Evaluation of speech processing schemes to improve perception of sensorineural hearing impaired

摘要

Sensorineural hearing impairment occurs due to damage to the transduction mechanism of the inner ear and due to abnormality in the auditory nerve which are responsible for sensing sounds of different pitches. Sensorineural hearing impairment is distinguished by loudness recruitment, reduced frequency selectivity, and increased spectral and temporal masking. Spectral masking results in suppression of two adjacent frequency components by each other. Spectral masking is a source of perceptual confusion in consonantal segments1. Most hearing aids offer facility to vary gain and frequency compensation. These aids cannot resolve the problem of speech perception due to broadening of critical bands. The sensorineural impaired person comes across difficulties while resolving neighbouring frequency components of speech signal2. Splitting speech into two complementary parts on the basis of critical bands and presenting it dichotically helps in lightening these difficulties. The two neighbouring bands, which may mask each other are presented to different ears in dichotic presentation. Receiving speech information binaurally and its perceptual combination have been recognized3. Thus, the scheme should improve the reception of consonantal segment without adversely affecting the reception of other features. Auditory frequency selectivity is illustrated in terms of an equivalent rectangular bandwidth as a function of centre frequency.