For the study, patients with either a mild or moderate brain injury were compared to people with no history of brain trauma.
Scans taken six days after an injury showed damage in the brain white matter, which can disrupt its ability to transmit signals.
Trauma patients also scored 25% lower on a memory and thinking skills than people with no brain injury.
In other health news, the number of strokes have gone down in people over age 65 by 40% over the past two decades.
The reason for the decrease is unclear, but researchers from the University of California San Francisco School of Medicine found stroke risk factors, like smoking and cholesterol also decreased.
Stroke remains the fourth leading cause of death in the U.S.
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