Tremor.

Tremor, defined as a rhythmic and involuntary movement of any body part, is the most prevalent movement disorder, affecting millions of people in the United States. All adults have varying degrees of physiological tremor so it is imperative to distinguish physiological tremor from pathological tremor types. Tremor is not inherently dangerous, but it can cause significant disability at home and in the workplace. Common tremors like essential tremor and Parkinson disease tremor can be recognized by most clinicians at the early stages for the initiation of disease-specific medical therapies. Less common tremors, such as those induced by drugs or brain lesions, are also important to recognize because they may be more refractory to medical therapies and may require earlier referral to a neurological specialist. In patients with the most progressive and severe tremors that are resistant to medical therapies, surgical interventions are available and typically target deep brain regions with stimulation or lesioning. This Grand Rounds review describes the evaluation and evidence-based management of the most common tremors, essential tremor and Parkinson disease tremor.