Background and ObjectiveLimited data are available describing the frequency, severity, and consistency of prodromal symptoms followed by headache. This analysis of the PRODROME trial screening period characterized prodromal symptoms in people with migraine, including the most common symptoms and their severity, and the frequency and consistency with which prodromal symptoms were followed by headache.MethodsPRODROME was a multicenter, randomized, double-blind, placebo-controlled, crossover trial conducted in the United States that enrolled adults with 2-8 migraine attacks per month who stated they could identify prodromal symptoms that were reliably followed by a headache. The trial included a 60-day screening period designed to test the predictive validity of "qualifying prodrome events" before the onset of headache. Participants used an eDiary to report qualifying prodrome events, defined as prodromal symptoms whereby the participant was confident a headache would follow within 1-6 hours. This analysis evaluated common prodromal symptoms and their severity, time from prodrome onset to headache onset, and the percentage of participants who identified prodromal symptoms that were followed by a headache ≥75% of the time over the 60-day screening period.ResultsA total of 920 participants entered eDiary data, with a mean of 5.2 qualifying prodrome events during the 60-day screening period. A total of 4,802 qualifying prodrome events were recorded. The most common prodromal symptoms identified were sensitivity to light (57.2%; 2,748/4,802), fatigue (50.1%; 2,408/4,802), neck pain (41.9%; 2,013/4,802), sensitivity to sound (33.9%; 1,630/4,802), either difficulty thinking or concentrating (30.0%; 1,442/4,802), and dizziness (27.8%; 1,333/4,802). Of all qualifying prodrome events reported, 81.5% (3,913/4,802) were followed by headache of any intensity within 1-6 hours. For each participant, a mean of 84.4% of their qualifying prodrome events were followed by a headache within 1-6 hours, with 76.9% of participants identifying qualifying prodrome events that were followed by headache within 1-6 hours ≥75% of the time.DiscussionParticipants were able to identify migraine attacks in which prodromal symptoms were reliably followed by a headache within 1-6 hours. These findings suggest the potential for initiating treatment during the prodrome to prevent headache.Trial Registration InformationClinicalTrials.gov NCT04492020. Submitted: July 27, 2020; First patient enrolled: August 21, 2020. clinicaltrials.gov/study/NCT04492020.