What Is a Hemiplegic Migraine?


A hemiplegic migraine is a rare, serious type of migraine headache. The term “hemiplegia” refers to paralysis on one side of the body, which is a temporary symptom of a hemiplegic migraine. The symptoms of a hemiplegic migraine can mimic a stroke.


Hemiplegic migraines are categorized into two types:

  • Familial hemiplegic migraines (FHM) — At least one other family member has the condition
  • Sporadic hemiplegic migraines (SHM) —No known family history of the condition


The main feature of a hemiplegic migraine is an aura that involves numbness, weakness or paralysis on one side of the body. Possible additional symptoms include the following:

  • Dizziness
  • Loss of balance
  • Nausea or vomiting
  • Visual disturbances, such as seeing wavy lines or spots
  • Language difficulties
  • Slurred speech
  • Confusion or memory loss
  • Loss of consciousness

Auras are the hallmark of hemiplegic migraines and are typically more severe and last longer than with other types of migraines. They can last for hours before slowly resolving. Most symptoms go away completely within a few days; however, difficulties with concentration and memory loss can last from weeks to months.

Typically, migraine headache pain, which is throbbing pain on one or both sides of the head, occurs after the aura phase; however, it can also occur before or with the aura. With some hemiplegic migraines, headache pain may not develop. Symptoms can vary from one hemiplegic migraine to the next.


Familial hemiplegic migraines may be caused by abnormal variations in three different genes: CACNA1A, ATP1A2, or SCN1A. A variation of the PRRT2 gene may also cause FHM, but this theory is still controversial in the medical community. These gene variations affect the production of a protein that plays a role in how ions cross the channel that connects nerve cells, affecting the regulation of brain activity.

Sporadic hemiplegic migraines may be caused by variations in the same genes as familial hemiplegic migraines; however, individuals with SHM are typically the first in their family to have the variation. It is also possible to inherit hemiplegic migraines from a parent who is asymptomatic.

For more information about the causes of hemipelgic migraines, visit the National Organization for Rare Disorders’ website at


Like other migraines, a hemiplegic migraine attack can be triggered by certain environmental or lifestyle factors. Triggers may include the following:

  • Stress or intense emotions
  • Bright lights
  • Too much or too little sleep

Risk factors

Individuals with a family history of hemiplegic migraines are most at risk of developing the condition. A child has a 50% chance of developing hemoplegic migraines if one parent has experienced them. Hemiplegic migraines often begin in childhood or adolescence and may cease during adulthood.