title: Cerebral blood flow velocity decreases during cognitive stimulation in Huntington's disease.
abstract: OBJECTIVE
  To examine whether activation of cerebral blood flow velocity during cognitive stimulation, as measured by transcranial Doppler ultrasonography (TCD), is altered in patients with Huntington's Disease (HD).
  
  
  BACKGROUND
  Previous research suggests that resting cerebral blood flow in symptomatic and asymptomatic HD patients is reduced from expected premorbid levels. The effects of cognitive activation on this relative hypoperfusion in HD has not been studied extensively.
  
  
  METHODS
  We measured TCD flow velocity during rest and cognitive testing with the Porteus Maze Test and the Trails Test in 12 normal control subjects and 10 gene-positive HD patients. Percent change (i.e., flow during testing/resting) of flow velocity in the anterior and middle cerebral arteries were compared between groups. Correlations among percent flow velocity change, a disability rating scale, and cognitive test scores were calculated.
  
  
  RESULTS
  In control subjects, anterior cerebral artery flow velocity and middle cerebral artery velocity increased during cognitive testing (p=0.001). HD patients showed a smaller blood flow velocity increase in the anterior cerebral arteries during the Porteus Maze Test (p < 0.001) and the Trails Test, Part B (p < 0.001). In the left anterior cerebral artery, flow velocity fell an average of 4.2% below resting baseline levels during the Porteus Maze Test, and 1.2% below resting levels during the Trails Test. The magnitude of the cerebral blood flow velocity changes in the anterior cerebral artery correlated with a number of cognitive test scores and with a rating scale of functional disability. In addition, logistic regression was able to discriminate the HD patients from the control group based on blood flow velocity changes (p=0.0025). When HD patients were divided into more (i.e., HD with chorea; n=4) and less impaired (i.e., without chorea; n=6) groups, both showed significant decreases in left anterior cerebral artery flow velocity during visual spatial executive cognition testing compared with control subjects.
  
  
  CONCLUSIONS
  These results suggest that activation of visual spatial executive functions cause decreased flow velocity in the anterior cerebral artery, but not the middle cerebral artery, in HD patients. These changes are related to test performance and functional capabilities.
authors.affiliation: Department of Psychiatry, Huntington's Disease Treatment Center, University of Connecticut Medical School, Farmington 06030-2103, USA.
authors.forename: A W
authors.initials: AW
authors.lastname: Deckel
authors.forename: D
authors.initials: D
authors.lastname: Cohen
authors.forename: R
authors.initials: R
authors.lastname: Duckrow
mesh_terms: D000203:Activities of Daily Living; D000328:Adult; D001783:Blood Flow Velocity; D002560:Cerebrovascular Circulation / Q000502:physiology*; D003071:Cognition / Q000502:physiology*; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D006816:Huntington Disease / Q000503:physiopathology* / Q000534:rehabilitation; D008297:Male; D018782:Maze Learning; D008875:Middle Aged; D009483:Neuropsychological Tests; D015203:Reproducibility of Results