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Increasing the Accuracy of Detection of Audio-Visual Integration Differences in Autism Spectrum Disorders

Friday, 3 May 2013: 09:00-13:00
Banquet Hall (Kursaal Centre)
J. M. Bebko1, S. Oczak1, L. N. Hancock1, S. M. Brown1 and J. J. A. Holden2, (1)Psychology, York University, Toronto, ON, Canada, (2)Queen's University, Kingston, ON, Canada

Individuals with autism often have difficulty integrating information across auditory and visual modalities (Bebko et al, 2006; Iarocci & McDonald, 2006). A commonly-used paradigm involves presenting 2 side-by-side visual displays, with an auditory track matched to only one display, while measuring the child’s preferential looking toward the synchronized screen. Using this technique, Bebko et al. (2006) identified a deficit in the processing of speech specific audio-visual intermodal information in children with autism. In many previous studies, preferences are represented by only 60% looking rates, even though chance looking patterns are 50% with two screens. We introduced a modification using a 4-screen display and presented pilot data previously at IMFAR (Hancock et al., 2008). Better discriminability of looking patterns was found, since this methodology lowered chance looking probabilities to 25%, resulting in larger magnitudes of differences from chance. The present study further investigates precision of the 4-screen technique (with eye-tracking), using a larger ASD sample size and including a TD comparison group. 


 To assess the precision of the 4-screen versus 2-screen preferential looking paradigm (PLP). This is done in two stages. First, magnitude of effect (degree of difference from chance) on the 2- and 4-screen tasks for both ASD and TD groups is compared. Second, differences in looking patterns between ASD and TD groups are investigated using the 4-Screen PLP and eye-tracking data with linguistic and non-linguistic stimuli, and these results are compared with previous differences on 2-screen studies.


23 children with ASD and 23 TD children between the ages of 3 and 12 years were tested. The 4-Screen PLP involved displaying four identical videos, offset in time, with an auditory track synchronous to only one of the videos. Videos contained either linguistic (L, person telling a story) or non-linguistic (NL, hand playing a piano) stimuli. Preferential looking is assessed from differences in total time looking at each screen.


Initial analyses indicate that the 4-screen variant produces more discriminable magnitudes of effect compared to chance: approximately 40% greater looking time at the preferred video over chance, vs. the 2-screen paradigm (approximately 10% greater than chance). Corrected for their relative chance levels (.25 vs .50), this is an 8-fold increase in precision in the ability to detect preference, which represents a major advance in sensitivity for the paradigm .  Two other results from previous two-screen studies were also preserved: First, for non-linguistic stimuli, both groups showed similar proportions of preferential looking to synchronous non-linguistic videos. In addition, we replicated the finding of an apparent speech-specific deficit in intermodal processing (IMP). Further analyses are ongoing.


These findings demonstrate the strongly increased sensitivity of using a 4-screen over a 2-screen paradigm in detecting differences in preferential looking in ASD and TD children with audio-visual information. Often subtle differences occur, and the ability to detect them will enable a clearer understanding of variables contributing to the language difficulties in ASDs. The corroboration of our previous findings of an apparent speech-specific IMP difficulty in ASDs lends additional confidence to the paradigm.

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