Rhythmic, unintentional, rapidly alternating flexion and extension of opposing muscles in one or more parts of the body, often the hand or jaw.
Example: A teacher’s extended right hand shakes. Her writing has become illegible, and her symptoms worsen when she drinks coffee.
Grinnell, R. (2008). Tremor. Psych Central. Retrieved on September 1, 2015, from http://psychcentral.com/encyclopedia/2008/tremor/