Clinical Edge

Summaries of Must-Read Clinical Literature, Guidelines, and FDA Actions

Headache Triggers and Daily Headache Activity

Surprising values of headache triggers were found to have consistent associations with headache activity across a variety of triggers in a new study. A secondary prospective cohort analysis of the Headache Prediction study followed 95 individuals with episodic migraine who contributed 4,195 days of diary data. Information was collected on daily levels of several common headache triggers: number of caffeinated beverages, number of alcoholic beverages, stress, and mood disturbance. Researchers found:

  • Participants experienced a headache attack on 1,613 of 4,195 days (38.5%).
  • Each of the triggers was modestly related to the probability of experiencing a future headache in a complex manner.
  • However, when expressed as a “surprisal”, the associations were simplified and strengthened.
  • Each of the individual trigger surprisals exhibited a meaningful association with the development of a future headache attack.


Turner DP, Lebowitz AD, Chtay I, Houle TT. Headache triggers as surprise. [Published online ahead of print March 28, 2019]. Headache. doi:10.1111/head.13507.


This remarkable study, reported by psychology statisticians at Harvard, used data from a prospective cohort study conducted from 2009-2014 in North Carolina. They noted scant extant information about headache triggers. Their novel idea was that a surprising event might be key to a headache trigger. Subjects recorded a twice daily diary of alcoholic and caffeinated beverages and validated tools, the Daily Stress Inventory and Profile of Mood States-Short Form. Using complex information theory, the statisticians created a formula for “surprisal.” Surprisals from each of the 4 headache triggers were then summed to create a trigger surprise score used to estimate daily headache risk for that day. This surprisal score exhibited superior performance compared to any individual trigger alone (P < .0001), and although total prediction results were modest, the investigators pointed a way forward to future exploration of trigger factors, surprisal, and whether this model can be used clinically in precisely defined headache disorders (e.g. migraine, cluster, etc.) —Stewart J. Tepper, MD, FAHS, Professor of Neurology, Geisel School of Medicine at Dartmouth, Director, Dartmouth Headache Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH.