[Parkinsonian tremor, rigidity and flapping tremor]

Abstract

Tremor occurring at rest (4-6 Hz) is considered to be one of the most characteristic symptoms in patients with Parkinson's disease. Yet, an early stages of the disease only 50% of the patients manifest resting tremor. Indeed, about 15% of Parkinsonian patients never display tremor at any stage of the disease. If tremor is present, its type is essential for differential diagnosis. Pill-rolling movement, for instance, is a hallmark of Parkinson's disease. Parkinsonian patients often show postural tremor associated with certain postures or movement, whereas flapping tremor is indicative of metabolic (ex: hepatic) encephalopathy. Parkinsonian rigidity is unique muscular rigidity. If rigidity is abolished by L-dopa or dopamine agonists, this provides a reliable sign for diagnosis of Parkinson's disease. Pathophysiology of different types of tremor is briefly discussed.