AUDIOVISUAL PERCEPTION OF COMPRESSED SPEECH BY PROFOUNDLY HEARING-IMPAIRED SUBJECTS

For many people with profound hearing loss conventional hearing aids g ive only little support in speechreading. This study aims at optimizin g the presentation of speech signals in the severely reduced dynamic r ange of the profoundly hearing impaired by means of multichannel compr ession and multichannel amplification, The speech signal in each of si x 1-octave channels (125-4000 Hz) was compressed instantaneously, usin g compression ratios of 1, 2, 3, or 5, and a compression threshold of 35 dB below peak level. A total of eight conditions were composed in w hich the compression ratio varied per channel. Sentences were presente d audio-visually to 16 profoundly hearing-impaired subjects and syllab le intelligibility was measured, Results show that all auditory signal s are valuable supplements to speechreading. No clear overall preferen ce is found for any of the compression conditions, but relatively high compression ratios (>3-5) have a significantly detrimental effect, In spection of the individual results reveals that compression may be ben eficial for one subject.