Influence of education on the relationship between white matter lesions and cognition

OBJECTIVE: To test the hypothesis that education level modulates the effects of cerebral white matter hyperintensities (WMH) on cognition in a large population-based study. METHODS: A total of 845 elderly subjects aged 64 to 76 years who enrolled in a longitudinal study on cognitive decline and vascular aging had an MRI examination. Cognitive functions were assessed by Mini-Mental State Examination, Trail Making Test Part B, Digit Symbol Substitution Test of the Wechsler Adult Intelligence Scale-Revised, Finger Tapping Test, Word Fluency Test, and Raven Progressive Matrix. MRI scans were interpreted visually using a standardized scale for rating WMH. RESULTS: Severe WMH were present in 17% of the participants who had lower performances on tests involving attention tasks. In participants with a lower level of education, presence of severe WMH was significantly associated with lower cognitive performances. This was found for all cognitive tests. Conversely, in participants with a high level of education, there was no significant association between severity of WMH and level of cognitive functions. CONCLUSION: Education modulates the consequences of WMH on cognition. Participants with a high level of education were protected against the cognitive deterioration related to vascular insults of the brain.