open access

Vol 49, No 4 (2015)
Original research articles
Submitted: 2014-05-19
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Motor unit reorganization in progressive muscular dystrophies and congenital myopathies

Elżbieta Szmidt-Sałkowska, Małgorzata Gaweł, Marta Lipowska
DOI: 10.1016/j.pjnns.2015.05.005
·
Neurol Neurochir Pol 2015;49(4):223-228.

open access

Vol 49, No 4 (2015)
Original research articles
Submitted: 2014-05-19

Abstract

The aim of this study was to analyze motor unit reorganization in different types of progressive muscular dystrophies and congenital myopathies.

The study population consisted of patients with genetically verified progressive muscular dystrophies: Duchenne (DMD) (n=54), Becker (BMD) (n=30), facio-scapulo-humeral (FSHD) (n=37), and Emery–Dreifuss (E-DD) (n=26). Patients with probable limb-girdle dystrophy (L-GD) (n=58) and congenital myopathies (n=35) were also included in the study. Quantitative EMG recordings were obtained from 469 muscles. Muscle activity at rest and during slight voluntary and maximal muscle contraction was analyzed. The motor unit activity potential (MUAP) duration, amplitude, area, size index (SI), polyphasicity, and the presence of “outliers” were evaluated.

Diminished values of MUAP parameters and decreased maximal amplitude of maximal muscle contraction were recorded most frequently in DMD and mainly in the biceps brachii muscles. SI was the most frequently changed EMG parameter. “Outliers” with amplitude below the normal range were recorded more frequently then a decreased mean MUAP amplitude (what could indicate a very high sensitivity of this EMG parameter). Pathological interference pattern was recorded in 34.7% of biceps brachii and in 21.2% of rectus femoris muscles. In FSHD, decreased MUAP duration and SI and pathological interference pattern with low amplitude were recorded most frequently in the tibial anterior and deltoid muscles.

The presence of potentials with reduced parameters is a result of decreasing motor unit area (reduced number and size of muscle fibers), while high amplitude potentials recorded in BMD and E-DD could indicate a slow and mild course of disease and muscle regeneration.

Abstract

The aim of this study was to analyze motor unit reorganization in different types of progressive muscular dystrophies and congenital myopathies.

The study population consisted of patients with genetically verified progressive muscular dystrophies: Duchenne (DMD) (n=54), Becker (BMD) (n=30), facio-scapulo-humeral (FSHD) (n=37), and Emery–Dreifuss (E-DD) (n=26). Patients with probable limb-girdle dystrophy (L-GD) (n=58) and congenital myopathies (n=35) were also included in the study. Quantitative EMG recordings were obtained from 469 muscles. Muscle activity at rest and during slight voluntary and maximal muscle contraction was analyzed. The motor unit activity potential (MUAP) duration, amplitude, area, size index (SI), polyphasicity, and the presence of “outliers” were evaluated.

Diminished values of MUAP parameters and decreased maximal amplitude of maximal muscle contraction were recorded most frequently in DMD and mainly in the biceps brachii muscles. SI was the most frequently changed EMG parameter. “Outliers” with amplitude below the normal range were recorded more frequently then a decreased mean MUAP amplitude (what could indicate a very high sensitivity of this EMG parameter). Pathological interference pattern was recorded in 34.7% of biceps brachii and in 21.2% of rectus femoris muscles. In FSHD, decreased MUAP duration and SI and pathological interference pattern with low amplitude were recorded most frequently in the tibial anterior and deltoid muscles.

The presence of potentials with reduced parameters is a result of decreasing motor unit area (reduced number and size of muscle fibers), while high amplitude potentials recorded in BMD and E-DD could indicate a slow and mild course of disease and muscle regeneration.

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Keywords

Electromyography, Progressive muscular dystrophy, Congenital myopathy

About this article
Title

Motor unit reorganization in progressive muscular dystrophies and congenital myopathies

Journal

Neurologia i Neurochirurgia Polska

Issue

Vol 49, No 4 (2015)

Pages

223-228

DOI

10.1016/j.pjnns.2015.05.005

Bibliographic record

Neurol Neurochir Pol 2015;49(4):223-228.

Keywords

Electromyography
Progressive muscular dystrophy
Congenital myopathy

Authors

Elżbieta Szmidt-Sałkowska
Małgorzata Gaweł
Marta Lipowska

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