Psychoacoustic Measures and Speech Perception of Compressed Rate of Sentences in Noise in Individuals with Congenital and Acquired Blindness

ABSTRACT

Without visual information, blind speakers rely solely on the auditory signal to recover phonological information. We wanted to measure the psychoacoustic measures and perception of compressed speech in noise in individuals with congenital and acquired blindness and correlate the temporal resolution and frequency resolution ability with individuals with normal sight.METHODSThe clinical group (age range-12-20 years) contains two subgroups- congenital blindness and acquired blindness, with normal hearing each containing 15 participants. 15 participants with normal vision were selected as controls. To measure the temporal processing ability each participant was asked to perform Gap detection test. Similarly, difference limen frequency was estimated from pitch discrimination of pure tones. The task for speech perception of compressed sentences was done at different rate of compression at different SNRs.RESULTSResults indicated that there was significant difference in gap detection threshold between congenital blinds and normal sighted participants as well as between acquired blinds and normal sighted participants. There was significant difference in frequency discrimination scores between blind listeners and normal sighted participants. The sentence perception score was better in those participants who have congenital blindness than acquired blindness followed by normal sighted participants in each experimental condition.CONCLUSIONSFrom the investigation, it can be concluded that the psychoacoustic measures are better in individuals with blindness than individuals with normal sight. speech perception deteriorates with an increase in noise in both normal sighted individuals and individuals with blindness. Effect of noise is more for individuals with normal sight than blind listeners.