Limb girdle muscular dystrophy: a quantitative electromyographic study.

BACKGROUND

Quantitative electromyography (EMG) using different needle techniques has not been performed on a large limb girdle muscular dystrophy (LGMD) group.

PURPOSE

To establish statistically: (1) correlations between clinical features (patient age, disease duration, degree of weakness) and quantitative needle EMG; (2) correlations between different needle EMG parameters, and (3) differences in quantitative EMG comparing patients with a healthy control group.

METHODS

Nerve conduction studies and needle EMG (motorunit analysis, MacroEMG, SFEMG) were performed on Mm. triceps brachii and tibialis anterior according to standard techniques on 20 LGMD patients.

RESULTS

Nerve conduction studies were essentially normal. Motorunit analysis and MacroEMG parameters correlated with various clinical features. SFEMG results did not correlate with either clinical measures or other needle EMG findings. There was a significant difference between patients and controls in motorunit analysis and MacroEMG results.

CONCLUSION

(1) Progressive weakness correlated with concentric needle and MacroEMG indicators of progressive muscle fibre degeneration and loss. (2) SFEMG showed that muscle fibre reinnervation followed a course independent of fibre degeneration, and measured clinical features.