Implantable cochlear system with integrated components and lead characterization
Cochlear implant systems can include a cochlear electrode, a stimulator in electrical communication with the cochlear electrode, a sensor configured to receive a stimulus signal and generate an input signal based on the received stimulus signal, and a signal processor in communication with the stimulator and the sensor. The signal processor can include an analog filtering stage configured to generate an analog filtered signal from a received input signal and a digital filtering stage configured to generate a digitally filtered signal from the analog filtered signal. The analog filtering stage and digital filtering stage can be used to normalize the frequency response of the digitally filtered signal with respect to the stimulus signal.
1. A method of compensating for variability in a middle ear sensor comprising:
applying a plurality of stimulus signals to a middle ear sensor, the plurality of stimulus signals having known frequency content and including a corresponding plurality of frequencies or frequency ranges;
for each of the plurality of stimulus signals:
receiving the stimulus signal via a middle ear sensor,
generating, with the middle ear sensor, an input signal based on the stimulus signal;
applying an analog filter to the generated input signal to generate an analog filtered signal;
applying a digital filter to the generated analog filtered signal to generate a digitally filtered signal corresponding to the stimulus signal; and
measuring a frequency response of the digitally filtered signal with respect to the corresponding stimulus signal, the measuring the frequency response of the digitally filtered signal with respect to the corresponding stimulus signal comprising determining a ratio of a magnitude of the digitally filtered signal to a magnitude of the corresponding stimulus signal; and
adjusting the digital filter to normalize the frequency response of the digitally filtered signals with respect to the stimulus signals across the plurality of frequencies or frequency ranges.
2. The method of claim 1 , wherein the applying the plurality of stimulus signals comprises applying stimulus signals having frequencies ranging between 100 Hz and 10 kHz.
3. The method of claim 1 , wherein adjusting the digital filter to normalize the frequency response of the digitally filtered signals with respect to the stimulus signals comprises adjusting the digital filter so that the determined ratio is approximately equal for each of the plurality of frequencies or frequency ranges.
4. The method of claim 1 , wherein applying the analog filter to the generated input signals comprises applying a plurality of analog filters and/or analog amplifiers.
5. The method of claim 4 , further comprising adjusting the analog filter to normalize the frequency response of the digitally filtered signals with respect to the stimulus signals.
6. The method of claim 1 , further comprising applying a transfer function to the digitally filtered signals to generate stimulation signals.
7. The method of claim 6 , further comprising adjusting the transfer function using an external wireless communication device via a wireless communication protocol.
8. The method of claim 7 , wherein adjusting the transfer function comprises using the external wireless communication device to collect auditory data representative of a surrounding environment.
9. The method of claim 8 , further comprising:
identifying background noise in the collected auditory data of the external wireless communication device; and
updating the transfer function to reduce a contribution of the identified background noise in the stimulus signals.
10. The method of claim 9 , wherein updating the transfer function to reduce the contribution of the identified background noise comprises emphasizing signals having frequency content between approximately 200 Hz and 20 kHz.
11. The method of claim 10 , wherein updating the transfer function to reduce the contribution of the identified background noise comprises emphasizing signals having frequency content between approximately 300 Hz and 8 kHz.
12. The method of claim 9 , wherein updating the transfer function to reduce a contribution of identified background noise comprises emphasizing frequencies associated with human speech.
13. The method of claim 6 , further comprising:
receiving information from a fitting hub regarding a sound output from a speaker of the fitting hub;
receiving input signals generated via the middle ear sensor in response to the sound output from the speaker; and
analyzing the information received from the fitting hub regarding the sound output from the speaker and the input signals from the middle ear sensor in response to the sound output from the speaker to determine a relationship between the sound output from the speaker of the fitting hub and the resulting input signals generated via the middle ear sensor in response to the sound output from the speaker.
14. The method of claim 13 , further comprising updating the transfer function in response to the determined relationship.
15. The method of claim 6 , further comprising providing an electrical signal to a cochlear electrode based on the stimulation signals.
16. The method of claim 15 , wherein
applying the transfer function to the digitally filtered signals is performed by a signal processor;
providing the electrical signal to the cochlear electrode is performed by a stimulator; and
the signal processor and the stimulator are located in a single housing.