Ivan is a 68 year old man who has enjoyed excellent health in the past. His only medication is hydrochlorothiazide for mild hypertension. For the past few weeks he noticed that by the end of the day he had difficulty focusing his eyes and keeping them open. He decided to see his family physician when the other day his vision became double. On the day of the visit, Ivan was feeling even worse. His double vision was present shortly after lunch and he felt generally weak. On observation, it was clear that Ivan had a right-sided ptosis. He kept closing one eye and then the other, complaining that otherwise his vision was double. His voice seemed mildly hoarse. Blood pressure was normal at 135/80. General physical examination of the heart, lungs, and abdomen was normal. Neurological examination showed that the pupils were equal and reactive. A prominent ptosis was present on the right. The extra ocular movements were abnormal with dysconjugate gaze present intermittently and not consistently on lateral, upward, and downward gaze. The other cranial nerves were normal. Tone was normal in the limbs. He had some difficulty holding up his arms in the air for more than a couple of minutes. He had some difficulty doing more that 5 deep knee bends. Sensation was normal and the reflexes were all present and symmetric. The plantar responses were down going. You ask Ivan to close his eyes and rest them for a few minutes while you make some notes. You ask him then to open his eyes and temporarily the double vision is much better and the ptosis is almost gone! A referral is made to the neurologist on call. She asks that you send Ivan to the emergency room so that she can perform a tensilon test to confirm the diagnosis.