title: Duration effect of obsessive-compulsive disorder on cognitive function: a functional MRI study.
abstract: BACKGROUND
  The inconsistency of previous reports examining cognitive function in obsessive-compulsive disorder (OCD) suggests its heterogeneity. In this study, we examined the effect of illness duration on cognitive function in OCD.
  
  
  METHODS
  We examined the cognitive function of 32 OCD patients and 16 healthy volunteers by neuropsychological tests and functional magnetic resonance imaging while they performed the Stroop and N-back tasks to assess attention and nonverbal memory. The patients were divided into two groups by illness duration: a short-term group (n=17, 5.5+/-3.1 years) and a long-term group (n=15, 20.3+/-6.1 years). Statistical analysis was performed to determine the differences between these two groups and the normal control group (n=16).
  
  
  RESULTS
  The long-term group showed attention deficit and nonverbal memory dysfunction on the neuropsychological tests. In contrast, on functional magnetic resonance imaging, the short-term group showed weaker activation of the right caudate during the Stroop task and stronger activation of the right dorso-lateral prefrontal cortex during the N-back task than the long-term and normal control groups.
  
  
  CONCLUSIONS
  The results suggested that abnormal brain activation occurs in the early phase of OCD and that the long-term persistence of OCD might involve a decline in cognitive function.
authors.affiliation: Department of Neuropsychiatry, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, Japan. tomona@npsych.med.kyushu-u.ac.jp
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Nakao
authors.forename: Akiko
authors.initials: A
authors.lastname: Nakagawa
authors.forename: Takashi
authors.initials: T
authors.lastname: Yoshiura
authors.forename: Eriko
authors.initials: E
authors.lastname: Nakatani
authors.forename: Maiko
authors.initials: M
authors.lastname: Nabeyama
authors.forename: Hirokuni
authors.initials: H
authors.lastname: Sanematsu
authors.forename: Osamu
authors.initials: O
authors.lastname: Togao
authors.forename: Kazuko
authors.initials: K
authors.lastname: Yoshioka
authors.forename: Mayumi
authors.initials: M
authors.lastname: Tomita
authors.forename: Toshihide
authors.initials: T
authors.lastname: Kuroki
authors.forename: Shigenobu
authors.initials: S
authors.lastname: Kanba
mesh_terms: D000293:Adolescent; D000328:Adult; D001921:Brain / Q000503:physiopathology*; D002421:Caudate Nucleus / Q000503:physiopathology; D003072:Cognition Disorders / Q000175:diagnosis / Q000503:physiopathology* / Q000523:psychology; D004292:Dominance, Cerebral / Q000502:physiology; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology; D008875:Middle Aged; D009483:Neuropsychological Tests / Q000706:statistics & numerical data*; D009771:Obsessive-Compulsive Disorder / Q000175:diagnosis / Q000503:physiopathology* / Q000523:psychology; D017397:Prefrontal Cortex / Q000502:physiology; D011594:Psychometrics; D012153:Retention, Psychology / Q000502:physiology; D057190:Stroop Test; D055815:Young Adult