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Is Atypical Multisensory Integration in Autism Specific to Socially Contingent Information?

Friday, 3 May 2013: 09:00-13:00
Banquet Hall (Kursaal Centre)
V. A. Bao1,2, L. Mottron3, V. M. Doobay1,2 and A. Bertone1,2,4, (1)School/Applied Child Psychology, Department of Educational and Counselling Psychology, McGill University, Montreal, QC, Canada, (2)Perceptual Neuroscience Laboratory for Autism and Development (PNLab), Montreal, QC, Canada, (3)Service de recherche, Centre d'excellence en Troubles envahissants du développement de l’Université de Montréal (CETEDUM), Montreal, QC, Canada, (4)Centre d'excellence en Troubles envahissants du développement de l’Université de Montréal (CETEDUM), Montreal, QC, Canada
Background: The ability to use multisensory integration (MSI) (i.e., simultaneously integrate information from multiple sensory modalities) allows us to interact adaptively and efficiently with our surroundings by creating a unified and coherent internal representation of the external environment. Both empirical evidence and anecdotal accounts suggest that a decreased ability to integrate information from different senses may partially underlie sensory-related behaviors in autism (Iarocci & McDonald, 2006; Donohue et al 2012). The majority of the evidence supporting altered MSI in autism stems from studies using visual and auditory stimuli that are socio-communicative in nature, such as speech or human faces (Magnée et al 2008; Silverman et al 2010; Smith & Bennetto, 2007). It has been suggested that MSI deficits in autism may be limited to social stimuli, and that this effect may not generalize to low-level sensory information void of social or linguistic characteristics (Bebko et al 2006; Magnee et al 2008; Mongillo et al 2008).

Objectives: To assess MSI in autism using an auditory guided visual illusion task based on sensory information that is non-social in nature (i.e., beeps and flashes) in order to determine whether the purported MSI deficits in autism are generalizable to non-social stimuli.    

Methods: Ten individuals diagnosed with ASD and ten individuals in a typically developing comparison group, matched for full-scale IQ, were asked to complete a computerized visual illusion task (Shams, Kamitani, & Shimojo, 2002) that assessed susceptibility to auditory-guided visual illusions. In this task, participants were required to determine whether they had perceived 1 or 2 flashes (F) while simultaneously hearing 0, 1, or 2 beeps (B). Participants were exposed to four non-illusion trials (i.e., 2F2B, 2F0B, 1F1B, 1F0B) and two illusion trials, whereby a discordant number of flashes and beeps were presented; (a) the fission illusion trial containing 1 flash and 2 beeps (1F2B), and (b) the fusion illusion trial containing 2 flashes and 1 beep (2F1B). Efficient MSI typically results in susceptibility to the illusion, with responses driven by number of beeps (B) presented (i.e., perceiving 2 flashes for the 1F2B fission trials). Susceptibility was measured for each group across illusion and non-illusion trials. 

Results: A mixed-model ANOVA was conducted to determine if group-differences in illusion susceptibility (i.e., decreased accuracy for identifying number of flashes) existed across experimental conditions. Results indicated a significant decrease in accuracy for the illusory compared to the non-illusory conditions for both autism and control groups (i.e., the illusions are present). However, significant group differences were not found for any condition.

Conclusions: Comparable between-group performance on the auditory-guided visual illusion task used in the present study indicates that individuals with autism are able to efficiently integrate low-level, visual and auditory information that is void of social content (i.e., beeps & flashes). This result is consistent with the suggestion that atypical MSI in autism may be specific to situations that call for integrating socially laden information, such as faces and voices.

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