Table 2

 Features differentiating tremor of PD from ET72

FeaturesParkinson’s tremorEssential tremor
TremorAt rest, increases with walking.Posture holding or action
Decreases with posture holding or action
Frequency3–6 Hz5–12 Hz
DistributionAsymmetricalSymmetrical (mostly)
Body partsHands and legsHands, head, voice
WritingMicrographiaTremulous
CourseProgressiveStable or slowly progressive
Family historyLess common (1%)Often (30%–50%)
Other neurological signsBradykinesia, rigidity, loss of postural reflexesNone
Substances that improve tremorLevodopa, anticholinergicsAlcohol, propranolol, primidone
Surgical treatmentPatients usually have other parkinsonian features, requiring subthalamic nucleus or internal globus pallidus deep brain stimulation (DBS)Thalamic VIM DBS or thalamotomy