Hemiplegic migraine

A National Migraine Centre factsheet

Identifying and treating a distressing condition

What is hemiplegic migraine?

Hemiplegic migraine isn’t common, but it can be distressing. It’s characterised as migraine with weakness or paralysis on one side of the body, which can affect the face, arm, leg or all down one side.

This weakness can occur as a part of the aura phase and can last from around half an hour, before the headache begins, through to several days. Occasionally, the headache comes on first.

There are two main types of hemiplegic migraine:

1. Familial Hemiplegic Migraine (FHM)

FHM runs in families, with one or more other family members suffering one-sided weakness during their migraine attacks.

There are currently four genes known to be associated with this type.

Roughly 50 per cent of children with a parent that has hemiplegic migraine will go on to develop this type of migraine.

2. Sporadic Hemiplegic Migraine (SHM)

SHM is where just one person in a family is known to get the one-sided weakness with migraine and is thought to be due to spontaneous mutations of genes. It may also affect someone with a family member who has the genes but who has not been affected.

Genetic testing is not necessary for either type of hemiplegic migraine.

Symptoms of hemiplegic migraine

  • Weakness or paralysis on one side of the body (hemiplegia)
  • Headache
  • Trouble speaking
  • Phonophobia (increased sensitivity to sound) and/or photophobia (increased sensitivity to light)
  • Other typical aura symptoms, such as vision changes (sparkles, shimmers, visual field defects), numbness, tingling
  • Impaired state of consciousness, from mild confusion to profound coma
  • Nausea and/or vomiting
  • Problems with muscle coordination, which can cause walking difficulties

Diagnosing hemiplegic migraine

Speak to a specialist to confirm a diagnosis, through the NHS or the National Migraine Centre. A diagnosis of hemiplegic migraine is based on having at least two attacks that include both of the following:

  • aura accompanied by temporary weakness and temporary sensory and/or speech/language symptoms
  • at least two of the following four characteristics –
    • one or more aura symptom that spreads gradually over more than five minutes, and/or two or more aura symptoms that occur in succession
    • each non-motor (that is, not affecting your movement) aura symptom lasting five minutes to an hour, and motor symptoms lasting more than 72 hours
    • at least one unilateral (one-sided) aura symptom
      the aura being accompanied by headache, or followed by headache within one hour

Attacks often start in childhood and may be alarming. Doctors will understand the patient’s history of symptoms and conduct investigations (including brain scanning when appropriate) to exclude other possible causes. The symptoms may be confused with a tumour, epilepsy or a stroke when they initially occur and these need to be excluded if there is any doubt.


The hemiplegic symptoms may just last for just half an hour or so, but in some cases can persists for several hours, days or, in some rare variants, even weeks.

In two-thirds of people, the symptoms last less than a day. Usually, symptoms will go away altogether between attacks.

This type of migraine can be especially difficult to live with if attacks are frequent.


Hemiplegic migraine can respond to many of the lifestyle, acute treatments and preventative treatments used for any type of migraine, but it is important to get advice from a headache specialist for this more unusual type of migraine.

Book an appointment with the experts: review the best treatment options for hemiplegic migraine with a leading headache specialist. Beat the misery of migraine and get back to living. Book your consultation through the National Migraine Centre now.

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