She remains mentally alert. She exhibits no seizure activity. A gastrocnemius biopsy shows grouped atrophy. For several years, a 55 year old male has fatigued easily as the day progresses, but after a night's rest feels better in the morning. At first, he noted that his eyelids drooped, but now he has difficulty chewing food, particularly meat.
Physical examination reveals reduced strength in both right and left extremities.
Deep tendon reflexes are normal. A biopsy of muscle reveals no major histologic abnormalities. At first, he had difficulty climbing stairs. Two years later he was confined to a wheelchair. Another two years passed and he could no longer feed himself.