Abstract
Objective: The aim of the present study was to examine the effect of degree of temporal processing impairment in adult listeners with ANSD on speech perception measures. Study design: Forty-six listeners with ANSD and 30 normal hearing listeners participated in the study. Temporal resolution was measured using the Temporal Modulation Transfer Function (TMTF). Speech identification scores in quiet were measured for bisyllabic words and Speech Reception Threshold in noise (SRTn) was measured for words. Furthermore, consonant identification was measured for 20 VCV stimuli. Results: Listeners with ANSD performed significantly worse than normal hearing listeners in both temporal resolution and speech perception measures. Peak sensitivity and 3dB cut-off frequency were estimated for each individual in both groups from the TMTFs data using an exponential fitting function. The listeners with ANSD were subgrouped into mild, moderate and severe degrees based on peak sensitivity. As the degree of temporal processing impairment increased, speech identification scores reduced and SRTn increased systematically. Similarly, consonant identification decreased with increase in temporal processing impairment. Among phonemic features, manner of articulation was better perceived compared to voice and place of articulation. Conclusion: The high correlation between temporal processing ability and speech perception suggests that temporal processing measures may be a potential tool for assessing the severity of ANSD in adult listeners.