White matter lesions and cognitive performance: The role of cognitively complex leisure activity

Background. Among persons with white matter lesions (WMLs), there is a range of cognitive function. We examine whether participation in leisure activities modifies the effect of WML load on cognitive function. Methods. Data are from 2300 men and women (aged 66-92 years) participating in the population-based Age Gene/Environment Susceptibility-Reykjavik Study. Subcortical WML load was calculated as a weighted sum, based on size of lesions in the four lobes. Periventricular WML load was calculated as the sum of lesion scores. based on size, for the frontal caps, occipitoparietal caps and bands. The upper quartile of lesion load in either area was compared to the lower three quartiles. Composite scores of memory (MEM), speed of processing (SP), and executive function (EF) were constructed from a battery of neuropsychological tests. Frequency of participation in nine cognitively stimulating leisure activities was assessed via questionnaire; the upper quartile was compared to the lower three quartiles. Multiple regression, controlling for demographic and health factors and brain infarcts, was used to test the main effects and interaction of WMLs and leisure activity on cognitive function. Results. High leisure activity was associated with higher performance in all three cognitive abilities: MEM beta = 0.20, 95% confidence interval [CI], 0.11-0.29: SP beta = 0.37, 95% CI, 0.29-0.45; and EF beta = 0.23, 95% CI, 0.15-0.29. High WML load was associated with significantly lower performance in SP (P = -0.06. 95% CI, -0.13 to -0.01). The effect of WMLs on SP performance was modified by high leisure activity (p for interaction < .05). Conclusion. Participation in cognitively stimulating leisure activity may attenuate the effect of WML pathology on cognitive performance.