Anyone with migraine is well aware that one’s perception of sensory information is out of whack during an attack. Photophobia (sensitivity to light) and phonophobia (sensitivity to sound) are the two most commonly addressed sensory changes, but they're not the only sense that can be affected. Allodynia, which is sensitivity to touch, can make it feel like your hair hurts or your clothes are too tight or can make the lightest touch seem painful or irritating. Osmophobia makes odors smell too strong, unpleasant, or just “off.” It turns out that these characteristics of migraine attacks aren’t limited to attacks—even between attacks, people with migraine are more sensitive to sensory input than those without migraine.

An article in the November issue of the journal Current Pain and Headache Reports reviews evidence from a variety of studies that investigate the differences between sensory processing in people with migraine and without. It pays close attention to the differences that occur between migraine attacks (the interictal period), which is what I focus on here. It’s a fascinating subject because it illuminates potential differences in the brains of people with migraine not just during an attack, but all the time.

Sound: About two-thirds of people with migraine report sensitivity to sound between migraine attacks. In a study on the topic, only 6% of people with migraine could withstand high intensity sound stimulation without irritation, while 44% of people without migraine were not irritated. That intensity caused pain in 69% of people with migraine and in only 25% of people without migraine. The threshold for discomfort was also lower in people with migraine.

Smell: Measured between migraine attacks, people with migraine were able to detect vanillin and acetone at lower concentrations than those without migraine. These two odors are significant because vanillin is a pure olfactory nerve stimulant and acetone stimulates both olfactory and trigeminal nerve endings (and the trigeminal nerve plays an important role in migraine). Also, about 50% of people with migraine report that odors can trigger their migraine attacks.

Sight: Light aggravates the pain of a migraine attack for 60-90% of migraineurs (different studies have found different percentages). Between attacks, 75% report sensitivity to light. People with migraine also have lower thresholds for visual discomfort than those without migraine.

Touch: During migraine attacks, about 60-70% of people find touch-related sensations that are normally innocuous to be painful—cutaneous allodynia is the technical term for this. Even everyday things like shaving, showering, wearing jewelry, and brushing hair can be painful. People with cutaneous allodynia may also be more sensitive to light and sound than those without cutaneous allodynia.

Harriott, A. M., & Schwedt, T. J. (2014). Migraine is Associated With Altered Processing of Sensory Stimuli. Current pain and headache reports, 18(11), 1-7.