Treatment of Orthostatic Tremor

Abstract

Orthostatic tremor (OT) is manifested as a rapid tremor of the lower extremities while standing. The patients usually present with a feeling of unsteadiness while standing but typically have no symptoms while sitting or walking. On examination, the patients may present with a palpable fine rippling of the quadriceps muscles, and a whirring sound, like a helicopter rotor, which may be heard when the diaphragm of the stethoscope is placed behind the knee. The diagnosis can be confirmed with concentric needle EMG of the quadriceps muscles with a frequency of 13–18 Hz while standing. The most commonly recommended first-line drug is clonazepam. Second-line therapies include gabapentin, levodopa, primidone, phenobarbital, levetiracetam, sodium valproate, and pramipexole which can be used as monotherapy or in combination with clonazepam. Gabapentin has shown to improve symptoms when used as add-on therapy in patients with OT. Bilateral Vim thalamic DBS implantation may be performed in a few refractory cases of orthostatic tremor with improvement in standing time.