Adaptive Cancellation System For Implantable Hearing Instruments

A method for use with an implantable hearing instrument, comprising:

• providing first and second adaptive filters operative to filter the output of a motion sensor to substantially match the output of an implantable microphone, wherein said first and second filters are identical and wherein filter coefficients of each said adaptive filter are dependent upon a variable associated with operating conditions of said implantable hearing instrument;
• receiving outputs from an implantable microphone and a motion sensor;
• generating an estimate of said variable;
• first filtering said motion output using said first adaptive filter to produce a first filtered motion output, wherein said first adaptive filter utilizes filter coefficients generated based on said estimate of said variable;
• second filtering said motion output using said second adaptive filter to produce a second filtered motion output, wherein said second adaptive filter utilizes filter coefficients that are a predetermined value different than said estimate of said variable;
• removing said first and second filtered outputs from said output of said implantable microphone to generate first and second cancelled signals;
• and
• adjusting said estimate of said variable based on a comparison of said first and second cancelled signals.

A system for use with an implantable hearing instrument, comprising:

• an implantable microphone operative to subcutaneously receive sound and generate a microphone output signal;
• a microphone operative to receive sound and generate a microphone output, said microphone being adapted for subcutaneous positioning;
• a motion sensor for generating a motion signal indicative of motion of said microphone;
• a first adaptive filter operative to filter the output of said motion sensor to correspond with the output of said implantable microphone to motion, wherein filter coefficients of said first adaptive filter are dependent upon a variable associated with operating conditions of said implantable hearing instrument;
• a first summation device for combining said microphone output and said filtered motion signal to generate a first cancelled signal;
• a second adaptive filter operative to filter the output of said motion sensor to substantially model the output of said implantable microphone to motion, wherein said first and second filters are identical and wherein filter coefficients of each said adaptive filter are dependent upon a variable associated with operating conditions of said implantable hearing instrument;
• a second digital filter adapted to receive said motion sensor and generate a feedback signal that models a response of said microphone to operation of said implantable auditory stimulation device;
• a second summation device for combining said microphone output and said feedback signal to generate a second compensated microphone signal;
• and
• a controller operative to select at least a portion of one of said first and second compensated microphone signals for at least one frequency band and provide such selected portions to a signal processor for use in generating drive signals for actuating said implantable auditory stimulation device;
• a motion sensor operative to generate a motion sensor output indicative of motion;
• a first adaptive filter for modeling said motion sensor output to said microphone output, wherein coefficients of said adaptive filter are dependent upon a variable associated with operating conditions of said implantable hearing instrument.