More than half of patients presenting to an emergency department with mild traumatic brain injury (TBI) are still reporting problems a year later, a US study shows.

Those who had acute abnormalities on brain CT in emergency were 24% more likely to report functional impairment at 12 months that affected their daily life than those whose brain scans were normal, the researchers reported in JAMA Neurology.

The findings highlighted the need to provide better follow-up and ongoing care for people with mild TBI, the authors said.

The study followed 1154 people (mean age 41, 66% male) who attended 11 of the best-equipped trauma centres across the US and were classified as having mild TBI, as measured by a score of 13-15 on the Glasgow Coma Scale.