The less severe form has a good prognosis and is indicated by episodes occurring primarily at night, and can often be related to migraines. There is no neurological impairment in this form of AH.
The severe form is indicated by the usual paralysis, mental impairment, gait and balance impairment, excessive sweating, and changes in body temperature. Seizures can also be present.
Drug therapy includes flunarizine, a calcium channel blocker.