Nordhaug LH, et al. - Authors performed a population-based cohort study to investigate if subjects hospitalized due to a head injury more often developed a new headache or experienced exacerbation of previously reported headache compared to the surrounding population. In this study, they identified a higher tendency for new onset and worsening of pre-existing headache and persistent headache among individuals hospitalized due to a head injury. The entity of the ICHD-3 beta (the International Classification of Headache Disorders, beta version of third edition) diagnosis “persistent headache attributed to traumatic injury to the head” was thus supported by the study.