Shaking on Standing: A Critical Review

Abstract

Orthostatic tremor is a rare condition, though its exact prevalence is unknown, which is clinically characterized by a feeling of unsteadiness or being about to fall on standing and which disappears on walking, sitting, or lying down. It is generally accepted that classic orthostatic tremor manifests with a highfrequency tremor (>13 Hz) of the legs when standing. However, a number of patients initially reported as orthostatic tremor did not actually have such electrophysiological features. It is our experience that there is a clinical spectrum of different conditions presenting as shaking on standing, and this highlights the importance of the electrophysiology to aid the differential diagnosis of these disorders. Here, we provide a critical review of the clinical spectrum of shaking on standing, along with demonstrative electrophysiological recordings of some of these conditions.

Lessons I have learned from my patients: everyday life with primary orthostatic tremor

“…They have greater gait disturbances at an early stage and a higher risk of falls [10] and overall, slow orthostatic tremor (<10Hz) bears little resemblance with POT [10]. Extensive description of secondary orthostatic tremors is beyond our scope as a number of them did not have the typical high frequency tremor [11, 12]. Some findings are in favour of secondary orthostatic tremor (Table 3).…”

“…Some findings are in favour of secondary orthostatic tremor (Table 3). Medic, Dysmetria, ataxia, eye movement disorders, sensory deficits or limbs weakness, combined with medical history (including neuroleptics of recreational solvants absorption) and structural abnormalities on brain or spinal cord imaging are valuable clues for symptomatic orthostatic tremor (Table 3) [11, 12]. …”

Orthostatic Myoclonus Secondary to Central Pontine Myelinolysis

“…A surface electromyography (SEMG) demonstrated nonrhythmic short bursts (<100 ms) in a 9‐ to 10‐Hz frequency in the quadriceps and biceps femoris muscles, which appeared in the upright position and then disappeared when sitting (Fig. ; Video 2), fulfilling the criteria for OM . There was no cortical activity associated with the myoclonus when assessed by jerk‐locked back averaging.…”

“…Orthostatic myoclonus (OM) is a recently reported cause of “unsteadiness” or “shaky legs” during orthostatism and gait . We report on a middle‐aged woman with OM secondary to a central pontine myelinolysis (CPM).…”

Slow orthostatic tremor and the case for routine electrophysiological evaluation of all tremors

“…In most instances, primary (classic) OT is an isolated tremor syndrome, 8 and slow OT is typically a combined tremor syndrome that is pathophysiologically related to a variety of specific neurologic conditions. 9 Virtually, all cases of “isolated” slow OT in Table 1 of Hassan and Caviness have atypical tremor characteristics that do not resemble primary OT. For example, the EMG discharges in Figure 1 of Coffeng et al 10 are not convincingly coherent and are clearly arrhythmic.…”