New methods of estimating the number of motor units in a muscle.

Two electrophysiological methods have been described for estimating the number of motor units (MU) in a muscle. The methods are based on the original methods of Mc Comas and others, which involve dividing the maximum compound potential (MCP) of muscle evoked by supramaximal electrical stimulation of nerve by a mean motor unit potential (MMUP). The important modifications in the methods are the incorporation of the fluctuations in the response …