Individuals with autism frequently show difficulty integrating information from multiple sources into coherent representations of the world around them. This perceptual deficit may be especially harmful during early development, when much of what is learned about language and communication involves integration of auditory and visual information from other humans'speech and behaviors. A crucial aspect of multisensory integration in typical individuals is the ability to perceive and utilize temporal synchrony cues to locate and identify multisensory objects. While previous work strongly suggests that temporal synchrony detection is altered in individuals with autism, the impact of such a deficit on multisensory integration remains to be studied. This Study will investigate the relationship between temporal synchrony detection and multisensory integration in children with autism and well-matched controls by measuring the contribution of temporal synchrony detection to the localization, identification, and neural processing of multisensory speech and non-social objects. Localization and identification will be measured with a time-window-of-integration paradigm, which involves altering the synchrony of auditory and visual displays and testing whether participants are able to utilize the asynchronous display to enhance perception. Neural processing of temporal synchrony will be investigated by measuring changes in event related potentials (ERP), one of the most temporally sensitive measures of neural activity, during small changes in asynchrony. This project will test the hypothesis that individuals with autism are less sensitive to temporal asynchrony in basic multisensory integration tasks compared to controls, and that this group difference will be evident with both speech and nonsocial (i.e., object) stimuli. This project will further test this hypothesis of atypical temporal synchrony detection during an ERP task. The temporal resolution afforded by ERP methods as well as the decreased attentional requirements of the ERP paradigm (i.e.. Mismatch Negativity), will provide the most sensitive test of basic neural deficits in temporal processing in autism. The proposed studies will test the general hypothesis that individuals with autism show problems integrating visual and auditory information due to deficits in processing temporal cues. This investigation of the nature of temporal processing deficits will provide clues to the etiology of communication deficits in autism, and will indicate the degree to which temporal processing and multisensory integration ought to be foci of early intervention programs.
| Smith, Elizabeth; Zhang, Shouling; Bennetto, Loisa (2017) Temporal synchrony and audiovisual integration of speech and object stimuli in autism. Res Autism Spectr Disord 39:11-19 |
