphone that is not incorporated into a headpiece (e.g., a microphone that may be placed in the concha of the ear near the opening of the ear canal).

A representative BTE device10, used with a CI system, is illustrated inFIG. 1A. The BTE device includes a detachable earhook12, and a battery compartment14. A coaxial connector16provides a mechanism for making both mechanical and electrical attachment of a standard earhook12, as well as other special earhook-type accessories, as described below. That is, the coaxial connector16provides the means for attaching an earhook-type accessory, such as the earhook12, to the main body of the BTE device10. This type of connection is explained in more detail in U.S. Pat. Nos. 6,748,094 and 7,020,298, previously incorporated herein by reference.

FIG. 1Bshows the BTE device10with the earhook12attached, and with the BTE and earhook being positioned on the ear18of a user.

FIG. 1Cdepicts cross-sectional views of various optional accessories that may be attached to the BTE device10. As shown inFIG. 1C, for example, a standard earhook12may be attached to the BTE device10. Such earhook12helps position and hold the BTE device in its desired location behind the ear18(see, e.g.,FIG. 1B). The earhook12attaches to the BTE device10by way of a bore38threaded to receive a standard sized thread. Thus, when attaching the earhook12to the BTE device10, the earhook12, with its threaded bore38, screws on to the coaxial connector16protruding from the body of the BTE device10. The standard earhook12contains no electronic circuits that require an electrical connection with the BTE device10.

FIG. 1Cfurther shows that a special earhook accessory12amay also be attached to the BTE device10. Such accessory12ahas a telecoil18embedded within the earhook. An auxiliary connector40is also included as part of this special earhook12a. The auxiliary connector40both screws onto the coaxial connector16to mechanically mount the special earhook, and provides an electrical connection for leads42running from the telecoil18to the auxiliary connector40.

As further seen inFIG. 1C, another special earhook that may be detachably connected to the BTE10is a T-Mic12b. The T-Mic12bincludes a microphone20mounted near the tip of a boom17that extends from a proximal end of the T-Mic12b. Wires or leads42electrically connect the microphone20to the auxiliary connector40located in the proximal end of the T-Mic12b. The auxiliary connector40, in turn, allows the T-Mic12bto be both mechanically and electrically connected to the coaxial connector16protruding from the BTE device10.

As also seen inFIG. 1C, another special earhook accessory12chas an FM receiver22embedded therein. Wires or leads42electrically connect the FM receiver22to the auxiliary connector40.

Yet another special earhook accessory12dhas a cable24extending to an input plug23. The plug23is adapted to be plugged into the output jack of a suitable audio signal source device, such as an MP3 player, a CD player, a TV, a radio, or an iPod. Wires or leads42embedded within the special earhook12delectrically connect the cable24to an auxiliary connector40. The earhook accessory12dthus allows any audio input source, such as an MP3 player, CD player, or the like, to be connected to the plug23, which connection in turn allows the audio input source to be connected through the earhook12dto the BTE device10.

FIG. 2shows a BTE device10with a T-Mic12battached. The T-Mic12bincludes a proximal earhook portion24, a microphone assembly26, and a stalk28(also referred to as a boom17inFIG. 1C). The stalk28mechanically and electrically connects the microphone assembly26to the earhook portion24. The microphone assembly26includes a microphone25and a soundport30at a distal end of the microphone assembly26. The stalk28may be made from a bendable material that retains its bent position, thereby allowing the microphone assembly to be positioned, through selective bending of the stalk28, at a desired location near the opening of the ear canal. The microphone assembly26is electrically connected through wires embedded in the stalk28, and additional wires21within the BTE device10, to sound processor circuits31contained within the BTE unit10.

Turning next toFIG. 3, there is shown a sectional view of the T-Mic12b, which T-Mic12bis configured to attach to a BTE device10using the same attachment mechanism as is used by other earhook-type accessories. A mating connector40is shown schematically residing in the earhook portion24. Such mating connector40may be any connector suitable to electrically and mechanically connect the earhook portion24to the BTE device10.

The T-Mic12bshown inFIG. 3includes a microphone assembly26located at a distal end of a stalk28. A microphone25resides within the microphone assembly26adjacent a soundport30. At least one wire or cable32is embedded within the stalk28and allows the microphone25to be electrically connected with the mating connector40located at a proximal end of the T-Mic12b.

Combined,FIGS. 1C,2and3highlight the problem solved by the systems and methods described herein. That is, even though a desired external audio source device, such as an MP3 or CD player, may be selectively connected to the BTE through use of the special earhook adapter12dshown inFIG. 1C, they can only do so when the T-Mic accessory12bis disconnected from the BTE device10. This is because there is only one portal gateway into the BTE device, and that is the portal entrance provided through the coaxial connector16. Thus, all auxiliary electrical connections to the input amplifier(s) of the sound processor31must pass through this coaxial connector16. However, because there is only one coaxial connector16provided on the current configuration of the BTE device10, only one audio input source, including the T-Mic, can be connected to the BTE at any given time.

This problem cannot be remedied by simply attaching a “Y” cable or splitter to the single coaxial connector16, with each leg of the “Y” going to a separate auxiliary audio source, e.g., one leg being connected to the T-Mic, and the other leg being connected to an external audio source, such as an MP3 player. This is because of the inherent major impedance mismatches between the T-Mic and the audio input circuitry, on the one hand, and between the external audio source and the audio input circuitry, on the other hand. Connecting the T-Mic and external audio source to the same point through a “Y” connector would thus effectively short out one or both of the T-Mic or external audio sources, thereby greatly degrading or interfering with the performance of those devices.

The systems and methods described herein solve this problem by incorporating a second auxiliary input signal port in a T-Mic adapter accessory, and using a special mixer circuit housed within the body of such T-Mic adapter to combine the input signals from both sources, i.e., from the T-Mic and from the external auxiliary input audio source, so that both can be processed by the BTE amplifier, and other processing circuits within the BTE device, without serious signal degradation or interference occurring between the two signals.

Turning next toFIG. 4, there is shown a one piece T-Mic adapter46that provides simultaneous use of both a T-Mic assembly36and an auxiliary audio input60, which adapter46may also be referred to herein as a “one piece T-Mic/Aux-In adapter”. The one piece T-Mic adapter46shown inFIG. 4includes a housing29, a T-Mic assembly26, and a stalk28. The T-Mic assembly26is connected to one end of the stalk28. The other end of the stalk28is integrally attached to the housing29. The housing29, in addition to having the T-Mic assembly26connected to it by way of the integrally attached stalk, also houses a mixing circuit50, a sound processor interface connector40(also referred to as a “mating connector” in the preceding figures), and an auxiliary input port60.

FIG. 5shows a two piece T-Mic adapter48that provides simultaneous use of both a T-Mic assembly26and an auxiliary audio input port60. The T-Mic adapter48may also be referred to herein as a “two piece T-Mic/Aux-In adapter”. In all material respects the two piece T-Mic/Aux-In adapter48is identical to the one piece T-Mic/Aux-In adapter46described above in connection withFIG. 4, except that the stalk48is detachable from the housing29.

FIG. 6schematically illustrates the mixer circuit50used within the T-Mic/Aux-In Adapter46or48described herein. As seen inFIG. 6, the mixer circuit50includes a port or connection for the T-Mic assembly26and an auxiliary input60. The T-Mic assembly26feeds directly into an amplifier52, via the sound processor interface connector30, through coupling capacitor C1. The T-Mic assembly26receives its operating power through resistor R1, which resistor R1is connected to a suitable power supply voltage or potential54. When thus connected, a bias current i2flows through the T-Mic26. It is this bias current i2that allows the T-Mic26to operate. As the T-Mic26senses audio sounds, those sounds are reflected in variations of the current i2, and thus appear as variations in voltage across resistor R1, which variations in voltage are then amplified by amplifier52and processed by the processing circuits contained within the BTE10.

Further included in the mixing circuit50is auxiliary input circuitry that enables an auxiliary input signal source to be connected to the amplifier52without adversely loading down the T-Mic signal level. As seen inFIG. 6, such auxiliary input circuitry includes a port60into which the auxiliary signal source can be connected. This port is connected to the base of NPN transistor Q1through a coupling capacitor C3. The transistor Q3includes biasing resistor R3connected across its collector and base terminals. The emitter terminal of transistor Q1is connected to the series combination of resistors R4and R2, with one end of resistor R4being connected to the emitter of transistor Q1, and with the other end of R4being connected to one end of resistor R2. The other end of resistor R2is connected to ground. A capacitor C4is connected across resistor R4. Another capacitor C2is connected across resistor R2. These 4 components (R2, R4, C2and C4) allow additional pre-determined frequency shaping of the Auxiliary input when required by the BTE processor. This is performed by changing the component values or eliminating one or both capacitors and one resistor. As a minimum one resistor needs to be connected between the emitter terminal of the NPN transistor to ground of the mixing circuit.

The electronic mixer circuit50, with both a T-Mic26and an auxiliary input signal source60connected thereto, enables its user to use a T-Mic while listening to music or other external sources that are plugged into the Auxiliary Input signal port. As indicated above, when the T-Mic operates, the current i2from the T-Mic develops a voltage across resistor R1corresponding to the input sound which feeds into the amplifier52. A current i1, corresponding to the auxiliary signal source input, also flows through resistor R1creating a corresponding electrical signal. Appropriately selected component values in the circuit, principally resistors R1, R4and R2, allow the mixing ratio to be 50/50 or any other proportion.

One feature of the mixing circuit50is that it will not consume much dc current from the Aux Input port60, leaving most of the current to be used by the T-Mic. This is done by setting resistor R2to a relatively high value. Transistor Q1is basically acting as an AC signal amplifier with minimal current consumption, while maintaining the existing two wire interface from the BTE processor.

The mixing circuitry50and the T-Mic26are powered by the phantom power available from the auxiliary port (sound processor interface40) of the BTE device10. Due to the minimal current consumption of the mixing circuitry50, the impact on the T-Mic current i2when no auxiliary input signal source is connected is negligible. That is, when no auxiliary input signal source is connected, current i1is small and negligible compared to the current i2.

When both a T-Mic26and an auxiliary signal source60are connected to the mixing circuitry50, the current i1is no longer negligible, but neither is it so large that it totally swamps out or overwhelms the T-Mic current i2. Rather, both currents i2and i1assume values that allow both to perform their desired function, i.e., to develop voltage swing variations across resistor R1that represent accurate and non-distorted voltage variations of the actual input signals applied to the auxiliary input signal port60or produced by the T-Mic assembly26. These two signals are thus combined together across resistor R1. The resulting combined signal is then amplified by amplifier52and processed by the BTE circuits, thereby allowing the user to use his or her beloved T-Mic while listening to music or other external sources which are plugged into the auxiliary input signal port.

Another feature of the mixing circuitry50is that the total loudness from both sources (the auxiliary input signal source and the T-Mic source) is limited to the level that the T-Mic26source could produce on its own. This occurs because the circuitry limits the amount of current that can flow from the BTE processor through the auxiliary input signal port. (This limit is basically set by the value of the voltage potential at voltage source54and resistor R1.) Therefore, the volume control level may remain substantially the same regardless of whether one or two signal sources are being applied to the BTE through the mixing circuit50.

FIG. 7illustrates an exemplary method700of connecting two auxiliary devices to a BTE processor having only a single port. WhileFIG. 7illustrates exemplary steps according to one embodiment, other embodiments may omit, add to, reorder, and/or modify any of the steps shown inFIG. 7.

In step702, an adapter housing is provided that has a mating connector adapted to interface with the single port of the BTE processor. Step702may be performed in any of the ways described herein.

In step704, a first connector is provided in the adapter housing that allows a first auxiliary device to be connected to the adapter housing. Step704may be performed in any of the ways described herein.

In step706, a second connector is provided in the adapter housing that allows a second auxiliary device to be connected to the adapter housing. Step704may be performed in any of the ways described herein.

In step708, a combination signal is produced by mixing a first signal received through the first connector from the first auxiliary device with a second signal received through the second connector from the second auxiliary device using mixing circuitry residing within the adapter housing. Step708may be performed in any of the ways described herein.

In step710, the combination signal is input to the single port of the BTE processor. Step710may be performed in any of the ways described herein.

As described above, the systems and methods described herein may provide an adapter for use with a BTE processor of a cochlear implant system that allows both a T-Mic signal and an auxiliary input signal source to be processed by the BTE processor simultaneously. The adapter may include an adapter housing having an auxiliary input signal source port, means for connecting the adapter housing to the BTE processor, means for electrically and mechanically connecting a T-Mic assembly to the adapter housing, the T-Mic assembly configured to output the T-Mic signal, and a mixing circuit adapted to mix the T-Mic signal with an auxiliary input signal applied to the auxiliary input signal port. The mixing circuit may be configured to derive an operating power from the BTE processor and include limiting means for limiting a magnitude of a combined signal resulting from the mixing of the T-Mic signal with the auxiliary input signal to a level that is no greater than the T-Mic signal would be if there were no auxiliary input signal applied to the auxiliary input signal source.

Additionally or alternatively, in a BTE processor used with a cochlear implant system, where the BTE processor has only one port for connecting one auxiliary device to the BTE processor at a time, an adapter that allows two auxiliary devices to be attached to the BTE processor at the same time may include an adapter housing and a mixing circuit within the adapter housing. The adapter housing may have a mating connector adapted to interface with the one port of the BTE processor, a first connection means for allowing a first auxiliary device to be detachably connected to the adapter housing, and a second connection means for allowing a second auxiliary device to be detachably connected to the adapter housing. The mixing circuit may receive operating power from the BTE processor through the one port and be connected in circuit relationship with the first connection means and the second connection means. The mixing circuit is further configured to combine first and second input signals received through the first and second connection means from the first and second auxiliary devices, respectively, to produce a combination signal and to present the combination signal to the mating connector, whereby the combination signal is processed by the BTE processor, whereby the first and second auxiliary devices are connected to the BTE processor at the same time.