The care of the elderly physicians from another hospital asked us to take over the management of an 87-year-old man who lived alone. Other than osteoarthritis mainly affecting his left knee, surgery for prostatic hypertrophy four years earlier, a reducible right inguinal hernia and moderately high alcohol consumption, he had no significant medical history. He had smoked 15 cigarettes a day for many years. Remarkably, he had only used senna for occasional constipation and paracetamol for joint pain in the preceding few years. He did the Scotsman cryptic crossword daily.

He had attended the elderly care out-patient clinic about 10 weeks before admission complaining of poor balance and new onset of falling. He attributed the falls to tripping rather than poor balance, and had no associated loss of consciousness. Three weeks before his transfer to neurology, he had been admitted to the elderly care ward following a night-time fall. He had become tangled in his duvet and fallen to the floor where he remained, unable to get up, until morning when a neighbour found him. He had not lost consciousness or experienced other symptoms prior to or during the fall, and he could not recall hitting his head. He felt that poor balance, stiff legs, and a recent onset (3–4 weeks) of double vision caused the fall.

On examination at the time, his Mini-Mental State Examination score was 20 out of 30 and he had a right VI nerve palsy. The physicians thought his left leg was slightly weaker than the right, but found it difficult to be sure because of his knee pain. His reflexes were all normal and his plantar responses were flexor. The remainder of his examination was normal.

He had a normal full blood …