INTRODUCTION
PD, peripheral muscle fatigue, bradykinesia
MOVEMENT DISORDERS, DISEASE
The sequence effect is the progressive deterioration in ongoing movement that is not related to peripheral muscle fatigue [Although different components of bradykinesia can be treated with levodopa and/or deep brain stimulation (DBS), a critical unmet need for improving the lives of people with PD is that the sequence effect does not respond to dopaminergic medication [Our goal in this study was to investigate whether the sequence effect improved during subthalamic nucleus (STN) DBS in people with PD and whether there was a ‘dose” or DBS intensity dependence. We measured the sequence effect during repetitive wrist flexion-extension, correlated it with the Movement Disorders Society-Unified Parkinson’s Disease Rating Scale (MDS-UPDRS III) and with its sub-score of lateralized bradykinesia and demonstrated that it became worse over time in the off therapy state, but improved with STN DBS.