Autism Consortitum - 2nd Scientific Retreat (2007)

ABSTRACT

Protocol:
Participants were 25 adolescents with autism and 25 TD controls, matched for age, sex, verbal and non-verbal IQ. Our stimuli consisted of 12 video clips taken from a longer narrative about baking dessert. Each clip contained a complete sentence or phrase and was 3 seconds long (+-200ms). We then "slipped" each clip's video and audio tracks out of phase, with the video preceding the audio, by 4, 6, 8, 10, 12, and 14 frames, thereby creating 7 versions of each clip (including one synchronous presentation) for a total of 84 stimuli. The slip rates were selected to allow for performance above and below the reliable asynchrony detection threshold of 8 to 10 frames for a typical adolescent population as determine by a pilot study. Participants were asked to view the clips, which were presented in one of 2 randomized, counterbalanced sequences with a 3 second interstimulus interval to allow for adequate response time, and determine whether each clip was "in-sync" or not. Data analysis: Our data show an expected main effect for slip rate (F(5,260)=397.6, p<.001), with higher slip rates resulting in more accurate asynchrony detection, but no main effect for group, or group by slip rate interaction.

Conclusion:
Our data indicate that individuals with ASD can successfully attend to both the visual and auditory components of language and detect onset asynchrony between the two modalities as successfully as their TD peers. The difference between our results and those obtained for participants with ASD in McGurk paradigms may indicate that meaningful linguistic context provides this population with a better basis for auditory/visual integration than single non-word syllables. Overall we conclude that adolescents with ASD are as able as their TD peers to integrate rapidly presented visual and auditory speech information during the presentation of natural dynamic language.