Visual fields are normal to confrontation. He has slight right ptosis, and the right pupil is smaller than the left, the asymmetry being especially noticeable in dim light. Extraocular movements are full, but there is horizontal nystagmus with the fast component to the left. Sensation to pin and temperature are diminished on the right side of the face. Facial movement and strength are symmetrical.
Hearing is intact.
Cranial nerves XI and XII are normal. Tendon reflexes are symmetric and there are no pathological reflexes. Pain and temperature are reduced over the left limbs and trunk, but not the left face. A CT scan of the head without contrast is normal. You admit him to the hospital, ordering routine laboratory studies and a regular diet.