Orthostatic tremor: an association with essential tremor.

Orthostatic tremor is characterized by tremor of the trunk and legs while standing. Rapid frequency has been emphasized as an important criterion for the diagnosis of this tremor. We observed five patients who had the typical findings of orthostatic tremor but had a wide range of frequencies. All five also had postural hand tremor and a family history of essential tremor, suggesting a relationship between orthostatic tremor and essential tremor. This report also emphasizes the association of orthostatic tremor with painful cramps and a relatively consistent improvement with clonazepam.