MIGRAINE AURA EXPLAINS A RARE—AND STARTLING—VISUAL PHENOMENON

SEATTLE—A rare visual abnormality—acute complete upside-down reversal of vision—joins the list of visual disturbances that can herald a migraine attack. At the 124th Annual Meeting of the American Neurological Association, researchers described the rare phenomenon in two case reports.

Two teenagers (ages 18 and 19) experienced intermittent episodes of reversal of vision over a period exceeding one year. The transient visual illusion was described as a 180-degree rotation of visual image in the coronal plane. The episodes were followed by moderate or severe throbbing migraine headaches. One patient also reported occasional micropsia during the same attack. "Reversal of vision episodes were brief, lasting less than five minutes, but their first and abrupt appearance was frightening for both of the patients," reported Puiu Nisipeanu, MD, PhD, of the Hillel Yaffe Medical Center, Hadera, Israel.

Neurologic examination, magnetic resonance imaging of the brain, and auditory evoked potentials were normal in both of the patients. The normal findings were surprising, since reversal of vision is "almost always associated with brain pathology," noted Dr. Nisipeanu and colleagues. Reversal of vision has previously been reported in patients with head trauma, epilepsy, tumors, brainstem-cerebellum ischemia, or parieto-occipital ischemia.

Upside-down reversal of vision is "an extremely rare or unreported expression of migraine aura," noted the researchers. A literature search turned up only one autobiographic account of reversal of vision associated with headache. Published in Trans Ophthalmology (UK) in 1949, the article suggested that the visual phenomenon was a manifestation of migraine.

Visual disturbances are the most frequent features of migraine aura. Most common are scotomas that are experienced as glittering lights, zigzags across the visual field, or shimmering wavy lights. A variety of other visual disturbances have been reported by migraine patients, including metamorphopsia, micropsia, macropsia, teichopsia, distorted contours, changes in color, diplopia, polyopia, and movement of stationary objects.

Current hypotheses about neurologic changes underlying migraine aura involve cortical spreading depression, and the visual cortex has the lowest threshold for cortical spreading depression, the researchers pointed out. "Dysfunction in these cortical areas during the migraine aura may interfere with the mechanisms responsible for the accurate computation of the topographical map of the retinal image," suggested Dr. Nisipeanu.

-Alice Goodman
Contributing Writer

Suggested Reading
River Y, Ben Hur T, Steiner I. Reversal of vision metamorphopsia: clinical and anatomical characteristics. Arch Neurol. 1998;55:1362-1368.