Objective: The aim of this study is to observe the nature of visible leg tremor in heterogeneous patients who complained the leg tremor.

Background: Orthostatic tremor (OT) is a kind of isometric tremor characterized by 13-18 Hz high frequency tremor of legs that enhanced at standing and disappeared at sitting. The pathophysiology of OT is not clear yet but central tremor generator of the cerebellum or brainstem might be associated with OT. The most common cause of OT is “idiopathic”, but Parkinson’s disease (PD), pontine lesions, cerebellar degeneration, and head trauma were known to another causes of OT.

Methods: We evaluated 7 patients who complained the leg tremor as an initial hardest symptom and leg tremor was visible with the eye. Leg tremor of each patient was recorded by video, and tremor of another body part and detailed neurological examination were done by movement specialist. The Unified Parkinson’s disease rating scale (UPDRS) was checked in patients who showed parkinsonism. Demographic variables, brain magnetic resonance imaging (MRI), [¹⁸F]-FP-CIT brain positron emission topography (PET), surface electromyographic (EMG) results and response to medication were analyzed retrospectively with previous medical records. Treatment response was divided by three groups such as good, moderate and poor.

Results: Two patients showed the each structural lesion on the paramedian pontomesencephalic junction, and caudate nucleus in MRI. Two patients showed tremor of one more body part except legs, and four patients showed parkinsonism. In these patients, three patients were done [¹⁸F]-FP-CIT PET. Two patients showed the decreased uptake of both posterior putamen and another one showed normal uptake pattern. The tremor patterns and frequency were various using surface EMG. EMG phase relationship between the signals varied among individuals as well as within the same individual. This variation included co-contraction, alternating contraction and mixed patterns. Treatment response was various, good (1/3), moderate (1/3) and poor (1/3). The remainder was not treated because the patient was suspicious of functional leg tremor.

Conclusions: We found that visible leg tremor did not show uniform patterns and showed various responses to treatment. To evaluate the pathophysiology of leg tremor, more patients and detailed analysis of tremor could be needed.

« Back to 2016 International Congress

MDS Abstracts - https://www.mdsabstracts.org/abstract/the-visible-leg-tremor-at-standing-is-always-orthostatic-tremor/