Effect Of Age And Hearing Loss On Sentence Perception In Noise Using Temporal Envelope And Temporal Fine Structure Cues

Purpose: The perception of speech is affected by many physical, physiological and pathological factors related to the stimuli and the listener. Researchers have addressed the effect of each of these factors independently on the perception of speech. In everyday situations, these factors do not occur in isolation but they may occur simultaneously and affect the overall perception of speech. The information on the extent to which each of these factors affect the speech perception is seldom being investigated.Methods: The present study explored the role of temporal envelope and temporal fine structures in the perception of sentences in noise by normal hearing young & older adults; and young & older adults with hearing loss. The envelope and fine structures of the sentences were extracted based on Hilbert transformation using Matlab software. The effect of noise was estimated by processing the sentences in quiet and at 0 dB and -5 dB SNR. The sentences were also filtered using 4, 8, 16 and 32 frequency channels to assess the role of frequency filtering on speech perception.Results: The envelope was more important for speech perception in both quiet and noise. The perception of speech was inversely proportional to age, hearing loss and noise levels, whereas it was directly proportional to the number of frequency channels.Conclusion: These findings indicate that the temporal envelope is important for speech perception in noise. The research findings may help in designing new signal processing strategies for hearing aids and cochlear implants based on the envelope cues.