International Meeting for Autism Research (London, May 15-17, 2008): REM sleep EEG Beta Activity Correlates With Performance On The Embedded Figure Test in Typically Developing Individuals, But Not In Autistic Persons
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REM sleep EEG Beta Activity Correlates With Performance On The Embedded Figure Test in Typically Developing Individuals, But Not In Autistic Persons

Friday, May 16, 2008
Champagne Terrace/Bordeaux (Novotel London West)
S. Tessier , Sleep Laboratory & Clinic, Hôpital Rivière-des-Prairies, Montréal, QC, Canada
C. Bolduc , Sleep Laboratory & Clinic, Hôpital Rivière-des-Prairies, Montréal, QC, Canada
É. Limoges , Sleep Laboratory & Clinic, Hôpital Rivière-des-Prairies, Montréal, QC, Canada
É. Ménard , Autism Clinic, Hôpital Rivière-des-Prairies, Montréal, QC, Canada
L. Mottron , Autism Clinic, Hôpital Rivière-des-Prairies, Montréal, QC, Canada
R. Godbout , Sleep Laboratory & Clinic, Hôpital Rivière-des-Prairies, Montréal, QC, Canada
Background: Neuropsychological, EEG and brain imaging studies point toward enhanced low-level visual perception in autism, leading to a more local bias and increased performance in low-level visual stimuli than typically developing individuals. Our group has recently reported a decreased contrast between primary and non-primary visual areas for EEG Beta activity during REM sleep in autistic persons in comparison to typically developing individuals.

Objectives: The present study aimed at verifying if EEG Beta activity during REM sleep correlates with performance in the Embedded Figure Test (EFT), a task that relies on visual search and local perception, and consistently performed at a superior level in autism.

Methods: Eight autistic (21.9 ± 4.3 years) and 11 comparison  participants (19.9 ± 4.4 years) were recorded for two consecutive nights. Spectral analysis of REM sleep Beta EEG activity (13.0 to 19.75 Hz) was performed on primary (O1, O2) and non-primary (P7, P8) visual areas. EFT was administered in the morning following night two. Group performance on the EFT task was compared with Mann-Whitney U-tests. The correlation between performance and EEG spectral power was estimated with Spearman’s rho coefficients.

Results: Participants with autism performed better in task completion time than the comparison  group on the EFT task (p<.03). There was a negative correlation between REM sleep EEG Beta activity and time to complete the EFT task in the comparison only (rho = -0.66; p=0.025), not in the autism group (-0.19; p=0.63).

Conclusions: These results suggest that autistic individuals use an atypical visual cortical network in association with enhanced performance in local perceptions tasks. This represents a new support for the hypothesis that REM sleep EEG Beta activity, in addition to reflecting REM sleep control mechanisms, is also an index of visual processing that can differentiate persons with autism from comparison groups.

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