Effects of signal presentation level and word duration on gated word-recognition performance

This study examined the effects of signal presentation level and word duration on time-gated isolated monosyllabic word-recognition performance. Measures of listener confidence, word identification, isolation point (IP), confidence at IP, and acceptance point were obtained from normal-hearing listeners. Subjects were presented with non-time-gated and time-gated speech stimuli at 40 dB SPL (N = 21). The resulting performance measures were compared with previously reported results obtained using an 80-dB SPL presentation level. The speech stimuli consisted of 60-msec time-gated isolated monosyllabic words developed from a prerecorded 50-item list (Auditec, NU-6). Comparisons were drawn between presentation levels, word durations, and time-gated and non-time-gated presentation conditions. Poorer accuracy and longer isolation points were observed at the lower signal presentation level. The findings further indicated that listener confidence at IP was only indirectly influenced by presentation level. Monosyllabic word duration was a significant factor in on-line recognition performance, regardless of presentation level.