Binaural dichotic presentation to reduce the effects of spectral masking in moderate bilateral sensorineural hearing loss.
OBJECTIVE
The objective of the study was to evaluate the effectiveness of binaural dichotic presentation using comb filters with complementary magnitude responses, based on fixed bandwidth and auditory critical bandwidth, in improving speech perception by persons with moderate bilateral sensorineural hearing loss, and to assess its effect on localization of the sound source.


METHODS
Listening tests involving consonant recognition and source direction identification were conducted on six normal-hearing subjects under simulated hearing loss and on eleven subjects with moderate bilateral sensorineural loss in quiet.


RESULTS
The tests on normal-hearing subjects showed higher recognition scores and smaller response times for the comb filters based on the auditory critical bandwidth. The tests using these comb filters on the hearing-impaired subjects resulted in an increase of 14%-31% (mean: 22%) in recognition scores and a significant decrease in response times, with no significant effect on the identification of the direction of broadband sound sources.


CONCLUSIONS
The results show that dichotic presentation may be useful for speech processing in binaural hearing aids.
Department of Electrical Engineering, Indian Institute of Technology Bombay, Powai, Maharashtra, India.
Pandurangarao N
PN
Kulkarni
Prem C
PC
Pandey
Dakshayani S
DS
Jangamashetti
D000161:Acoustic Stimulation; D000328:Adult; D001301:Audiometry, Pure-Tone; D001309:Auditory Threshold; D016022:Case-Control Studies; D012048:Correction of Hearing Impairment / Q000523:psychology; D004007:Dichotic Listening Tests; D004867:Equipment Design; D005260:Female; D006310:Hearing Aids; D006312:Hearing Loss, Bilateral / Q000175:diagnosis / Q000523:psychology / Q000534:rehabilitation*; D006319:Hearing Loss, Sensorineural / Q000175:diagnosis / Q000523:psychology / Q000534:rehabilitation*; D006801:Humans; D007194:India; D008297:Male; D008875:Middle Aged; D010470:Perceptual Masking; D019986:Persons with Hearing Disabilities / Q000523:psychology / Q000534:rehabilitation*; D011930:Reaction Time; D021641:Recognition, Psychology; D012720:Severity of Illness Index; D013017:Sound Localization; D013018:Sound Spectrography; D013067:Speech Perception; D013997:Time Factors