Objective: To determine association of brain white matter microvascular lesion burden with cognition, motor function, and driving in mild Parkinson’s disease (PD).

Background: Brain white matter lesion burden is associated with poorer cognition in PD across stages of severity.

Method: At baseline of an ongoing clinical trial on aerobic exercise, independently living, legally driving PD patients underwent morphometric 3T MRI, motor and cognitive testing, and a 20 mile road-test in an instrumented vehicle. White matter lesion burden was based on total white matter hypointensity volume from T1-weighted images using FreeSurfer analysis, which strongly correlates with white matter hyperintensities on T2-FLAIR images.

Results: Forty-three PD patients completed MRI (Age mean±SD=66.0±7.6; 31 men, 12 women). Their median Hoehn-Yahr stage was II (range I-II), median MMSE was 29 (range 26-30) and median Geriatric Depression Scale score was 0 (range 0-3). A subset had well controlled systemic comorbidities such as hypertension or diabetes mellitus. They all were able complete a maximal cardiopulmonary exercise test without complications as a requirement for enrollment in the exercise study. As white matter lesion burden was not normally distributed, non-parametric methods were used for analysis. White matter lesion burden correlated positively with age (Spearman’s rho=0.58, p<0.001), MDS-UPDRS motor score (rho=0.32, p=0.040), at-fault driving error counts (rho=0.59, p<0.001); and negatively with MOCA score (rho=-0.48, p=0.001). These significant correlations persisted after adjusting for age. The white matter lesion burden discriminated between patient groups with normal MoCA (≥26, n=18) and abnormal MoCA scores <26 (n=25), p<0.001 (Mann-Whitney U test). Probing cognition further revealed negative correlations between white matter lesion burden and Delayed Verbal Recall (p=0.019), Block Design (p=0.020), Eriksen’s Flanker task (p=0.007), and Trail Making Subtest B performance (p=0.005), but only the association with Flanker Task persisted after adjusting for age (p=0.006).

Conclusion: White matter lesion burden even in relatively mild and healthy patients with PD is associated with poorer cognition (especially executive functions), motor function, and instrumental ADL (driving) outcomes.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/white-matter-lesion-burden-is-associated-with-poorer-clinical-and-driving-outcomes-in-mild-parkinsons-disease/