Unraveling the twists and turns of Freezing of Gait in Parkinson's Disease - A multimodal neuroimaging investigation

Freezing of gait (FOG) is a complex and disabling symptom for people with Parkinson’s disease (PD). FOG is usually triggered in specific gait situations, with turning being the most provocative. So far, the reasons why turning causes gait breakdown are not yet known. Based on previous experimental work, high asymmetry and small step length are two candidates that may either separately or in combination, lead to FOG. To tease these apart, we independently manipulate asymmetry and step size on a split-belt treadmill to study freezing-related deficits of motor control. Further, the neural correlates of turning-related asymmetric motor control have not been studied, owing to limitations of previous paradigms. We therefore propose a novel asymmetric foot movement task during functional MRI to study freezing-related brain network interactions during asymmetric motor control. Finally, we will link the functional networks underlying asymmetric motor control with the freezing-related cortical brain activity measured during asymmetric upright walking. Combining novel behavioral and neuroimaging paradigms, this work will shed light on the precise motor control deficits in FOG. Importantly, we expect to provide concrete targets for future prospective and interventional work to detect risk and intervene optimally, and maximize the impact on FOG.