Dichotic presentation of speech signal with critical band filtering for improving speech perception

The reduction in the frequency resolving capacity of the auditory system due to the spread of masking of frequency components by neighboring components degrades speech perception in cases of sensorineural hearing impairment. We have carried out an experimental evaluation of splitting speech into two signals by using a bank of critical band filters, in order to reduce the effect of spectral masking in the cochlea. The dichotically presented signals are perceptually integrated in the auditory cortex. Listening tests were carried out with vowel-consonant-vowel and consonant-vowel syllables for twelve English consonants on five normal hearing subjects with simulation of sensorineural impairment done by adding white masking noise to the speech signal at various SNRs. Significant improvements in the recognition score were obtained under adverse listening conditions. An improvement in the reception of speech feature of voicing, place, and manner was observed in information transmission analysis.