title: Inhibitory deficits in Tourette syndrome: a function of comorbidity and symptom severity.
abstract: This study examined central inhibitory function in children with Tourette syndrome (TS; N = 46) and normally developing controls (N = 22) matched on age, gender, and IQ. A negative priming task measured the ability to inhibit processing of irrelevant distractor stimuli presented on a visual display. Initial analyses indicated that participants with Tourette syndrome did not differ significantly in inhibitory function from controls. However, when the large Tourette syndrome sample was separated into subgroups, one without evidence of comorbidity (N = 23) and the other meeting research criteria for either AD/HD, OCD, or both (N = 23), it became evident that individuals with Tourette syndrome with comorbid conditions tended to perform less well than the control group, whereas those without comorbidity performed much like controls. Similarly, when the large Tourette syndrome sample was divided into two subgroups on the basis of severity of symptomatology (N = 23 in each), those with more numerous and severe symptoms of Tourette syndrome, AD/HD, and OCD performed significantly less well than both controls and Tourette syndrome subjects with fewer and less severe symptoms. This suggests that neuropsychological impairment occurs as a function of comorbidity and symptom severity in Tourette syndrome. It also suggests that categorical diagnoses alone may be less useful than dimensional methods for predicting cognitive impairment in individuals with Tourette syndrome.
authors.affiliation: University of Utah, Department of Psychology, Salt Lake City 84112-0251, USA. ozonoff@psych.utah.edu
authors.forename: S
authors.initials: S
authors.lastname: Ozonoff
authors.forename: D L
authors.initials: DL
authors.lastname: Strayer
authors.forename: W M
authors.initials: WM
authors.lastname: McMahon
authors.forename: F
authors.initials: F
authors.lastname: Filloux
mesh_terms: D000293:Adolescent; D001289:Attention Deficit Disorder with Hyperactivity / Q000150:complications*; D002648:Child; D003627:Data Interpretation, Statistical; D004192:Discrimination, Psychological; D005260:Female; D006801:Humans; D007266:Inhibition, Psychological; D008297:Male; D009483:Neuropsychological Tests; D009771:Obsessive-Compulsive Disorder / Q000150:complications*; D011597:Psychomotor Performance; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D005879:Tourette Syndrome / Q000150:complications* / Q000175:diagnosis / Q000503:physiopathology*