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

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.

Single Fibre Pattern

3. Strongly Decreased Recruitment Pattern

Strongly Decreased Recruitment Pattern

4. Mildly Decreased Recruitment Pattern

Mildly Decreased Recruitment Pattern

5. Normal/Dense Recruitment Pattern

Dense Recruitment Pattern