A 60-year-old man reported slowly progressive symptoms over a period of five years. He experienced tingling in his toes that gradually spread halfway up the lower legs. He also developed a stiff feeling in his lower legs and nightly cramps in both calves, but no pain. For one year, he complained of numb fingertips with some loss of dexterity. He had no symptoms of autonomic dysfunction, was not known to have diabetes, ate a healthy, balanced diet, drank one glass of alcohol a day, and had not been treated with neurotoxic medication. His family history indicated no other relatives with similar complaints.