In December 2002, the International Classification of Headache Disorders 2nd edition (ICHD) replaced what was previously referred to as the I.H.S. criteria for diagnosing headaches.

A much less common type of migraine is migraine with aura. Aura is a temporary neurological symptom that can referred to a focal area of the brain. The most common auras are:

1. unilateral visual symptoms, most usually geometric shapes that slowly expand and move
2. one sided numbness or abnormal sensation that travels
3. one sided weakness
4. speech difficulty

The I.H.S. definition for migraine with aura or classic migraine is:

1. At least 2 attacks fulfilling B.
2. At least 3 of the following 4 characteristics:
1. One or more fully reversible aura symptoms indicating focal cerebral cortical and/or brain stem dysfunction.
2. At least one aura symptom develops gradually over more than 4 minutes, or 2 or more symptoms occur in succession
3. No aura symptoms last for more than 60 minutes, or if more than one aura symptom is present, each aura symptoms cannot last more than 60 minutes.
4. Headaches, which may precede or begin with the aura, most follow within 60 minutes after the aura ends.
3. No other diagnosis to explain the headache symptom.

Probable Migraine or I.H.S. Migrainous Headache