Underlying Vestibular Dysfunction May Be Cause of Migraine-Related Dizziness

Newswise — An estimated 25 million people in the United States experience migraine headaches. Nearly a third of these individuals also suffer related episodes of vertigo or dizziness, accounting for nearly three percent of people in the US with dizziness associated with migraine headaches.

Migraine headaches may be characterized by a pulsating one sided headache that interferes with daily life, high sensitivity to lights and sound, irritability, nausea, or extreme anxiety. Some migraine sufferers also experience an aura (flashing lights, bright spots, blurry vision, blind spots, or even auditory, sensory, or motor problems) about an hour before headache onset. A migraine episode can also include debilitating vertigo, or dizziness, known as migraine-related dizziness.

Researchers do not know the cause and process (pathophysiology) behind migraine-related dizziness, but many believe a relationship with vestibular function, i.e., the sense of balance in the inner ear, is involved. Determining the cause and process of a disorder is an essential element in the development of effective treatments. In the pilot study, "Pathophysiology of Migraine-Related Dizziness," investigators, Joseph Furman, Dawn Marcus, Patrick Sparto, Mark Redfern, and J. Richard Jennings, all of the University of Pittsburgh, address the cause and process of migraine-related dizziness by exploring the suspected relationship with vestibular abnormalities. The results of their work will be presented in a poster at the Mid Winter Meeting of the Association for Research in Otolaryngology (http://www.aro.org) being held February 22-26, 2004 at the Adam's Mark Hotel, Daytona Beach, FL.

Methodology: Three groups composed of five subjects were included in the study: (1) headache-free controls (C), (2) those who met the International Headache Society (IHS) criteria for migraine but who had no symptoms suggestive of a vestibular system abnormality (M-V), and (3) those who met both IHS criteria for migraine and the Neuhauser criteria for migraine-related vestibulopathy (M+V) (referred to in the study as migraine-related dizziness (MRD)). Subjects with recognized neurotologic syndromes such as Meniere's disease were excluded from all groups.

Each subject was tested with: Earth-vertical axis rotation (EVAR), off-vertical axis rotation (OVAR), visual-vestibular interaction, computerized dynamic platform posturography (CDP), optic flow in a virtual environment, subjective visual vertical (SVV) using rod and disk, and reaction time (RT) during rotation.

Results: Abnormalities in subjects with migraine-related dizziness included: decreased magnitude of the vestibulo-ocular reflex (VOR), increased sway on Equitestâ„¢ platform posturography, increased sway in response to optic flow in an immersive virtual environment, slowed reaction time during a dual-task paradigm assessing interference between attentional processes and the VOR, and excessive visual dependence of subjective visual vertical.

Conclusion: The results of this pilot study suggest that patients with migraine-related dizziness have abnormalities in vestibular function between episodes of migraine headache or dizziness and are more visually dependent than persons with migraine without vertigo or headache-free controls. The authors speculate that the basis for these findings may relate to mechanisms controlling serotonin, a neurotransmitter, in the central vestibular system.