Migraine Aura

When sensory aura accompanies visual aura, it tends to follow visual aura within minutes. This aura typically begins as unilateral paresthesias in a limb or one side of the face. From their origin, the paresthesias may gradually march down the limb or face, often with a subsequent feeling of numbness that may last as long as an hour. The sensory aura may also expand to involve the inside of the mouth, affecting the inside of one cheek and half the tongue. The slow spread of positive symptoms (the scintillations or the tingling) followed by negative symptoms (scotoma or numbness) is very suggestive of migraine aura and contrasts significantly with an ischemic event, such as a transient ischemic attack, wherein all symptoms begin concomitantly.

A language aura occurs much less commonly than the visual and sensory type auras. This consists of transient language problems that may range from mild word-finding difficulties to frank dysphasia with paraphasic errors.

The least common aura type, motor aura, involves unilateral weakness in the limbs and possibly the face. Most patients with motor aura also report sensory symptoms, and many also have other attacks, including visual, sensory, or language aura. When one considers diagnosing a motor aura, it is most important to distinguish true motor weakness from clumsiness based on proprioceptive loss caused by sensory aura. To date, research studies have linked motor aura to three separate genetic mutations. As a result, motor aura is classified separately from the other forms of migraine aura, and is referred to as hemiplegic migraine. Hemiplegic migraine can be further classified as either familial or sporadic. Familial hemiplegic migraine patients have at least one first- or second-degree relative with the same disorder. Sporadic hemiplegic migraine (SHM) is thought to be the result of a new mutation, and a patient with SHM may or may not carry one of the three gene variants already linked to the familial form.

OTHER MIGRAINE VARIANTS

Basilar-type migraine is a variant of migraine with aura wherein the symptoms mimic occlusive disease of the posterior cerebral circulation. These include reversible vertigo, ataxia, diplopia, dysarthria, and decreased consciousness. By definition, basilar migraine must have at least one aura symptom, and this must originate from the brainstem or both hemispheres simultaneously. If, for instance, the patient has paresthesias as part of a sensory aura, these would be expected to be bilateral.

Ophthalmoplegic migraine is thought to be rare and is most often seen in children or young adults. It involves a prolonged migraine-like headache (possibly lasting a week or more) accompanied or followed by paresis of the third, fourth, and/or sixth cranial nerve that may persist for days afterward. Originally considered a migraine variant, ophthalmoplegic migraine has been reclassified as a cranial neuralgia. In patients presenting with this variant, parasellar, orbital fissure, and posterior fossa lesions must be excluded with appropriate imaging, particularly magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA). In some cases, MRI has shown gadolinium enhancement of the affected cranial nerve, suggesting the condition may represent a recurrent demyelinating neuropathy.

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