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Overview/Background/Prevalence
• Essential Tremor (ET) is one of the most common movement disorders. It
can occur at any age, but is most common in people age 40 and older where
incidence increases with each decade. ET affects up to 5% of people over
the age of 60.
• Age and family history are the two greatest risk factors for ET.
• ET is typically a slowly progressive condition with patients often having
tremor for many years prior to seeking treatment.
• ET most commonly affects the hands but can affect the head and voice.
Less commonly, the legs, trunk, jaw, and other facial muscles are involved.
• Patients report a beneficial effect of alcohol about 60% of the time.
• Many patients with ET have a family history of tremor (50%+). Despite
this, while a few genes have been associated with ET, genetic testing is not
currently available.
• ET is commonly misdiagnosed, and often confused with Parkinson's disease
(PD) or dystonia.
Table 1. Examination for Essential Tremor
Area Comments
Limbs Typically seen when holding a limb against gravity (arms outstretched,
wing-beating ) or with movement (finger to nose).
These items together are called "action tremor," reflecting the fact that
ET typically occurs during movement and typically affects the upper
extremities.
Head Typically seen as a side to side shaking of the head ("no-no" tremor),
but can occur in an up and down motion ("yes-yes") or can be mixed.
Voice The voice is evaluated by listening to speech but also by having the
patient hold a prolonged "ahhh" or "eee."
Facial Muscles Examined by having the patient purse the lips or squeeze the eyelids.
Tasks Patient can be observed during functional tasks such as writing,
drawing, pouring water, drinking from a cup.
Assessment/Screening
