White matter hyperintensities are associated with impairment of memory, attention, and global cognitive performance in older stroke patients

Background-The importance of white matter hyperintensities (WMH) for cognitive performance in older stroke patients is largely unknown. We hypothesized that processing speed and executive dysfunction will be associated with frontal WMH whereas impaired memory will be associated with temporal WMH. Methods-Neuropsychological assessments using the Cambridge Cognitive Examination (CAMCOG) and the Cognitive Drug Research (CDR) were completed for 96 stroke survivors aged older than 75 and 23 age-matched controls. Magnetic resonance imaging whole-brain axial FLAIR images were undertaken to visualize WMH and an automated threshold technique was used to determine their volume. Results-In comparison to controls, the stroke patients had significantly greater volume of WMH in all key areas. Within the stroke group, a consistent pattern of significant association was identified between total and frontal WHM volumes and attention and processing speed tasks (eg, choice reaction time [right: R = 0.24 P = 0.02; left: R = 0.26, P = 0.01]), but not with executive function. There were significant associations between memory and temporal WMH volumes ( right: R = 0.27, P = 0.008; left: R = 0.20, P = 0.047). Conclusion-In older stroke patients, cognitive processing speed and performance on measures of attention are significantly associated with WMH volume, particularly in the frontal lobe regions, whereas memory impairment is associated with the volume of temporal lobe WMH.