Distinguishing essential tremor from Parkinson's disease: bedside tests and laboratory evaluations.

Expert Rev Neurother. 2012 Jun;12(6):687-96.

Thenganatt MA, Louis ED.

Source

Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, NY, USA. EDL2@columbia.edu.

Abstract

Distinguishing essential tremor from Parkinson's disease can be challenging, both in the early stages of these diseases and as these diseases progress. Various tremor types (rest, postural, kinetic and intention) may be seen in both essential tremor and Parkinson's disease. Furthermore, with time, the two diseases may coexist within a single patient. Detailed clinical examination with attention to specific features of tremor (frequency, amplitude, pattern and distribution) and associated neurological findings may help distinguish patients with the two diseases. Laboratory testing may provide information that further aids in differentiating the two diseases. These tests include accelerometry and surface electromyography, spiral analysis, dopamine transporter imaging, olfactory testing and, eventually, postmortem histopathology. These tests have limitations and their diagnostic utility requires additional study.