Methylmercury poisoning, Clinical follow-up and sensory nerve conduction studies.

Methylmercury poisoning occurred in four cases after passage of methylmercury through the food chain. The neurological damage in all four cases was severe. The damage was greater at younger ages with maximum involvement in the case of transplacental poisoning. Significant recovery occurred in two cases, but on six-year follow-up two cases remained severely impaired. Clinical and electrophysiological evidence suggests that damage to peripheral sensory nerves may not be the cause of the late sensory symptomatology.