Appraisal of Headache Trigger Patterns Using Calendars.

Using experimental, yet realistic, headache calendars, this laboratory study evaluated the ability of individuals to identify the degree of association between triggers and headaches.Individuals with headache often record daily diaries or calendars to identify their patterns of triggers.This cross-sectional, observational study included adults with migraine, tension-type, or cluster headache who had ever experienced more than 5 attacks. Participants (N = 300) were presented with headache calendars and asked to rate the strength of the relationship (how strongly one causes the other) between 3 experimental triggers (high stress, poor sleep, and cinnamon) and headache using a 0 ("no relationship") to 10 ("perfect relationship") scale for each calendar.Calendars with a high positive correlation between trigger and headache had higher participant ratings than those with low correlations. The median [25th, 75th] of ratings for each correlation level was low correlation: 1 [0, 4], medium: 4 [2, 5], and high: 5 [4, 8], P < .0001. However, participants appeared to ignore negative associations (ie, trigger present with no headache) and rated calendars with more headache days as having higher associations, regardless of the true relationship. The ratings for 2, 6, and 26 headache days were 1 [0, 3], 4 [1, 6], and 8 [0, 10], respectively (P < .0001). Participants' previous beliefs about the triggers also affected their ratings (average correlation across triggers: r = 0.25, P < .0001).This laboratory task supports the notion that individuals with headache are able to identify the association between headaches and triggers using headache calendars. However, these judgments can be biased by the individuals' previous beliefs about the trigger and by the degree of headache activity.