A Slow Orthostatic Tremor of Primary Origin

Abstract

Background Orthostatic tremor (OT) is a high-frequency tremor (13–18 Hz) present in the legs when standing. Underlying disease is found in one-third of OT patients. Case report We describe an 86-year-old man with progressive shaking of the legs while standing, which disappears immediately after sitting down or while walking. Polymyography confirmed a tremor of the legs (10–11 Hz) while standing. Magnetic resonance imaging (MRI) and neurologic examination showed no underlying disease. Discussion Primary OT can appear at a lower frequency of 10–11 Hz.

Orthostatic Tremor: A Spectrum of Fast and Slow Frequencies or Distinct Entities?

“…Gait involvement was present in the majority of patients with <13 Hz OT in this study and has been documented in some case reports 14 , 15 but not others. 10 – 12 , 19 Others have also found gait impairment and falls to be relatively infrequent in patients with fast OT. Falls were reported in only four of 26 patients with fast OT in one study, 3 and gait impairment felt to be secondary to OT in only two of 26 patients in another study.…”

“… 10 It has since been documented in case reports and small case series with the term applied to frequencies as low as 4 Hz 11 and as high as 10–11 Hz. 12 Most cases of “slow OT” have been reported in the setting of an underlying disorder, including Grave’s disease, 13 multiple sclerosis, 11 suspected paraneoplastic syndrome, 14 cerebellar ataxia, 15 , 16 and Parkinson’s disease. 17 , 18 Rare cases of “slow OT” as an idiopathic condition not associated with any underlying neurologic disease have also been described.…”

“… 17 , 18 Rare cases of “slow OT” as an idiopathic condition not associated with any underlying neurologic disease have also been described. 12 , 19 Although the clinical and neurophysiologic features of patients with classic or “fast” OT have been reported in several large case series, 3 , 4 , 20 , 21 little is known about the characteristics of <13 Hz cases and the literature is limited to case reports and short case series. The main objective of this study was to describe the characteristics of patients with clinical suspicion of OT who were referred to our Movement Neurophysiology Laboratory and found to have <13 Hz EMG tremor discharges on neurophysiologic testing.…”

Dystonia Associated with Idiopathic Slow Orthostatic Tremor

“…Whereas many previous reports of slow OT in the literature have examined symptomatic cases, 12 , 16 we specifically focused on those with idiopathic slow OT, which has been less reported. A recent report described a 10–11 Hz OT in a patient without underlying brain lesions, and suggested “primary slow OT” as a diagnostic entity, 6 although the authors did not perform coherence analysis. Pseudo-OT has been previously linked to cases of genetic parkinsonism, particularly related to parkin mutations.…”

“… 2 – 4 Slow OT may be symptomatic of midbrain lesions including demyelinating plaques, 5 and has also been reported in Parkinson’s disease (PD). 3 However, there are few reports of idiopathic slow OT in the literature, 6 and its pathophysiology is unknown. 7 We aimed to describe the neurophysiological characteristics of slow OT without underlying symptomatic lesions, and its associated neurological features, in a retrospective review of patients presenting to a large academic movement disorders service.…”