Bilateral hearing assistance system and a method of fitting a bilateral hearing assistance system
The application relates to a bilateral hearing assistance system comprising first and second hearing assistance devices a processing unit, which in a NORMAL mode of operation processes an input audio signal based on configurable processing parameters and provides a processed electric stimulation signal. The system further includes one or more stimulation units for—in a TEST mode delivers first and second electric TEST stimulation signals to output units of said first and second devices respectively. The application further relates to a method of fitting a bilateral hearing assistance system to a particular user. The disclosure provides a measure allowing an improved fitting of bilaterally implanted Cochlear Implant users. The system further includes an evaluation unit configured to analyze the recorded physiological response of the user and to provide an objective measure of the user's perception of said TEST stimulation signals.
1. A bilateral hearing assistance system comprising a control unit and first and second hearing assistance devices, each of the first and second hearing assistance devices
being adapted for being located at or in an ear of the user or to be partially or fully implanted in the head at an ear of the user, and
comprising an output unit adapted to present a stimulation signal to said user in a form allowing it to be perceived by the user as an auditory signal,
the bilateral hearing assistance system further comprising
one or more stimulation units for, in a TEST mode of operation of the hearing assistance system, delivering first and second electric TEST stimulation signals to said output units of said first and second hearing assistance devices, respectively;
a recording unit configured to record the user's physiological response to said first and/or second electric TEST stimulation signals; and
an evaluation unit being configured to analyze the recorded physiological response of the user and to provide an objective measure of the user's perception of said TEST stimulation signals,
wherein the first and second TEST stimuli comprise abrupt interaural phase changes (IPCs) imposed on amplitude modulated signals and wherein the recording of the user's physiological response comprises recording the Frequency Following Response to said interaural phase changes.
2. A bilateral hearing assistance system according to claim 1 wherein said control unit is configured to control said first and second electric stimulation signals.
3. A bilateral hearing assistance system according to claim 1 comprising a processing unit, which in a NORMAL mode of operation is adapted to process an input audio signal based on configurable processing parameters and to provide a processed electric stimulation signal to respective output units of the first and second hearing assistance devices.
4. A bilateral hearing assistance system according to claim 1 wherein the control unit is adapted to modify said first and second electric TEST stimulation signals based on said objective measure of the user's perception of said stimulation signals.
5. A bilateral hearing assistance system according to claim 3 configured to modify said configurable processing parameters of the first and/or second hearing assistance devices based on said objective measure of the user's perception of said TEST stimulation signals.
6. A bilateral hearing assistance system according to claim 1 wherein the first hearing assistance device comprises
a first implanted part adapted for being implanted in an ipsi-lateral side of the user's head, the implanted part comprising the output unit of the first hearing assistance device, and wherein said output unit comprises a first multi-channel electrode array adapted for being located in proximity of neurons of the auditory system of the user; and
a first electrode control unit configured to provide that a specific electrode in the first multi-channel electrode array is stimulated by said first electric TEST stimulation signal.
7. A bilateral hearing assistance system according to claim 6 wherein the second hearing assistance device comprises
a second implanted part adapted for being implanted in a contra-lateral side of the user's head, the implanted part comprising the output unit of the second hearing assistance device, and wherein said output unit comprises a second multi-channel electrode array adapted for being located in proximity of neurons of the auditory system of the user; and
a second electrode control unit configured to provide that a specific electrode in the first multi-channel electrode array is stimulated by said second electric TEST stimulation signal.
8. A bilateral hearing assistance system according to claim 6 wherein the second hearing assistance device comprises
an ear piece adapted for being located in or at an ear at a contra-lateral side of the user's head, the ear piece comprising the output unit of the second hearing assistance device, said output unit being adapted for converting said second electric TEST stimulation signal to an output sound and playing said output sound into the ear of the user.
9. A method of fitting a bilateral hearing assistance system to a particular user, the bilateral hearing assistance system comprising first and second hearing assistance devices, each being adapted for being located at or in an ear of the user or to be partially or fully implanted in the head at an ear of the user, each of the first and second hearing assistance devices being configured to allow electrical, mechanical or acoustic stimulation of the auditory system of the user,
the method comprising
generating first TEST stimuli to the auditory system at an ipsi-lateral side of the user's head;
generating second TEST stimuli to the auditory system at a contra-lateral side of the user's head;
recording the user's physiological response to either ipsi-lateral, contra-lateral, or bilateral stimulation;
evaluating the recorded physiological responses of the user to extract information about the current fitting of the first and second hearing assistance devices,
wherein the first and second TEST stimuli comprise abrupt interaural phase changes (IPCs) imposed on amplitude modulated signals and where the recording of the user's physiological response comprises recording the Frequency Following Response to said interaural phase changes.
10. A method according to claim 9 comprising adapting processing parameters of the first and second hearing assistance devices based on the extracted information about the current fitting of the first and second hearing assistance devices.
11. A method according to claim 9 wherein the first and second hearing assistance devices each comprises a cochlear implant hearing assistance device.
12. A method according to claim 9 wherein first and second TEST stimuli each comprise a train of pulses.
13. A method according to claim 9 wherein the strength or the phase or both strength and phase of a steady-state auditory response produced by the first and second TEST stimuli is used to assess the optimality of the binaural fitting parameters.
14. A method according to claim 9 wherein the phase of the carrier signal of the first and second TEST stimuli are configured to produce discrete IPCs at minimums in the modulation cycle.
15. A bilateral hearing assistance system according to claim 2 comprising a processing unit, which in a NORMAL mode of operation is adapted to process an input audio signal based on configurable processing parameters and to provide a processed electric stimulation signal to respective output units of the first and second hearing assistance devices.
16. A bilateral hearing assistance system according to claim 2 wherein the control unit is adapted to modify said first and second electric TEST stimulation signals based on said objective measure of the user's perception of said stimulation signals.
17. A bilateral hearing assistance system according to claim 3 wherein the control unit is adapted to modify said first and second electric TEST stimulation signals based on said objective measure of the user's perception of said stimulation signals.
18. A bilateral hearing assistance system according to claim 4 configured to modify said configurable processing parameters of the first and/or second hearing assistance devices based on said objective measure of the user's perception of said TEST stimulation signals.
19. A bilateral hearing assistance system according to claim 2 wherein the first hearing assistance device comprises
a first implanted part adapted for being implanted in an ipsi-lateral side of the user's head, the implanted part comprising the output unit of the first hearing assistance device, and wherein said output unit comprises a first multi-channel electrode array adapted for being located in proximity of neurons of the auditory system of the user; and
a first electrode control unit configured to provide that a specific electrode in the first multi-channel electrode array is stimulated by said first electric TEST stimulation signal.