Assessing Visual Contributions to the Perception of Speech in Noise.

Investigations of the role of audiovisual integration in speech-in-noise perception have largely focused on the benefits provided by lipreading cues. Nonetheless, audiovisual temporal coherence can offer a complementary advantage in auditory selective attention tasks. We developed an audiovisual speech-in-noise test to assess the benefit of visually-conveyed phonetic information and visual contributions to auditory streaming. The test was a video version of the Children's Coordinate Response Measure with a noun as the second keyword (vCCRMn). The vCCRMn allowed us to measure speech reception thresholds in the presence of two competing talkers under three visual conditions: a full naturalistic video (AV), a video which was interrupted during the target word presentation (Inter), thus, providing no lipreading cues, and a static image of a talker with audio (A). In each case, the video/image could display either the target talker or one of the two competing maskers. We assessed speech reception thresholds in each visual condition in 37 young (≤35 years old) normal-hearing participants. Lipreading ability was independently assessed with the test of adult speechreading (TAS). Results showed that both target-coherent AV and Inter visual conditions offer participants a listening benefit over the static image with audio condition. Target coherent visual information provided the greatest listening advantage in the full audiovisual condition, but a robust advantage was also seen in the interrupted condition, where listeners were unable to lipread the target words. Together, our results are consistent with visual information providing multiple benefits to listening, through lipreading and enhanced auditory streaming.