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Updated: Jan 21, 2026

Electrophysiological Motor Unit Number Estimation MUNE Measuring Compound Muscle Action Potential CMAP in Mouse Hindlimb Muscles
Published on: September 25, 2015
Motor unit number index (MUNIX) in myopathic disorders: Clinical correlations and potential pitfalls
Manoel Wilkley Gomes de Sousa1, Marcio Luiz Escorcio-Bezerra1, Wladimir Bocca Vieira Rezende Pinto1
1Department of Neurology, Universidade Federal de São-Paulo, São-Paulo, Brazil.
Abstract:
Our aim was to study motor unit number index (MUNIX) in myopathic disorders. We studied 11 patients with myopathy, and healthy controls. We obtained MUNIX, compound muscle action potential (CMAP), motor unit size index (MUSIX) and alpha (α, power exponent from MUNIX equation) measurements from three different muscles. MUNIX and CMAP were significantly lower in one muscle. This MUNIX decrease may not be related to motor neuron loss, but rather to muscle fiber atrophy. MUSIX and α did not change and may be useful in determining whether the MUNIX decrease is indeed due to motor unit loss.
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