Quantitative analysis of abnormal spontaneous activities, motor unit action potentials and interference patterns were recorded in 55 subjects with traumatic peripheral nerve injury to understand the changes of electromyographic signals.

We analyzed amplitudes of fibrillation potentials and positive sharp waves at rest, amplitude, duration, spike duration and polyphasicity of motor unit action potentials at minimal contraction, and the root mean square(RMS), and mean rectified voltage (MRV) at maximal contraction.

The amplitudes of fibrillation potentials and positive sharp waves had negative correlations with the duration of peripheral nerve injury but the amplitudes of motor unit action potentials, RMS, and MRV had positive correlations.

Therefore electromyographic evaluation could be used for the estimation of the duration of peripheral nerve injury.