Essential tremor-the most common movement disorder in older people.
Essential tremor (ET) affects approximately 4% of the population above 65 years of age. The traditional view that ET is a familial monosymptomatic disorder with a benign prognosis has recently been challenged, as it is now known to be a progressive and clinically heterogeneous condition with sporadic and familial forms. The pathogenesis of ET is not fully understood, though a disordered central mechanism is the most likely site of origin with possible modulation by muscle adrenoreceptors. The limited post-mortem studies have not shown consistent abnormalities in the brains of ET patients. ET is often misdiagnosed as Parkinson's disease, particularly in the older population. Tremor amplitude increases with age, accounting for substantial disability in older people. Current therapy (drugs and neurosurgery) has significant limitations in older people. A better understanding of its pathophysiology in the future will help in developing more effective therapy, including neuroprotective strategies.