Abstract Body: Introduction: We previously reported an association between ischemic white matter hyperintensities (WMH) lesion volume on brain MRI and declining manual dexterity as measured by the grooved peg board test (GPT). Here we investigated this relationship longitudinally using repeated measures of total WMH, periventricular white matter (PVWMH) and subcortical deep white matter lesions (DWMH) volumes over ten years and compared them to changes in repeated GPT over 10 years. Hypothesis: We hypothesized that increases over time in total WMH, PVWMH, and DWMH volume over time would be associated with declining repeated GPT performance.
Methods: We conducted a longitudinal study of 100 volunteers from GeneSTAR, an ongoing study of families enriched for vascular risk factors and cardiovascular disease, age = 63.3 ± 9.5 years, 60% females, 63% hypertension 22% African Americans. Participants underwent two 3T brain MRI lesion volume measurements and repeated manual dexterity testing using GPT at baseline and after 10–13 years. Total WMH, PVWMH, and DWMH volumes were quantified using automated segmentation software. GPT was calculated as the total time to complete the test with both dominant and non-dominant hand. Changes in total WMH, PVWMH, and DWMH, together with changes in GPT performance over time were analyzed using linear regression adjusting for age, systolic blood pressure, race, sex, and education.
Results: For the dominant hand (Figure 1), changes in PVWMH volume (p = 0.028, R-squared = 0.167) and total WMH volume (p = 0.03, R-squared = 0.168) were significantly associated with changes in GPT performance. In contrast, changes in DWMH volume (p = 0.7, R-squared = 0.0878) were not associated with GPT performance. No significant association were found for the nondominant hand. (Figure 2)
Conclusions: In middle-aged adults enriched for risk of for cardiovascular disease, progression of total WMH volume and PVWMH volume are correlated with declining manual dexterity. No significant correlation was observed for the non-dominant hand suggesting differences in the impact of WMH progression on motor function between dominant and non-dominant sides.
Future research should investigate whether interventions targeting vascular risk factors can slow WMH progression and associated motor decline in this at-risk population.