title: Education and the cognitive decline associated with MRI-defined brain infarct.
abstract: OBJECTIVE
  To assess whether educational attainment, a correlate of cognitive reserve, predicts the amount of cognitive decline associated with a new brain infarct.
  
  
  METHODS
  The Cardiovascular Health Study is a population-based, longitudinal study of people aged 65 years and older. Cognitive function was measured annually using the Modified Mini-Mental State Examination (3MS) and the Digit-Symbol Substitution Test (DSST). The authors tested whether education level modified 1) the cross-sectional association between cognitive performance and MRI-defined infarct and 2) the change in cognitive function associated with an incident infarct at a follow-up MRI.
  
  
  RESULTS
  In cross-sectional analysis (n = 3,660), MRI-defined infarct was associated with a greater impact on 3MS performance in the lowest education quartile when compared with others (p for heterogeneity = 0.012). Among those with a follow-up MRI who had no infarct on initial MRI (n = 1,433), education level was not associated with the incidence, size, or location of new brain infarct. However, a new MRI-defined infarct predicted substantially greater decline in 3MS scores in the lowest education group compared with the others (6.3, 95% CI 4.4- to 8.2-point decline vs 1.7, 95% CI 0.7- to 2.7-point decline; p for heterogeneity < 0.001). Higher education was not associated with smaller declines in DSST performance in the setting of MRI-defined infarct.
  
  
  CONCLUSIONS
  Education seems to modify an individual's decline on a test of general cognitive function when there is incident brain infarct. These findings are consistent with the hypothesis that cognitive reserve influences the impact of vascular injury in the brain.
authors.affiliation: Department of Neurology, University of California, San Francisco, CA 94143, USA. jacob.elkins@ucsfmedctr.org
authors.forename: J S
authors.initials: JS
authors.lastname: Elkins
authors.forename: W T
authors.initials: WT
authors.lastname: Longstreth
authors.forename: T A
authors.initials: TA
authors.lastname: Manolio
authors.forename: A B
authors.initials: AB
authors.lastname: Newman
authors.forename: R A
authors.initials: RA
authors.lastname: Bhadelia
authors.forename: S C
authors.initials: SC
authors.lastname: Johnston
mesh_terms: D002544:Cerebral Infarction / Q000150:complications* / Q000473:pathology*; D003072:Cognition Disorders / Q000150:complications*; D003430:Cross-Sectional Studies; D004522:Educational Status; D006801:Humans; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging; D009483:Neuropsychological Tests