Headache after a traumatic brain injury is more common than previously understood, according to a recent study reported in the Journal of Neurotrauma.

In the first year after injury, 71% percent of study participants reported headache, much higher than earlier studies have found. The findings were particularly pronounced for women, with 74% reporting headache in that year compared to 63% of men.

For this study, researchers enrolled 452 patients who had been admitted to rehabilitation facilities after their brain injuries and followed them at regular intervals over the course of the year. The prevalence of headache remained high throughout the year, with 41% of participants reporting headache at three, six and 12 months after injury. A history of headache was also significant to the findings. Forty-five percent of patients who had headaches prior to their injury reported post-trauma headaches, compared to 19% with no history of headache.

Additionally, throughout the year, a high percentage of people, 22 to 29%, reported frequent headaches—multiple times per week or daily—compared to 4 to 5% of the general population.

Study authors note that according to diagnostic criteria, to be considered a post-traumatic headache, headache must occur within one week of a person regaining consciousness after injury. The study found, however, that 28% of participants reported new headaches long after that time period, including at six and 12 months after injury. The authors also noted that a previous study of military personnel found that only 27% of headaches developed within one week after the trauma.

The diagnostic limitations may lead to the underestimation of post-traumatic headache, the authors state, potentially affecting treatment and hindering injured people’s ability to pursue legal pathways to obtain money for more treatment.

The study was conducted by Jeanne M. Hoffman, Ph.D., of the University of Washington, and colleagues, and recently appeared online ahead of print publication.

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