Relationships between clinical data and quantitative EMG findings in facioscapulohumeral muscular dystrophy.

Małgorzata Gaweł, Klinika Neurologii, ul. Banacha 1A, 02-097 Warszawa, phone: +48 22 599 28 57, fax: +48 22 599 18 57, e-mail: .
Neurologia i neurochirurgia polska (Impact Factor: 0.54). 01/2013; 47(1):8-17. DOI: 10.5114/ninp.2013.32936
Source: PubMed

ABSTRACT Background and purpose: In recently published reports, electrophysiological findings were analysed, in some facioscapulo-humeral muscular dystrophy (FSHD) cases without genetic disease confirmation. In several reports, some electrophysiological findings were described, not specific for myopathy. The aim of study was to analyse electrophysiological findings in a genetically homogeneous FSHD group to find possible relationships between electromyography (EMG) abnormalities and clinical symptoms. Material and methods: 37 patients with genetically proven FSHD (23 men and 14 women) aged 7-58 years (mean 28.8 years) were studied. Electromyographic examinations were done according to a uniform scheme for FSHD. Quantitative EMG examination was performed in vastus lateralis, tibialis anterior, deltoid and biceps brachii muscles. Results: There was no correlation between clinical features and electrophysiological findings. EMG confirmed myopathic changes in all patients with most advanced changes in tibialis anterior and deltoid muscles. Some of these changes were unspecific for myopathy and the degree of their intensity differed in particular muscles. The most advanced changes were observed in the tibialis anterior and deltoid muscles. The usefulness of the size index for myopathic processes assessment was confirmed. Analysis of so-called outliers for motor unit activity potential parameters did not show any new data for evaluation of the myopathic process. Myopathic changes in our material were not as advanced as those described in classical dystrophies. Histopathological examinations of skeletal muscle were normal in about 1/3 of patients. Conclusions: We established that myopathic changes are clearly present in FSHD, with different degrees of intensity, most pronounced in tibialis anterior and deltoid muscles. There was no correlation between electrophysiological findings and clinical features. The size index provided the highest motor unit potential diagnostic sensitivity in FSHD.

  • [Show abstract] [Hide abstract]
    ABSTRACT: The aim of this study was to compare the effectiveness of quantities such as amplitude, duration, area, size index, number of peaks and irregularity coefficient applied to the classification of motor unit action potentials (MUAPs) in neuromuscular disorders. We have analyzed 215 potentials recorded from 20 neurogenic patients and 240 potentials recorded from 14 myogenic patients. The statistical values for each parameter and correlation coefficients between parameters have been analyzed. The percentages of potentials unclassified by amplitude, duration, area/amplitude, area and size index were 31, 34, 28, 15 and 15%, respectively. Neither the number of phases and turns nor the irregularity coefficient may be used for the differentiation between neuro- and myogenic groups. There was also a set of MUAPs that were not properly classified by any of the above parameters. Among the unclassified potentials there were more potentials from myogenic cases. These unclassified myogenic MUAPs were predominantly irregular, whereas most of the unclassified neurogenic MUAPs were simple. In neurogenic cases, parameters describing the size of the potential (amplitude, duration, area) were not significantly correlated with those describing the shape (number of phases and turns), whereas in myogenic cases some correlation between these parameters was significant. MUAP quantities, due to the different correlation between them in myogenic and neurogenic disorders, have different sensitivities. Indexes were more sensitive than simple parameters and were also much more effective in the evaluation of atypical potentials.
    Clinical Neurophysiology 09/2000; 111(8):1380-7. · 2.98 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The aim of present study was to analyse the motor unit (MU) changes in progressive muscle dystrophy (PMD) and in inflammatory myopathy (IM) and to evaluate eventual neurogenic factors in MU reorganisation. The material consisted of 20 patients with (PMD), 20 patients with (IM) and 20 healthy age-matched volunteers. The shape of concentric needle motor unit potentials (cn MUPs), including their duration, amplitude, area, size index and number of phases, the interference pattern and the amplitude and area of macro MUPs were evaluated. The cn emg data satisfied the classical criteria for myopathy in all examined patients, at least in one of the tested muscles. A decreased amplitude and/or area of macro MUPs, compatible with myopathy, were observed in 32 of the 40 patients. In some cases of chronic IM and PDM the long duration polyphasic potentials were recorded. The size index (SI) value of long polyphasic MUPs was usually decreased or normal. This feature indicated that desynchronisation of "myopathic" MUPs results from a reduced number of muscle fibers and their degeneration and regeneration. The results indicated no difference in MU reorganization between PMD and IM and no evidence of neurogenic factors in MU changes.
    Electromyography and clinical neurophysiology 01/2000; 40(7):431-9.
  • [Show abstract] [Hide abstract]
    ABSTRACT: The aim of the study was to analyse electromyographic changes in Emery-Dreifuss muscular dystrophy (EDMD) that are atypical for myopathy. Our special interest was focused on high amplitude polyphasic motor unit potentials (MUPs), also termed irregular MUPs. We studied 21 EDMD patients with the diagnosis based on clinical data, DNA analysis and immunohistochemical muscle studies. Rectus femoris muscle biopsies were investigated in all affected patients. Electrophysiological investigations involved quantitative concentric needle electromyography (CNEMG) of biceps brachii (BB) and rectus femoris (RF) muscles. Simulation studies were performed to approximate the number, diameter and distribution of muscle fibers, which contribute to irregular MUPs. The EMG data in EDMD were compatible with myopathy. Irregular MUPs showed longer duration, larger area, size index and higher amplitude then simple ones (P < 0.05). The approximation of features of muscle fibers contributing to irregular MUP also indicated smaller (<45 microm) and larger (>55 microm) diameters than normal (50 +/- 5 microm). Muscle biopsy specimens revealed the variable muscle fiber size due to atrophy, hypertrophy, and muscle fiber splitting. Irregular MUPs recorded in EDMD are due to hypertrophied and atrophied fibers as well as increased fiber density. They reflect reorganization of the motor unit in a slow progression myopathic process (muscle fiber hypertrophy and splitting). Irregular MUPs in EDMD most probably reflect increased variability of the muscle fiber size.
    Clinical Neurophysiology 11/2005; 116(11):2520-7. · 2.98 Impact Factor


Available from
Feb 26, 2015