Effects of Pre-Accident History of Migraine on Acute Concussion Symptoms and Recovery: The Toronto Concussion Study
Laura Langer1, Mark Bayley 1,2, David Lawrence 1,2, Paul Comper1, Tharshini Chandra 1, Evan Foster 1, Jonathan Gladstone1,3
1University Health Network - Toronto Rehab Institute, 2University of Toronto, 3The Hospital for Sick Children
Objective:
To characterize concussion symptoms and recovery trajectory in adults in the general population with a concussion and a history of migraine.  
Background:
History of migraine has been identified as a potential risk factor for persisting post-concussion symptoms (PCS) in studies in selected populations; however, the literature on migraine as a PCS risk factor in the general adult population is limited.
Design/Methods:

A prospective cohort analysis of adults diagnosed with concussion in referring Emergency Departments and assessed at a concussion clinic within one-week post-injury.  Accidents were not claim-related (i.e. not workplace or motor vehicle collision related). SCAT 3, headache questionnaires, and biweekly physician assessments were administered Weeks 1 – 8 and weeks 12 and 16 post-injury.

Results:
302 adults (59% female), mean age of 33.6 years (13.0 SD), were in this analysis; 116 (38%) had a pre-accident history of migraine, 49% of females and 23% of males, and 84% had active migraine pre-injury. Individuals with pre-accident migraine history had significantly higher (p=0.007) SCAT 3 scores than those without migraine in the acute phase (is the p=0.007) and through week 16 (p=0.002). Pre-accident migraine history did not increase likelihood of post-traumatic headache (PTH) in the acute phase; however, it was related to a 2.79 times risk (95%CI 1.37 – 5.68, p=0.005) at Week 12 and 2.57 times risk (95%CI 1.13 – 5.83, p=0.025) at Week 16 of experiencing headaches above pre-accident baseline headache frequency. Individuals with a pre-accident history of migraine were also 4.32 (95%CI 1.75 – 10.68, p=0.0015) times more likely to not be deemed “recovered” by physician at Week 8. 
Conclusions:

Adults with pre-accident history of migraine have more acute, severe, and prolonged concussion symptoms. A pre-accident history of migraine predicts risk for continuing PTH above pre-accident headache frequency at 12 and 16 weeks post-concussion and delayed overall recovery at 8 weeks post-injury.