Executive function in Tourette's syndrome and obsessive-compulsive disorder.
BACKGROUND
Cognitive performance was compared in the genetically and neurobiologically related disorders of Tourette's syndrome (TS) and obsessive-compulsive disorder (OCD), in three domains of executive function: planning, decision-making and inhibitory response control.


METHODS
Twenty TS patients, twenty OCD patients and a group of age- and IQ-matched normal controls completed psychometric and computerized cognitive tests and psychiatric rating scales. The cognitive tests were well-characterized in terms of their sensitivity to other fronto-striatal disorders, and included pattern and spatial recognition memory, attentional set-shifting, and a Go/No-go set-shifting task, planning, and decision-making.


RESULTS
Compared to controls, OCD patients showed selective deficits in pattern recognition memory and slower responding in both pattern and spatial recognition, impaired extra-dimensional shifting on the set-shifting test and impaired reversal of response set on the Go/No-go test. In contrast, TS patients were impaired in spatial recognition memory, extra-dimensional set-shifting, and decision-making. Neither group was impaired in planning. Direct comparisons between the TS and OCD groups revealed significantly different greater deficits for recognition memory latency and Go/No-go reversal for the OCD group, and quality of decision-making for the TS group.


CONCLUSIONS
TS and OCD show both differences (recognition memory, decision-making) and similarities (set-shifting) in selective profiles of cognitive function. Specific set-shifting deficits in the OCD group contrasted with their intact performance on other tests of executive function, such as planning and decision-making, and suggested only limited involvement of frontal lobe dysfunction, possibly consistent with OCD symptomatology.
Watkins
Laura H
LH
MRC Cambridge Centre for Brain Repair, University of Cambridge, Cambridge, UK.
Sahakian
Barbara J
BJ
Robertson
Mary M
MM
Veale
David M
DM
Rogers
Robert D
RD
Pickard
Kathryn M
KM
Aitken
Michael R F
MR
Robbins
Trevor W
TW
D000328:Adult; D001288:Attention / Q000502:physiology; D001321:Autistic Disorder / Q000175:diagnosis* / Q000473:pathology / Q000503:physiopathology; D003657:Decision Making / Q000502:physiology*; D005260:Female; D005625:Frontal Lobe / Q000473:pathology / Q000503:physiopathology; D005717:Games, Experimental; D006801:Humans; D007266:Inhibition, Psychological; D008297:Male; D008609:Mental Status Schedule / Q000706:statistics & numerical data; D008875:Middle Aged; D009415:Nerve Net / Q000473:pathology / Q000503:physiopathology; D009483:Neuropsychological Tests / Q000706:statistics & numerical data*; D011340:Problem Solving / Q000502:physiology*; D011594:Psychometrics; D012718:Set, Psychology; D013223:Statistics as Topic; D013702:Temporal Lobe / Q000503:physiopathology