Neural and muscular lesion may result in a reduced number of normal Motor Unit Action Potentials (MUAPs) and a reduced recruitment during volitional activity. Recruitment is deﬁned as the activation of motor units with increasing strength of voluntary muscle contraction. It reﬂects the number of MUAPs identiﬁable during increasing activation when performing tasks like voicing.
Maximal activation of the muscle should be recorded and graded as following:
1. No Activity
2. Single Fibre Pattern
Neural and muscular lesion may result in a reduced recruitment during volitional activity. If only five or less MUAPs are detected on the LEMG-monitor, the pattern is called a single fibre pattern.
3. Strongly Decreased Recruitment Pattern
4. Mildly Decreased Recruitment Pattern