Poster D15, Wednesday, August 21, 2019, 5:15 – 7:00 pm, Restaurant Hall
A Role for the Motor System in Minimally Verbal Individuals with Autism Spectrum Disorder
Maria Mody1,2,3, Seppo P. Ahlfors1,3, Baojuan Li4, Christopher Wreh1, Christopher J. McDougle2,3;1Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, 2Lurie Center for Autism, Massachusetts General Hospital, 3Harvard Medical School, 4School of Biomedical Engineering, Fourth Military Medical University, China
Introduction: Individuals with autism spectrum disorder (ASD) are characterized by deficits in speech and language. The relationship between oral motor and manual motor skills is of particular interest in this population given the notable difficulties in these areas. In a recent study, we found fine motor skills were positively associated with both receptive and expressive language abilities in children with ASD (Mody et al., 2017). We propose to use magnetoencephalography (MEG) to further explore this motor deficit in ASD. Methods: Data was collected using a 306-channel MEG system from 11 minimally-verbal adults with ASD and 11 age- and gender matched neurotypical controls (NT) (mean age: 25 years; right handed) while they performed a self-paced button press task. Head movements were monitored throughout the recording and compensated for in the analysis. MEG data was co-registered with anatomical MRI in each subject. We focused on left hemisphere activation corresponding to dominant (i.e. right) hand button presses. Results: There were no significant differences between the ASD and NT groups in the number of left- or right-hand button presses. Source analysis of the MEG data using minimum norm estimation (MNE) revealed a similar sequence of motor activation in the two groups. However, there was a significant difference in amplitude (p < .008, corrected) between the groups in left superior parietal area in an early time window (20-60 ms) and in the left supplementary motor area (SMA) in a later time window (60-100 ms). Morphometric analysis of the subjects’ MRI data revealed cortical thickness differences in key speech, language and somatomotor areas, along with a reversed pattern of thickness across the hemispheres between the groups. Conclusions: Structural and functional brain differences between the ASD and NT groups provide insight into the results of our previous study. The SMA finding points to motor coordination as a potential basis for the speech deficits in minimally verbal adults with ASD.
Themes: Disorders: Developmental, Language Production
Method: Electrophysiology (MEG/EEG/ECOG)