Electrophysiological estimation of the number of motor units within a human muscle

Assessment of Motor Units in Neuromuscular Disease

“…Most of the electrophysiology methods have studied the thenar and hypothenar muscles supplied by the median or ulnar nerves, and, to a lesser extent, the extensor digitorum brevis or tibialis anterior muscles supplied by the peroneal nerve, although there are many small studies of other nerve, muscle combinations. More than 7 MUNE methods have been published [35][36][37][38][39][40][41][42]. These can be divided into 3 groups: 1) methods developed >15 years ago where the methodology has been validated but the method is relatively inactive or used in few centers; 2) active methods that are used in multiple centers with validated methodology; 3) active methods that are used in few centers/research centers and the methodology requires further validation.…”

Motor unit number estimation of the tibialis anterior muscle in spinal cord injury

“…6 For diseases affecting the anterior horn cells, especially the amyotrophic lateral sclerosis, MUNE is believed to be the most sensitive follow-up tool for the evaluation of disease progression. 7 Since McComas's first proposal, 5 various other MUNE methods have been developed and validated. The adapted multiple point stimulation (AMPS) method has several advantages.…”

“…AMPS was also proven to be reliable and reproducible, as it minimizes alternation and motor unit (MU) selection bias in estimating thenar MU size and number. 8 The AMPS method combines important elements of the original McComas's technique 5 with the multiple stimulation method, as it can analyze two to three surface-recorded MU action potentials (S-MUAP) obtained in response to incremental stimulation at different points. Eric Albrecht and Thierry Kuntzer 9 confirmed the validity of the method in the lower extremity in healthy subjects and in patients with amyotrophic lateral sclerosis or acquired peripheral neuropathies.…”

An Appraisal of Novel Biomarkers for Evaluating and Monitoring Neurologic Diseases: Editorial Introduction

“…In 1971, McComas et al [9] proposed a method for estimating the number of motor units innervating a muscle being studied; such a method would clearly be of great utility in following disease progression in motor neuron diseases or other axonal injuries. However, issues surrounding inter-rater reliability and validity rendered the original method and subsequent alternatives less useful than originally thought.…”