Deficient saccadic inhibition in Asperger's disorder and the social-emotional processing disorder.
BACKGROUND
Both Asperger's disorder and the social-emotional processing disorder (SEPD), a form of non-verbal learning disability, are associated with executive function deficits. SEPD has been shown to be associated with deficient saccadic inhibition.


OBJECTIVE
To study two executive functions in Asperger's disorder and SEPD, inhibition and task switching, using a single saccadic paradigm.


METHODS
22 control subjects and 27 subjects with developmental social processing disorders-SEPD, Asperger's disorder, or both syndromes-performed random sequences of prosaccades and antisaccades. This design resulted in four trial types, prosaccades and antisaccades, that were either repeated or switched. The design allowed the performance costs of inhibition and task switching to be isolated.


RESULTS
Subjects with both Asperger's disorder and SEPD showed deficient inhibition, as indicated by increased antisaccade errors and a disproportionate increase in latency for antisaccades relative to prosaccades. In contrast, task switching error and latency costs were normal and unrelated to the costs of inhibition.


CONCLUSIONS
This study replicates the finding of deficient saccadic inhibition in SEPD, extends it to Asperger's disorder, and implicates prefrontal cortex dysfunction in these syndromes. The finding of intact task switching shows that executive function deficits in Asperger's disorder and SEPD are selective and suggests that inhibition and task switching are mediated by distinct neural networks.
Manoach
D S
DS
Department of Psychiatry and the Athinoula A Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02129, USA. dara@nmr.mgh.harvard.edu
Lindgren
K A
KA
Barton
J J S
JJ
D000328:Adult; D000342:Affective Symptoms / Q000209:etiology* / Q000523:psychology; D020817:Asperger Syndrome / Q000150:complications*; D005260:Female; D006801:Humans; D008297:Male; D008606:Mental Processes; D008875:Middle Aged; D009415:Nerve Net; D015835:Ocular Motility Disorders / Q000209:etiology; D012438:Saccades; D012919:Social Behavior; D013647:Task Performance and Analysis