Table 2.

Common Types of Tremor

Type	Characteristics
Rest tremor (tremor at rest)	Tremor in a body part that is not voluntarily activated and is completely supported against gravity (includes reemerging tremor, see text).
Action tremor	Any tremor that is produced by voluntary contraction of muscle
Postural tremor	Tremor that is present while voluntarily maintaining a position against gravity. Rarely, the tremor may specifically occur in certain positions, but not in others (position-specific tremor).
Kinetic tremor	Tremor that occurs during any voluntary movement
Unspecified kinetic tremor	During nongoal-directed movements
Intention tremor	During goal-directed movements
Task-specific kinetic tremor	Appears only, or becomes markedly exacerbated, during specific activities
Isometric tremor	Occurs as a result of muscle contraction against a rigid stationary object

Adapted from Bhidayasiri R. Differential diagnosis of common tremor syndromes. Postgrad Med J 2005;81(962):756–762, with permission from BMJ Publishing Group Ltd.