Orthostatic Tremor.

Orthostatic tremor (OT) is a rare movement disorder characterized by high-frequency (13-18 Hz) tremor in the legs and trunk during standing and relieved by sitting or walking. While OT is frequently an isolated disorder, some patients may have comorbid neurological conditions, such as essential tremor and parkinsonism, the so-called OT Plus. The pathophysiology of OT is not well-understood, and a specific central oscillator remains elusive, but current evidence suggests that ascending spinocerebellar and proprioceptive inputs, cerebellar processing, cerebello-thalamo-cortical signals, and cortico-muscular coupling play a role in the pathophysiology of OT, suggesting that this is a network disorder. The treatment of OT is challenging, but pharmacological therapy includes gabapentin, clonazepam, perampanel, and levodopa. While spinal cord stimulation seems promising for selected patients, deep brain stimulation is mainly employed in severe cases, resulting in modest improvement in standing tolerance.