Vertigo as a symptom of migraine.

Migraine and vertigo are common disorders, affecting about 14% and 10%, respectively, of the general population. If migraine and vertigo were unrelated, the expected comorbidity would be 1%, whereas recent epidemiological studies indicate that 3.2% of the population have both migraine and vertigo. The excess comorbidity may be attributed to two factors: 1) vertigo syndromes (including Menière's disease, benign paroxysmal positional vertigo, and anxiety-related dizziness) that are more common in migraineurs than in controls and 2) vestibular migraine (VM) (vertigo as a symptom of migraine.) VM presents with attacks of spontaneous or positional vertigo lasting seconds to days. Headaches are often absent during acute attacks, but other migrainous features such as photophobia or auras, may be present. Like migraine headaches, VM triggers include stress, sleep deprivation, and hormonal changes. During acute attacks, there may be central spontaneous or positional nystagmus and, less commonly, unilateral vestibular hypofunction. In the symptom-free interval, vestibular testing shows mostly minor and nonspecific findings. The pathogenesis of VM is uncertain, but migraine mechanisms may interfere with the vestibular system at the labyrinth, brainstem, and cerebral cortex. Treatment includes vestibular suppressants for acute attacks and migraine prophylaxis for patients with frequent recurrences. However, treatment efficacy has not been validated by properly controlled clinical trials. VM does not fit into the 2004 International Headache Society Classification, in which "basilar-type migraine" must have at least two posterior circulation manifestations; isolated vertigo would not satisfy this criterion.