Mechanisms of increased sensitivity to noise and light in migraine headache.

To determine whether phonophobia is a manifestation of loudness recruitment, the hearing and auditory discomfort thresholds to an 8000 Hz tone were measured during the headache-free interval and again during an attack of migraine in 16 migraine sufferers. The visual discomfort threshold was also determined. For comparison, measures were taken in 16 non-headache controls of similar age and sex distribution. Auditory and visual discomfort thresholds decreased substantially during attacks of migraine. Increases (three subjects) or decreases (three subjects) in hearing threshold during attacks of migraine were significantly greater than the variation recorded in control subjects from Session 1 to Session 2. The findings do not support the view that phonophobia in migraine is a manifestation of loudness recruitment, although cochlear disturbances might mediate hearing loss in some cases. Disruption of central sensory processing mechanisms during migraine could increase sensitivity to quiet sounds, and contribute to phono- and photophobia.