Behavioral and Electrophysiological Correlates of Auditory-Visual Integration in Persons with Stuttering

Abstract

Over the years, there is growing evidence that adults who stutter (AWS) have compromised central auditory processing. A few studies have also indicated that AWS have faulty visual processing. These results in combination hints possible deficits in AV perception in AWS. Therefore, the present study aimed at investigating the behavioural and electrophysiological correlates of AV perception in thirty AWS in comparison with age and gender-matched thirty adults who do not stutter (AWNS). The behavioural identification scores and reaction times were measured during identification of AV consonant-vowel syllables in congruent, incongruent (McGurk and non-McGurk variants), audio-only and video-only conditions. The temporal window of AV integration for McGurk incongruent syllables was also measured. Furthermore, the Long Latency Responses (LLRs) were recorded in all the four conditions. The results of behavioural identification scores and reaction time revealed no significant difference between the groups. Although the polynomial fit revealed wider temporal integration window in AWS compared to AWNS, there was no significant difference in identification scores at each asynchronous condition between the groups. The spatiotemporal analyses, microstates and source estimation of LLR and AV interaction waveforms revealed significant differences between the groups during both early and late processing stages. Interestingly, these differences were present only for McGurk but not for non-McGurk incongruent syllable.