Supplementary motor area microstructure defines the extent of gait impairment in Parkinson’s disease

Gait disorders and freezing of gait are challenging symptoms in Parkinson’s disease. Cortical gait centers as the supplementary motor area appear to be relevant in gait control. We hypothesize that diffusion-MRI microstructural markers in this area are associated with quantitative gait performance in participants with Parkinson’s Disease. Retrospective clinical data showed that lower fractional anisotropy in the right supplementary motor cortex was associated with better performance in various bilateral quantitative gait parameters at normal speed, maximal velocity, and especially during cognitively demanding conditions as dual-tasking. Gait performance did not correlate with cortical thickness. In contrast, the correlation between gait and microstructure in the supplementary motor area could indicate that diffusion-MRI might function as a clinical biomarker. The added value might support the clinical prognosis and aid in the development of new interventions, such as localized and personalized stimulation techniques.