Discharge rates in electromyography distinguish early between peripheral and central paresis
Article first published online: 13 SEP 2012
Copyright © 2012 Wiley Periodicals, Inc.
Muscle & Nerve
Volume 46, Issue 4, pages 591–593, October 2012
How to Cite
Jürgens, T. P., Puchner, C. and Schulte-Mattler, W. J. (2012), Discharge rates in electromyography distinguish early between peripheral and central paresis. Muscle Nerve, 46: 591–593. doi: 10.1002/mus.23453
- Issue published online: 13 SEP 2012
- Article first published online: 13 SEP 2012
- Accepted manuscript online: 7 MAY 2012 06:57AM EST
- Manuscript Accepted: 1 MAY 2012
- discharge rate;
- firing rate;
- peripheral nerve lesion
Abnormally increased discharge rates (DRs) of motor unit potentials on concentric needle electromyography (CNEMG) indicate a loss of motor units in peripheral neurogenic lesions.
To determine when increased DRs occur during the course of a peripheral nerve lesion, we retrospectively analyzed CNEMG recordings of 19 patients with acute weakness of peripheral origin.
The initial CNEMG studies took place from 3.7 hours to 10 days after the onset of the lesion. Abnormally increased DRs (≥20/s) were found in all but 1 of the muscles in which MRC grade was <4. Peripheral neurogenic damage was confirmed in all patients thereafter. The DRs depended on neither the kind of lesion nor the time between onset and CNEMG examination.
The measurement of DRs of motor unit potentials is helpful immediately after a sudden paresis of MRC grade 3 or worse to differentiate between a central and a peripheral lesion. Muscle Nerve 46: 596–598, 2012