Search

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.

Objective: 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., Methods: 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., Results: 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., Conclusions: 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)., Significance: Irregular MUPs in EDMD most probably reflect increased variability of the muscle fiber size.

Various laboratory tests were performed to establish carriership in 24 familial and sporadic carriers of Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD). The activity of creatine kinase was in all females but one, very high and significantly higher in isolated carriers; quantitative EMG indicated myopathic changes, muscle biopsies revealed different degrees of changes--from a variability of muscle fibers size and central nuclei to severe dystrophic features. Immunohistochemical evaluation of dystrophin revealed, in all females but one, mosaic pattern of staining--a mixture of dystrophin-positive and dystrophin-negative fibers, the latter consist 15-30% of all fibers. Quantitative evaluation of dystrophin showed a reduced abundance with normal or abnormal molecular weight. The abnormalities were more expressed in sporadic cases. The detection of sporadic carriers, particularly the non-manifesting clinical, is a very important progress--it permits the correct diagnosis (before, these females were diagnosed as limb girdle muscle dystrophy (LGMD) and supply them with the benefit of genetic counselling, which also requires some modification.