Motor unit number index (MUNIX) in myopathic disorders: Clinical correlations and potential pitfalls

Publication date: Available online 19 July 2019Source: Neurophysiologie CliniqueAuthor(s): Manoel Wilkley Gomes de Sousa, Marcio Luiz Escorcio-Bezerra, Wladimir Bocca Vieira Rezende Pinto, Paulo Victor Sgobbi Souza, Nadia Iandoli de Oliveira Braga, Acary Souza Bulle Oliveira, Gilberto Mastrocola ManzanoSummaryOur 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.
Source: Neurophysiologie Clinique - Category: Neuroscience Source Type: research