The diagnostic value of electromyography in infantile hypotonia.

There is controversy over the usefulness of electromyography (EMG) in the examination of hypotonic infants with suspected neuromuscular disease. We compared the initial EMG findings of 51 such children under 1 year of age with their final clinical diagnoses determined by independent means. The EMG predicted the final diagnosis in 82% of infants less than 4 months of age and 85% of those over 4 months of age. Botulism was correctly identified by EMG in nine of 11 cases. The EMG diagnosis was identical to that obtained by muscle biopsy in 64% of cases in which biopsy was done, and diagnosis obtained by the two methods were inconsistent in only 14%. Electromyography is a sensitive and noninvasive diagnostic tool for the diagnosis of neuromuscular disease in infantile hypotonia.