Envelope-based inter-aural time difference localization training to improve speech-in-noise perception in the elderly.

Many elderly individuals complain of difficulty in understanding speech in noise despite having normal hearing thresholds. According to previous studies, auditory training leads to improvement in speech-in-noise perception, but these studies did not consider the etiology, so their results cannot be generalized. The present study aimed at investigating the effectiveness of envelopebased interaural time difference (ITD ENV) localization training on improving ITD threshold and speech-in-noise perception. Thirty-two elderly males aged 55 to 65 years with clinically diagnosed normal hearing at 250-2000 Hertz, who suffered from speech-in-noise perception difficulty participated in this study. These individuals were randomly divided into training and control groups: 16 elderlies in the experimental group received envelope-based interaural time difference localization training in 9 sessions, but 16 matched elderlies in the control group did not receive any training. The ITD ENV threshold and spatial word recognition score (WRS) in noise were analyzed before and after the localization training. Findings demonstrated that following the training program, the interaural time difference envelope threshold and spatial word recognition score (WRS) in noise were improved significantly in the experimental group (p≤ 0.001). Moreover, a significant difference was detected in interaural time difference envelope threshold and spatial word recognition score (WRS) in noise (p≤ 0.001) before and after the training in the experimental group. The results of the present study revealed the effectiveness of envelope- based interaural time difference localization training in localization ability and speech in noise perception in the elderlies with normal hearing up to 2000 Hz who suffered from speech-in-noise perception difficulty.