Table 3.

Clinical criteria for ET and differential diagnosis for a patient with middle frequency postural tremor.

Clinical criteria for ET (MDS consensus statement Deuschl et al., 1998):	Differential diagnosis middle frequency postural tremor:
Inclusion criteria	Essential tremor
Bilateral, largely symmetric postural, or kinetic tremor involving hands and forearms that is visible and persistent	Parkinson’s disease
Additional or isolated tremor in head but absence of abnormal posturing	Enhanced physiologic tremor
Exclusion criteria	Dystonic tremor
Other abnormal neurological signs (especially dystonia)	Wilson disease
Presence of known causes of enhanced physiologic tremor	Primary writing tremor
Historical or clinical evidence of psychogenic tremor	Epilepsia partialis continua
Convincing evidence of sudden onset or step-wise deterioration	Familial cortical tremor
Primary orthostatic tremor	Spinal segmental myoclonus
Isolated voice, tongue, chin, leg tremor	Progressive myoclonic ataxia
Isolated position- or task-specific tremor	Spinocerebellar ataxias
	Neuropathic tremor
	Drug-induced tremor
	Metabolic alterations
	Fragile-X-associated tremor/ataxia syndrome (FXTAS)