Orthostatic Tremor: Pathophysiology Guiding Treatment

Purpose of review: Orthostatic tremor (OT) is a rare disorder characterized by tremor and a feeling of unsteadiness while standing that resolve upon walking or sitting. A pathognomonic 13–18 Hz tremor is seen on surface EMG while standing. Though its clinical features have been better defined over time, much of its pathophysiology remains unknown and treatment options are limited. We review here recent developments in both of these areas. Recent findings: Several recent studies have furthered our understanding of the central oscillatory network involved in OT. fMRI and ¹⁸F-FDG-PET studies have identified a ponto-cerebello-thalamo-cortical network underlying OT, though the nature of its dysfunction remains unknown. Randomized trials of treatments for OT are few, so most data are from case reports or small case series. Clonazepam and gabapentin are likely the most effective medical therapies, while bilateral ventral intermediate nucleus deep brain stimulation shows promise for refractory cases. Summary: Though much about OT remains unknown, our understanding of its pathophysiology has improved through recent studies. Treatment benefit is overall modest and inconsistent, though better understanding of the disease could lead to new avenues for treatment.