Electrophysiological studies of a child with presumed botulism.

Electrophysiological studies of a child with presumed botulism showed that the amplitude of the serially and electrically elicited blink reflexes Rl, R2 and R2' was reduced during recovery. These findings suggest a conduction block of the facial nerves. Other nerve conduction studies and an incremental response to repetitive stimulation demonstrated a block of the presynaptic neuromuscular transmission. Results of the biological tests were negative, but those of electrodiagnosis and clinical examination favored a diagnosis of botulism. A combination of electrically elicited blink reflexes and rapid repetitive stimulation of the peripheral nerves was found to be a sensitive method of assessing the integrity of neuromuscular junctions and the subclinical impairment of muscle nerves.