CLINICAL NEUROPHYSIOLOGY OF TREMOR

The neurophysiological analysis of tremor has a long tradition. These attempts were directed to understand the mechanisms underlying tremor, on the one hand, and to develop tools to better diagnose the differen t types of tremor, on the other. Meanwhile, reasonable criteria are av ailable to distinguish between centrally and peripherally mediated tre mors. However, no generally accepted means exist to differentiate the different forms of central tremors. Frequency is a useful classifier f or cerebellar tremor, rubral tremor, and orthostatic tremor. Although the highest amplitudes are found in Parkinson's disease, this paramete r does not well distinguish between the different tremors. Waveform an alysis of tremor is a promising tool to separate between the different tremors. Polymyography is pathognomonic for some rare forms of tremor . New approaches to classify tremors are based on positron emission to mography scanning, analysis of ballistic movement, and reflex testing. The means to separate myoclonias from tremors include EEG/EMG correla tion techniques, long-latency reflexes, and polymyography. Provided th ese techniques are applied in the setting of careful clinical analysis of tremor syndromes, they may prove to be helpful in clinical practic e.