Supra-normal skills in processing of visuo-auditory prosodic information by cochlear-implanted deaf patients

Area of Science:

• Neuroscience
• Audiology
• Speech Science

Background:

• Cochlear implant (CI) users with acquired deafness rely on multisensory integration (MSI) for speech comprehension.
• Limited understanding exists regarding how CI patients process prosodic speech information.

Purpose of the Study:

• To investigate how CI patients use MSI for paralinguistic prosodic information in multimodal speech.
• To identify visual strategies employed by CI patients during prosodic processing.

Main Methods:

• A psychophysics assessment was used for CI patients and hearing controls (NH) to distinguish questions from statements.
• Eye-tracking recorded oculomotor strategies during the prosodic decision task.
• NH controls were divided into young and age-matched groups.

Main Results:

• CI patients demonstrated significantly supra-normal audiovisual integration for prosodic information compared to NH controls.
• CI patients exhibited a visuo-auditory gain over three times greater than controls.
• CI users employed a distinct oculomotor strategy, fixating more on the mouth region than young NH participants.

Conclusions:

• Prosodic processing is confirmed as multisensory.
• CI patients possess supra-normal MSI skills for integrating visual and auditory prosodic information.
• CI patients develop specific adaptive visual strategies for speech content comprehension.