The Relationship between Temporal Integration and Temporal Envelope Perception in Noise by Males with Mild Sensorineural Hearing Loss.

Abstract

A surge of literature indicated that temporal integration and temporal envelope perception contribute largely to the perception of speech. A review of literature showed that the perception of speech with temporal integration and temporal envelope perception in noise might be affected due to sensorineural hearing loss but to a varying degree. Because the temporal integration and temporal envelope share similar physiological processing at the cochlear level, the present study was aimed to identify the relationship between temporal integration and temporal envelope perception in noise by individuals with mild sensorineural hearing loss. Thirty adult males with mild sensorineural hearing loss and thirty age- and gender-matched normal-hearing individuals volunteered for being the participants of the study. The temporal integration was measured using synthetic consonant-vowel-consonant syllables, varied for onset, offset, and onset-offset of second and third formant frequencies of the vowel following and preceding consonants in six equal steps, thus forming a six-step onset, offset, and onset-offset continuum, each. The duration of the transition was kept short (40 ms) in one set of continua and long (80 ms) in another. Temporal integration scores were calculated as the differences in the identification of the categorical boundary between short- and long-transition continua. Temporal envelope perception was measured using sentences processed in quiet, 0 dB, and -5 dB signal-to-noise ratios at 4, 8, 16, and 32 contemporary frequency channels, and the temporal envelope was extracted for each sentence using the Hilbert transformation. A significant effect of hearing loss was observed on temporal integration, but not on temporal envelope perception. However, when the temporal integration abilities were controlled, the variable effect of hearing loss on temporal envelope perception was noted. It was important to measure the temporal integration to accurately account for the envelope perception by individuals with normal hearing and those with hearing loss.