Locked-in syndrome is a rare syndrome characterized by quadriplegia, intact consciousness, mutism, and communication using vertical eye movements. We report the case history of a patient with transient locked-in syndrome following repeated shunt procedures for idiopathic aqueductal stenosis. Communication was with lateral eye movements. Although she eventually recovered and regained functional independence, high doses of phenobarbital, given to prevent seizures, sedated her and obscured her mental status during her rehabilitation. We urge the careful monitoring of all centrally acting agents in patients with locked-in syndrome.