Visual Gestures of the Head and Eyebrows Support Prosody Perception for Individuals with Cochlear Implants.

Visual gestures, especially head movements and eyebrow raises, are time-locked to acoustic cues during the expression of spoken prosody. The present study examined the role these visual cues play in prosody perception, particularly for individuals with cochlear implants (CIs), who often experience challenges understanding prosody due to reduced access to pitch cues. A vocal mimicry paradigm was used to obtain granular, objective measures of prosody perception through acoustic analysis of mimicked sentences. Stimuli consisted of audio-visual recordings from one talker that captured naturally occurring variability in the expression of auditory and visual cues to word focus. Participants mimicked these natural recordings, as well as prosody-transplanted stimuli that allowed us to isolate the influence of auditory or visual prosody cues while holding the other modality at a neutral level (broad focus). Participants converted visual prosody cues into acoustic correlates of prosody in their mimicry, repeating acoustically unfocused words with higher F0 and intensity when those words were paired with video containing head and eyebrow gestures. This visual influence was stronger for participants with CIs than an age-matched group of typical-hearing listeners. CI participants who were less successful at acoustic mimicry tended to be more influenced by visual cues. These results indicate that CI listeners compensate for degraded auditory cues by integrating visual gestures into their perception of spoken prosody, potentially highlighting new targets for multisensory counseling or training.