Parkinson’s Disease and Parkinsonian Tremor

Abstract

AbstractTremor is a common symptom of hypokinetic-rigid syndromes such as Parkinson disease. The classical tremor of Parkinson disease is an asymmetric pill-rolling resting tremor of the arms, but postural tremor (including re-emergent and pure postural tremor) and kinetic tremor are also very common. Tremor in atypical parkinsonism is often a symmetric postural tremor that can be jerkier in nature. The pathophysiology of rest tremor in Parkinson disease involves abnormal activity within both the basal ganglia and a cerebello-thalamo-cortical motor circuit, driven by altered dopaminergic, noradrenergic, and serotonergic projections arising from the midbrain. The dopaminergic basis of Parkinson’s tremor differs markedly between individuals and between clinical tremor phenotypes. Dopaminergic treatment (levodopa and dopamine agonists) is the first-choice treatment for rest and re-emergent tremor in Parkinson disease, and probably also rest tremor in atypical parkinsonism. Other pharmacological options include anticholinergics, beta-blockers, or even clozapine, although evidence for these treatment strategies is limited. Additionally, stereotactic surgery including focal lesioning and deep brain stimulation of both basal ganglia (GPi and STN) and thalamus (ventral intermediate nucleus, VIM) are effective treatments for most types of tremor in Parkinson disease.