People who have mild traumatic brain injuries may be more likely to have lasting functional deficits that get in the way of daily activities than patients who experience other types of injuries, a U.S. study published in JAMA Neurology and summarized by Reuters Health suggests.

The new study involved 1,154 patients with mild traumatic brain injuries and 299 patients with orthopedic injuries but no head trauma.

Two weeks after their injuries, 87 percent of brain injury patients and 93 percent of the other trauma patients reported functional limitations, a difference that was too small to rule out the possibility that it was due to chance. The groups remained on a similar trajectory until six months after their injuries.

After one year, however, brain injury patients fared worse. By this point, 53 percent of them still had functional limitations, compared with 38 percent of the other trauma patients.

“Unfortunately, many patients with mild traumatic brain injuries do not get any follow-up care after being discharged from the hospital,” said study leader Lindsay Nelson of the Medical College of Wisconsin in Milwaukee. While patients with moderate to severe brain injuries are almost always admitted to a hospital or intensive care unit, there’s less consensus about the best way to manage people with milder injuries.

Even when brain injuries are called “mild,” they can still lead to persistent physical, psychiatric and cognitive problems that result in lasting impairments and disability, especially when people go untreated.

Car crashes were the most common cause of brain injury in the study, accounting for 36 percent of cases, followed by falls at 24 percent.

The study wasn’t a controlled experiment designed to prove whether or how different types of traumatic injury might directly cause distinct functional deficits over time.

One limitation of the analysis is that researchers only included patients treated at level 1 trauma centers – hospitals that see the most serious cases, the study team notes. And, they only looked at patients who had head CT scans to confirm whether they had brain injuries.