The intelligibility of glimpsed speech: Effect of competing amplitude modulation

Abstract

The present study investigated how amplitude modulation of an interrupted noise influences the intelligibility of glimpsed speech. Prior studies have demonstrated that amplitude modulation can aid speech intelligibility when speech is periodically interrupted. This study used a competing talker to define high-intensity and low-intensity speech glimpses that were used to interrupt the target speech. These interrupted intervals were filled by one of five different types of amplitude modulated noise; each noise was presented at two different presentation levels. Silent interruption was also examined. This resulted in 22 different experimental conditions. The results indicated effects of glimpsed speech level, noise modulation, and noise level. In agreement with previous studies using periodic interruption, significant benefit was obtained when the noise was amplitude modulated by the missing speech segment, but only when the modulation came from high-intensity speech segments. In contrast, amplitude modulation of the noise by previous high-intensity, preserved portions of the target sentence produced lower intelligibility scores. Additionally, speech recognition with noise amplitude modulated by a competing talker interacted with the glimpsed speech level. These results indicate that amplitude modulation of an interrupted noise can have different effects on sentence recognition, dependent on the informational content of the modulation.