Alternating hemiplegia is a rare neurological disorder that develops in childhood, usually before the first 4 years. The disorder is characterized by recurrent but temporary episodes of paralysis on one side of the body. The paralysis can affect eye movements, limbs, or facial muscles. Other symptoms may include mental impairment, balance and gait difficulties, excessive sweating, and changes in body temperature. Seizures can occur.
Sleep helps in the recovery from the periods of paralysis but the paralysis can recur upon waking.
The cause of the disorder is unknown. Drug therapy including flunarizine may help to reduce the severity and duration of attacks of paralysis associated with alternating hemiplegia. Generally, children with alternating hemiplegia have a poor prognosis because intellectual and mental capacity do not respond to drug therapy, and balance and gait problems continue. Over time, walking unassisted becomes difficult or impossible. This fact sheet is in the public domain.