Chapter

Myoclonus Studies

Jay A. Liveson and Dong M. Ma

in Laboratory Reference for Clinical Neurophysiology

Published in print May 1999 | ISBN: 9780195129243
Published online March 2012 | e-ISBN: 9780199847792 | DOI: http://dx.doi.org/10.1093/acprof:oso/9780195129243.003.0022
Myoclonus Studies

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Mycolonus is a sudden, irregular, jerky movement of a group of muscles. It can be related to hyperexcitability of cerebral neurons, manifested by periodic synchronous EEG discharges (PSDs). If these are cortical, the relationship can be studied using several techniques. The most basic is polygraph recording of both electroencephalogram (EEG) and electromyogram (EMG) events to study any temporal relationship between cortical discharges and muscle movement. In some forms (such as cortical reflex myoclonus), routine somatosensory evoked potential studies can produce giant responses. There are more specialized methods to characterize the temporal relationship between cortical and myoclonic events. One is jerk-locked averaging. Another is jerk-locked evoked potentials. In addition, long-latency reflexes can be recorded. These require specialized arrangements including a triggering device and a backward averaging program (opisthotonic) that permits studying the period preceding the triggering event.

Keywords: mycolonus; hyperexcitability; polygraph recording; myoclonic events; long-latency reflexes; backward averaging program; jerk-locked averaging; jerk-locked evoked potentials

Chapter.  656 words.  Illustrated.

Subjects: Neuroscience

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