The semantic Simon effect in Tourette’s syndrome and obsessive-compulsive disorder

• Published in: Brain and cognition 2006-08, Vol.61 (3), p.225-234
• Main Authors: Rankins, D., Bradshaw, J.L., Georgiou-Karistianis, N.
• Format: Article
• Language: English
• Subjects: Adult and adolescent clinical studies; Anxiety disorders. Neuroses; Biological and medical sciences; Clinical Diagnosis; Cognition Disorders - diagnosis; Cognition Disorders - epidemiology; Cognitive Processes; Comparative Analysis; Degenerative and inherited degenerative diseases of the nervous system. Leukodystrophies. Prion diseases; Female; Humans; Inhibition; Inhibition (Psychology); Male; Medical sciences; Middle Aged; Neurological Impairments; Neurology; Neuropsychological Tests; Neuropsychology; Obsessive-Compulsive Disorder - epidemiology; Obsessive-compulsive disorders; OCD; Organic mental disorders. Neuropsychology; Patients; Psychology. Psychoanalysis. Psychiatry; Psychopathology. Psychiatry; Reaction Time; Semantics; Severity of Illness Index; Simon effect; Stimuli; Symptoms (Individual Disorders); Tourette Syndrome - epidemiology
• ISSN: 0278-2626; 1090-2147
• DOI: 10.1016/j.bandc.2006.01.002

Core symptoms of Tourette’s syndrome (TS) and obsessive-compulsive disorder (OCD) may be attributed to an impairment in inhibitory control. Neuropsychological studies have addressed inhibition in both disorders, but findings have been inconsistent. The aim of this study was to examine cognitive inhibition, using a semantic Simon effect paradigm, in patients with TS and OCD. Furthermore, to address comorbidity a group of TS + OCD patients was also examined. Results indicated that patients with TS and OCD were affected by the inhibitory components of the task. TS groups performed similarly to controls on simple and choice RT tasks, but were particularly compromised as increasingly complex inhibitory demands were imposed. OCD patients were slower and committed more errors than controls, especially in the more cognitively demanding conditions, and were particularly disadvantaged by incongruent stimulus-response compatibilities. Findings implicate possible fronto-striatal dysfunction, are consistent with previously reported inhibitory deficits in TS and OCD, and support the theory that comorbid TS + OCD is more closely linked to pure TS than OCD.