Long-term measurement of tremor.
To account for the fluctuating and context-dependent nature of tremor, the method of ambulatory long-term electromyography (EMG) was developed for quantification of this symptom. It is based on successive evaluation of 15-s intervals by using a fast Fourier transformation (FFT). The standard results obtained are (a) tremor occurrence, a measure of how many intervals contain tremor; (b) mean tremor intensity; and (v) mean tremor frequency. This new method fulfills the so-called "test criteria" such as reliability, validity, sensitivity, and specificity for tremor quantification in essential tremor (ET) and Parkinson's disease (PD). In addition, we developed a method of determining the antagonist activation pattern by using cross-correlation analysis, also based on the long-term approach. This allows differentiation between ET and PD with a high sensitivity and a high interrater reliability. We conclude that long-term EMG is useful for both quantification and differentiation of tremor.
Spieker
S
S
Department of Neurology, University of Tübingen, Germany.
Boose
A
A
Breit
S
S
Dichgans
J
J
D003937:Diagnosis, Differential; D004576:Electromyography; D005583:Fourier Analysis; D006801:Humans; D010300:Parkinson Disease / Q000175:diagnosis; D013997:Time Factors; D014202:Tremor / Q000175:diagnosis*