Human botulism studied with single-fiber electromyography

In two cases of mild human botulism, conventional electromyography (EMG) was normal. In one case, the investigation with reptitive nerve stimulation showed slightly abnormal results, but in the other case the findings were within normal limits. Single-fiber EMG showed abnormal neuromuscular function and at later investigations as well, when the patient no longer showed any muscular fatigability. The jitter was frequency dependent and decreased with higher innervation frequency. The single-fiber EMG findings normalized after three months. The results are in agreement with the known disturbance of acetylcholine release.