Impaired resting vagal tone in patients with functional movement disorders.

Introduction: The autonomic nervous system plays an integral role in the maintenance of homeostasis during times of stress. The functioning of the autonomic nervous system in patients with functional movement disorders (FMD) is of particular interest given the hypothesis that converted psychological stress plays a critical role in FMD disease pathogenesis. We sought to investigate autonomic nervous system activity in FMD patients by examining heart rate variability (HRV), a quantitative marker of autonomic function.