The aim of this study was to analyze the different forms of leg tremors exhibited while standing in patients with Parkinson disease (PD), and to determine if the type of leg tremor exhibited is indicative of prognosis or treatment response in PD patients.

We studied the clinical characteristics of five PD patients (all women; mean age, 59 years, range, 53–64 years) with unilateral standing leg tremor as the initial manifestation of PD, including their electrophysiological findings and the results of long-term follow-up.

For each patient, parkinsonism either existed at the time of onset of the initial symptoms or developed later. Patient responses to drugs were generally good, but one patient showed a poor response to drugs, even though she had only a low frequency leg tremor. For two patients whom we could observe during the 10-year follow-up period, neither the leg tremor nor parkinsonism was aggravated.

There are two forms of unilateral standing leg tremor in PD. One form is high frequency, similar to the primary orthostatic tremor. The other is low frequency and similar to the parkinsonian resting tremor. Based on these observations, it appears that progression might be slow if PD patients have standing leg tremor as the initial manifestation.