Improvement in speech intelligibility in noise employing an adaptive filter with normal and hearing-impaired subjects.

It is well known that communication in noisy environments with reverberation present is a difficult problem to solve, particularly for the hearing-impaired listener. Two-microphone noise cancelling using an LMS adaptive filter in real time was used to process speech recorded in the presence of speech-spectrum noise at six different signal-to-noise ratios, -8, -4, 0, 4, 8, and 12 dB. Twelve normal-hearing and 11 sensorineural hearing-impaired subjects were tested. Results indicated mean improvement of 37.34 percent for the 12 normal-hearing subjects and 38.3 percent for 5 of the sensorineural hearing-impaired subjects. Individual data for the 5 remaining hearing-impaired subjects revealed severe speech intelligibility deficits when noise and reverberation contaminated the speech signal. It is proposed that rehabilitative audiological assessments include evaluation of an individual's ability to cope with reverberation and noise.