Tremor

Tremor is a rhythmic oscillatory movement of a body part caused by alternating contractions of muscle agonists and antagonists. It is the most common extrapyramidal symptom.

Types of tremor

 * Resting – Parkinson's disease, Parkinson's syndrome, essential tremor, cerebellar tremor.
 * Static, postural – physiological tremor in cold, hunger, emotion and exhaustion, essential tremor, Wilson's disease.
 * Kinetic - lesions of the cerebellum and its pathways, essential tremor, psychogenic (hysterical) tremor.
 * Intentional - in cerebellar syndrome, present ataxia and hypermetria.

Tremor is characterized by frequency, amplitude, symmetry, body localization, provocative and suppressive factors, and reactivity to pharmaceuticals.

Different types of tremor form in different regions of the central or peripheral nervous system. The centre of formation is the so-called oscillator (source of rhythmic activity).

Differential diagnosis
Rhythmic myoclonus, asterixis (flapping tremor) - can be distinguished by EMG.

Related articles

 * Extrapyramidal syndromes
 * Hypokinetic extrapyramidal syndromes