Correlation of electromyogram and muscle biopsy in myopathy of young age

Objective: To investigate the accuracy of electromyogram (EMG) compared to muscle biopsy in young myopathic patients.

Design: Observational study.

Setting: A university rehabilitation hospital.

Participants: Cases (N=62) were included if the patient was 18 years or younger, and if data were available from muscle biopsy, EMG, and final clinical diagnosis.

Intervention: No intervention.

Main outcome measure: Sensitivity of EMG.

Results: EMG showed myopathic findings in 55 patients, and microscopy revealed myopathy in 50 patients and nonspecific findings in 5 patients. Twenty-eight out of 33 patients showed myogenic EMG findings with a conventional EMG, and histology revealed myopathy in 24 patients. In comparison, turns/amplitude analysis (TAA) with a conventional EMG detected myogenic findings in 27 of 29 patients. Twenty-six of these 27 patients showed myogenic findings in the biopsy.

Conclusions: We concluded that EMG is useful for the detection of myopathy in young patients. In addition, TAA may be helpful in cases of no definite conventional EMG findings and less cooperative patients.