Table 1.

Differential diagnosis of common types of tremor.

CHARACTERISTICS	ESSENTIAL TREMOR	PARKINSON’S DISEASE	CEREBELLAR TREMOR	DRUG-INDUCED TREMOR	PSYCHOGENIC TREMOR
Arm position	Postural and kinetic tremor, rest tremor in advanced ET	Rest tremor, postural and kinetic in some patients	Kinetic tremor Postural tremor in some patients	Postural and kinetic tremor	Variable
Affected body parts	Arms, legs, neck, vocal cords	Arms, legs, chin	Arms, legs infrequently, neck	Arms, other body segments may be affected in severe cases	Variable
Frequency	5–10 Hz	3–5 Hz	2–7 Hz	5–12 Hz	2–12 Hz
Amplitude	Small in early stages, increases with progression (and lower frequency)	Small to moderate	Moderate to large	Small to moderate	Variable
Symmetry	Typically bilateral, symmetric, about 10% unilateral tremor	Asymmetric onset typical, asymmetry is commonly preserved in bilateral disease	Bilateral in degenerative ataxias, unilateral in acquired ataxias (stroke, multiple sclerosis)	Bilateral and symmetric	Variable
Associated neurologic signs	Subtle midline cerebellar signs May coexist with focal dystonia	Rigidity, bradykinesia, postural instability	Ataxia, oculomotor abnormalities, dysarthria	Typically absent	Variable
Additional features	Rest tremor persist during walking	Symptoms are responsive to dopaminergic therapy	Intention tremor Pyramidal and extrapyramidal features may be present in neurodegenerative ataxias	Drug-induced parkinsonism in antidopaminergic agents	Abrupt onset, distractibility, irregular, inconsistent, suggestibility, entrainment