Nightly sleep duration, fragmentation, and quality and daily risk of migraine.

OBJECTIVE: To test the hypotheses that insufficient duration, high fragmentation, and poor sleep quality are temporally associated with migraine onset on the day immediately following the sleep period (day 0) and the following day (day 1). METHODS: In this prospective cohort study of 98 adults with episodic migraine, participants completed twice-daily electronic diaries on sleep, headaches, and other health habits, and wore wrist actigraphs for 6 weeks. We estimated the incidence of migraine following nights with short sleep duration, high fragmentation, or low quality compared to nights with adequate sleep with conditional logistic regression models stratified by participant and adjusted for caffeine intake, alcohol intake, physical activity, stress, and day of week. RESULTS: Participants were a mean age of 35.1 ± 12.1 years. We collected 4,406 days of data, with 870 headaches reported. Sleep duration ≤6.5 hours and poor sleep quality were not associated with migraine on day 0 or day 1. Diary-reported low efficiency was associated with 39% higher odds of headache on day 1 (odds ratio [OR] 1.39, 95% confidence interval [CI] 1.06-1.81). Actigraphic-assessed high fragmentation was associated with lower odds of migraine on day 0 (wake after sleep onset >53 minutes, OR 0.64, 95% CI 0.48-0.86; efficiency ≤88%, OR 0.74, 95% CI 0.56-0.99). CONCLUSION: Short sleep duration and low sleep quality were not temporally associated with migraine. Sleep fragmentation, defined by low sleep efficiency, was associated with higher odds of migraine on day 1. Further research is needed to understand the clinical and neurobiologic implications of sleep fragmentation and risk of migraine.

The migraine eye: distinct rod-driven retinal pathways' response to dim light challenges the visual cortex hyperexcitability theory.

Migraine-type photophobia, most commonly described as exacerbation of headache by light, affects nearly 90% of the patients. It is the most bothersome symptom accompanying an attack. Using subjective psychophysical assessments, we showed that migraine patients are more sensitive to all colors of light during ictal than during interictal phase and that control subjects do not experience pain when exposed to different colors of light. Based on these findings, we suggested that color preference is unique to migraineurs (as it was not found in control subjects) rather than migraine phase (as it was found in both phases). To identify the origin of this photophobia in migraineurs, we compared the electrical waveforms that were generated in the retina and visual cortex of 46 interictal migraineurs to those generated in 42 healthy controls using color-based electroretinography and visual-evoked potential paradigms. Unexpectedly, it was the amplitude of the retinal rod-driven b wave, which was consistently larger (by 14%-19% in the light-adapted and 18%-34% in the dark-adapted flash ERG) in the migraineurs than in the controls, rather than the retinal cone-driven a wave or the visual-evoked potentials that differs most strikingly between the 2 groups. Mechanistically, these findings suggest that the inherent hypersensitivity to light among migraine patients may originate in the retinal rods rather than retinal cones or the visual cortex. Clinically, the findings may explain why migraineurs complain that the light is too bright even when it is dim to the extent that nonmigraineurs feel as if they are in a cave.

Color-selective photophobia in ictal vs interictal migraineurs and in healthy controls.

Aversion to light is common among migraineurs undergoing acute attacks. Using psychophysical assessments in patients with episodic migraine, we reported that white, blue, amber, and red lights exacerbate migraine headache in a significantly larger percentage of patients and to a greater extent compared with green light. This study aimed at determining whether these findings are phase-dependent-namely, manifested exclusively during migraine (ictally) but not in its absence (interictally), or condition-dependent-ie, expressed uniquely in migraineurs but not in healthy controls. To determine whether the color preference of migraine-type photophobia is phase- or condition-dependent, we compared the effects of each color of light in each intensity between migraineurs during and in-between attacks and healthy controls. During the ictal and interictal phases, the proportion of migraineurs reporting changes in headache severity when exposed to the different colors of light increased in accordance with elevated light intensities. During the ictal phase, white, blue, amber, and red lights exacerbated headaches in ∼80% of the patients; however, during the interictal phase, light initiated headache in only 16% to 19%. Notably, green light exacerbated headaches in 40% and triggered headaches in 3% of the patients studied during the ictal and interictal phases, respectively. With one exception (highest red light intensity), no control subject reported headache in response to the light stimuli. These findings suggest that color preference is unique to migraineurs-as it was not found in control subjects-and that it is independent of whether or not the patients are in their ictal or interictal phase.