title: Cerebral microbleeds and cognition in patients with symptomatic small vessel disease.
abstract: OBJECTIVE
  Cerebral microbleeds (CMBs) are common in cerebral small vessel disease. They may cause cognitive impairment, possibly via white matter tract disruption but previous studies have produced inconsistent results. We determined whether CMB number and location are associated with impaired cognition in symptomatic small vessel disease and whether any association was independent of other magnetic resonance imaging markers of small vessel disease.
  
  
  METHODS
  One hundred sixteen patients with lacunar stroke and radiological leukoaraiosis were studied. Neuropsychological assessment was performed. CMBs on gradient echo images were assessed using the Brain Observer Microbleed Rating Scale criteria. Magnetic resonance imaging measures, including diffusion tensor imaging, were also analyzed. Associations between cognitive function and the presence, number, and location of CMBs were determined.
  
  
  RESULTS
  CMBs were present in 46 (39.7%) patients. CMB number correlated weakly with executive function (r=0.22; P=0.022) but not with other cognitive indices. CMBs count in the top decile (≥ 9 CMB, N=12) was more strongly associated with poor executive function; this association remained significant after controlling for T2-lesion load, brain volume, lacune count, and mean diffusivity (b=-0.51; P=0.043).
  
  
  CONCLUSIONS
  In symptomatic small vessel disease, CMB number was weakly associated with executive dysfunction. There seemed to be a threshold effect with the association being largely accounted for by an association of impaired executive function with high CMB count. No association of CMBs with other cognitive domains, including processing speed, was found.
authors: Stroke and Dementia Research Centre, St George's, University of London, London SW17 0RE, United Kingdom.
authors: Bhavini
authors: B
authors: Patel
authors: Andrew J
authors: AJ
authors: Lawrence
authors: Ai Wern
authors: AW
authors: Chung
authors: Philip
authors: P
authors: Rich
authors: Andrew D
authors: AD
authors: Mackinnon
authors: Robin G
authors: RG
authors: Morris
authors: Thomas R
authors: TR
authors: Barrick
authors: Hugh S
authors: HS
authors: Markus
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002543:Cerebral Hemorrhage / Q000175:diagnosis / Q000453:epidemiology* / Q000523:psychology; D059345:Cerebral Small Vessel Diseases / Q000175:diagnosis / Q000453:epidemiology* / Q000523:psychology; D003071:Cognition / Q000502:physiology*; D003072:Cognition Disorders / Q000175:diagnosis / Q000453:epidemiology* / Q000523:psychology; D015331:Cohort Studies; D056344:Executive Function / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008833:Microcirculation / Q000502:physiology*; D008875:Middle Aged