Research

Freezing of a gait is a debilitating and difficult to treat symptom in Parkinson disease in which walking is halted and the feet feel “glued to the ground.” A variety of triggers can cause freezing of gait, with common examples including maneuvering in small spaces, walking through a doorway, turning and anxiety. In some patients external cues and cognitive strategies--such as walking with rhythmic sounds, stepping on or over a visual target or counting--ameliorate freezing. Importantly, these symptoms are very heterogeneous: only some patients have freezing, and within this group patients differ in what triggers freezing and how they respond to external cues. The goals of this project are to identify cortical circuit activity that predicts susceptibility to freezing and that is associated with freezing onset and recovery from freezing. We expect that different freezing triggers and cueing strategies are associated with dissociable neural mechanisms. By characterizing these mechanisms, we may be able to develop personalized rehabilitation or neuromodulation therapies to improve freezing of gait in the future. This project uses mobile EEG and wearable inertial sensors during a walking task incorporating multiple freezing trigger types in an ecologically valid clinic setting.

Movement initiation and rhythmic actions are impaired in patients with Parkinson’s disease. Reward and sensory cues, such as visual targets and rhythmic auditory tones, can improve movements in some patients. The mechanisms of this improvement are poorly understood, and in particular the reasons for heterogeneity across patients has been largely ignored in the literature. In this project, we aim to collect a rich dataset on a relatively large population of patients and relate the degree of benefit as measured by kinematic analyses to brain activity on multiple spatial and temporal scales to understand how various different cues facilitate movement. This project uses markerless video kinematics, high-density EEG, functional and structural MRI, and intracranial recordings during deep brain stimulation surgery during upper extremity movement tasks.

Passively observing actions and imagining performing actions activates neural representations of movement. These strategies have been proposed as potential rehabilitation techniques for movement disorders. This project examines involvement of basal ganglia-thalamocortical circuits in action observation and imagery using intracranial recordings in patients with Parkinson disease and Essential tremor.