title: Performance on Wechsler intelligence scales in children with Tourette syndrome.
abstract: BACKGROUND
  There is some evidence that Tourette syndrome is associated with cognitive disabilities.
  
  
  OBJECTIVE
  To examine the cognitive performance of a clinical cohort of children with Tourette syndrome.
  
  
  METHODS
  266 children with Tourette syndrome have been examined with Wechsler Intelligence Scales. The presence of the co-morbidities attention deficit hyperactivity disorder (ADHD) and obsessive-compulsive disorder (OCD) was assessed using validated diagnostic instruments. Eighty healthy controls matched a part of the TS cohort.
  
  
  RESULTS
  The children with Tourette syndrome had a mean verbal IQ (VIQ) of 92.9, performance IQ (PIQ) of 87.1, and full-scale IQ (FSIQ) of 88.8. We found statistically significant higher PIQ and FSIQ in the control group compared with a matched TS cohort and a trend towards a higher VIQ among the healthy controls. There was a statistically significant influence of age at onset of tics on PIQ. The children with co-morbid OCD scored higher on FSIQ compared with the other groups. The children with co-morbid ADHD and OCD showed problems in motor tasks and speed tasks and the children with co-morbid ADHD showed attention deficits.
  
  
  CONCLUSIONS
  Children with Tourette syndrome have lower IQ scores than the general population (but less than one standard deviation below) and our control group. Early onset of tics and the presence of co-morbidities might cause specific deficits on cognitive performance.
authors.affiliation: Pediatric Department, Glostrup University Hospital, Ndr. Ringvej, 2600 Glostrup, Denmark. nanettemol@hotmail.com
authors.forename: Nanette M M M
authors.initials: NM
authors.lastname: Debes
authors.forename: Theis
authors.initials: T
authors.lastname: Lange
authors.forename: Tanja L
authors.initials: TL
authors.lastname: Jessen
authors.forename: Helle
authors.initials: H
authors.lastname: Hjalgrim
authors.forename: Liselotte
authors.initials: L
authors.lastname: Skov
mesh_terms: D001289:Attention Deficit Disorder with Hyperactivity / Q000175:diagnosis* / Q000453:epidemiology; D002648:Child; D003072:Cognition Disorders / Q000175:diagnosis* / Q000453:epidemiology; D005260:Female; D006801:Humans; D008607:Intellectual Disability / Q000175:diagnosis* / Q000453:epidemiology; D008297:Male; D009771:Obsessive-Compulsive Disorder / Q000175:diagnosis* / Q000453:epidemiology; D011237:Predictive Value of Tests; D005879:Tourette Syndrome / Q000453:epidemiology* / Q000523:psychology