title: White matter hyperintensities and subclinical infarction: associations with psychomotor speed and cognitive flexibility.
abstract: OBJECTIVE
  We examined white matter hyperintensity volume (WMHV) and subclinical infarction (no history of clinical stroke; SI) in relation to performance on tests of sequencing, cognitive flexibility, and sensorimotor ability.
  
  
  METHODS
  The Northern Manhattan Study includes a stroke-free community-based sample of Hispanic, Black, and White participants. A subsample (n=656) has undergone measurement of WMHV, SI, and neuropsychological testing. Linear regression was used to examine WMHV and SI in relation to performance on tests of sequencing as measured by Color Trails 1, cognitive flexibility as measured by Color Trails 2, and sensorimotor ability as measured by Grooved Pegboard, using generalized estimating equations (GEE) to account for the correlation among the cognitive tests and other covariates.
  
  
  RESULTS
  Considering performance on the tests of sequencing, cognitive flexibility, and sensorimotor ability simultaneously using GEE, WMHV and subclinical infarction were each associated with worse cognitive performance globally. There was a threshold effect for WMHV with those in the upper quartile performing significantly worse on the tests of cognitive flexibility and sensorimotor ability. Those with frontal SI performed worse on the test of cognitive flexibility and those with deep SI, worse on the test of sequencing.
  
  
  CONCLUSIONS
  Both SI and WMHV were associated with globally worse cognitive performance. Participants with WMH affecting more than 0.75% of cranial volume had significantly slower performance on a task of cognitive flexibility and sensorimotor ability than those in the lowest quartile. The effects of SI on cognitive performance varied by location.
authors.affiliation: Division of Stroke and Critical Care, Department of Neurology, College of Physicians and Surgeons of Columbia University, NI-Room 640, 710 W168th Street, New York, NY 10032, USA. cbw7@columbia.edu
authors.forename: Clinton B
authors.initials: CB
authors.lastname: Wright
authors.forename: Joanne R
authors.initials: JR
authors.lastname: Festa
authors.forename: Myunghee C
authors.initials: MC
authors.lastname: Paik
authors.forename: Alexis
authors.initials: A
authors.lastname: Schmiedigen
authors.forename: Truman R
authors.initials: TR
authors.lastname: Brown
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Yoshita
authors.forename: Charles
authors.initials: C
authors.lastname: DeCarli
authors.forename: Ralph
authors.initials: R
authors.lastname: Sacco
authors.forename: Yaakov
authors.initials: Y
authors.lastname: Stern
mesh_terms: D000368:Aged; D002544:Cerebral Infarction / Q000175:diagnosis* / Q000503:physiopathology* / Q000523:psychology; D003071:Cognition; D015331:Cohort Studies; D005260:Female; D006801:Humans; D049292:Leukoaraiosis / Q000175:diagnosis*; D016014:Linear Models; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011597:Psychomotor Performance; D012720:Severity of Illness Index; D013997:Time Factors