Essential Tremor | Dystonia | Tardive Movement Disorders | Chorea | Tics | Myoclonus | Hemifacial Spasm | Psychogenic Movement Disorders | Restless Legs Syndrome
Tremor consists of rhythmic oscillations across a joint resulting
from involuntary, alternating activation of agonist and antagonist
muscles. For example, wrist tremor is caused by alternating activation
and relaxation of forearm flexor and extensor muscles. Essential
tremor (ET) is the most prevalent movement disorder among adults,
affecting up to 2% of the general population. The prevalence
of ET increases with age; estimates range up to more than 10% in
individuals older than age 70 years. Also called benign essential
tremor and familial tremor, ET may not be benign and can result
in severe impairment in activities of daily living in some individuals.
ET manifests as postural and kinetic tremor at the arms and hands;
the head and voice are often involved (Benito-Leon and Louis 2007; Jankovic 2000).