For traumatic brain injury (TBI) and certain brain diseases, it appears that risk may extend in both directions, according to a study published June 17, 2026. Neurology®Medical Journal of the American Academy of Neurology.
Studies have shown that suffering a traumatic brain injury may increase your risk of developing stroke, dementia, epilepsy, or Parkinson’s disease. In this new study, researchers looked at older veterans who had recently suffered a traumatic brain injury to see if they were more likely to develop any of these symptoms compared to people without a recent traumatic brain injury.
They found that older veterans who had recently suffered a traumatic brain injury were three to four times more likely to have been diagnosed with one of four conditions in the previous year than veterans of the same age without a traumatic brain injury.
This study does not prove that the condition causes an increased risk of traumatic brain injury. Just show the relevance.
These findings suggest that the period after diagnosis of a neurological disease is a critical period for the prevention of traumatic brain injury. Our findings raise the possibility that dementia, stroke, epilepsy, and Parkinson’s disease themselves are risk factors for traumatic brain injury in older adults. Neurological disorders often impair motor control, balance, gait, coordination, and thinking skills, all of which increase susceptibility to falls, which are the leading cause of traumatic brain injury in older adults. ”
Dr. Carrie Peltz, study author, San Francisco Veterans Affairs Health System, California
In the study, researchers looked at 13,801 veterans with an average age of 78 who had recently suffered a traumatic brain injury and compared them with 41,403 veterans of the same age who did not have a traumatic brain injury. They looked at health records for a year before and after a traumatic brain injury, or a similar period of time for people without a traumatic brain injury. People who had any of the four conditions before that point were not included in the study.
For all four conditions, people with TBI were more likely to develop the condition in the previous year than people without TBI. For stroke, the rate was 64 per 1,000 person-years for people with traumatic brain injury, compared with 20 for people without traumatic brain injury. Person-years represent both the number of people who participated in the study and the time each person spent in the study. For dementia, the rate for those with TBI was 58 compared to 19 for those with TBI. For epilepsy, the TBI rate was 4 compared to 14 for TBI. And for Parkinson’s disease, the ratio was 10 and 3.
When the researchers adjusted for other factors that can affect the risk of TBI, such as diabetes, smoking, and history of a heart attack, they found that people with TBI were four times more likely to be recently diagnosed with epilepsy and three times more likely to be diagnosed with stroke, dementia, or Parkinson’s disease.
This study also looked at another direction in which participants develop some symptoms after TBI compared to before TBI. Researchers have found that after a traumatic brain injury, people are twice as likely to develop a stroke or epilepsy as before the traumatic brain injury. They were 24% more likely to develop dementia. However, the prevalence of Parkinson’s disease did not differ between the two groups.
Professor Peltz said the failure to find an increased risk of Parkinson’s disease could be due to the study’s short follow-up period, as previous studies have found an increased risk of Parkinson’s disease.
“Our results argue for screening older adults for fall risk at diagnosis and prompting them to physical therapy, occupational therapy, and fall prevention programs,” Peltz said. “Strength and balance training, home modifications such as adding handrails or removing trip hazards, and reviewing medications have all been shown to reduce the risk of falls among older adults in general.”
A limitation of this study is that the request for medical information 1 year after TBI excludes people with severe TBI who die within 1 year. In contrast, people with mild TBI who did not seek medical care were also not included. Additionally, all participants were military veterans, so the results may not apply to other populations.
This research was supported by the U.S. Department of Defense.
sauce:
American Academy of Neurology
Reference magazines:
Peltz, C. Others. (2026). Neurological diagnosis before and after traumatic brain injury. Neurology. DOI: 10.1212/wnl.0000000000218214. https://www.neurology.org/doi/10.1212/WNL.0000000000218214
