title: No evidence for left superior temporal dysfunction in asymptomatic schizophrenia and bipolar disorder. PET study of verbal fluency.
abstract: BACKGROUND
  Positron emission tomography (PET) studies have revealed functional left superior temporal gyrus (STG) abnormalities in symptomatic schizophrenia during word generation.
  
  
  OBJECTIVE
  To discover if this dysfunction is present in asymptomatic schizophrenia. To determine whether, without concurrent symptomatology, schizophrenia and bipolar affective disorder (BPD) are distinguishable by differing regional cerebral blood flow (rCBF) patterns during word generation.
  
  
  METHODS
  A PET verbal fluency protocol was applied to six patients with BPD in remission and six patients with asymptomatic schizophrenia. Analysis included 10 control subjects from a contemporaneous study.
  
  
  RESULTS
  All groups showed relative reduction of rCBF in both superior temporal cortices. There were no quantitative differences in any group comparison. All groups exhibited negative covariation between rCBF in left prefrontal and right (but not left) temporal regions.
  
  
  CONCLUSIONS
  Abnormal patterns of left STG function cannot be regarded as a trait marker for schizophrenia. Functional abnormalities may reflect aspects of mental state.
authors.affiliation: Imperial College School of Medicine, Department of Psychiatry, Charing Cross Hospital, London. s.dye@ic.ac.uk
authors.forename: S M
authors.initials: SM
authors.lastname: Dye
authors.forename: S A
authors.initials: SA
authors.lastname: Spence
authors.forename: C J
authors.initials: CJ
authors.lastname: Bench
authors.forename: S R
authors.initials: SR
authors.lastname: Hirsch
authors.forename: M D
authors.initials: MD
authors.lastname: Stefan
authors.forename: T
authors.initials: T
authors.lastname: Sharma
authors.forename: P M
authors.initials: PM
authors.lastname: Grasby
mesh_terms: D000328:Adult; D001714:Bipolar Disorder / Q000000981:diagnostic imaging / Q000503:physiopathology*; D001927:Brain Diseases / Q000000981:diagnostic imaging* / Q000503:physiopathology; D016022:Case-Control Studies; D002560:Cerebrovascular Circulation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012559:Schizophrenia / Q000000981:diagnostic imaging / Q000503:physiopathology*; D013702:Temporal Lobe / Q000000981:diagnostic imaging* / Q000503:physiopathology; D014055:Tomography, Emission-Computed; D014705:Verbal Behavior / Q000502:physiology