Dizziness and migraine: a causal relationship?

Both migraine and dizziness are very frequent complaints, but the comorbidity of the two disorders is higher than it might be expected to be on the basis of chance alone. This implies a possible causal relationship, but definite diagnostic criteria for migraine-related vertigo are still lacking. Very recent attempts in this direction have shown that migraine may be the third leading cause of vertigo and that migraine-related vertigo may be effectively treated. A review of the literature on this topic, which includes some preliminary data of our own, demonstrates the difficulty in pinpointing migraine-associated vertigo as a clearly-defined entity. However, there is a measure of agreement on a few points: the spells of vertigo occur in patients who habitually suffer from motion sickness, and who have a history of migraine, either without or with aura; the delay between migraine and vertigo onset may be several years; migraine-related vertigo may be described as rotatory and/or as a feeling of unsteadiness, and single spells can occur without any other accompanying symptoms, however, when spells do occur in association with headache, they usually precede it. The vertigo duration may be shorter or longer than that of the migraine aura since it ranges from a few seconds to a continuous condition of unsteadiness.