A study published Wednesday in the journal Neurology found that people with traumatic brain injuries are more likely to have lower scores on cognitive tests by the age of about 70.
Scores were also more likely to decline rapidly after the first test if the participants had sustained multiple traumatic brain injuries, were unconscious due to the head injury, or were over 25 years old at the time of the injury.
“We now know that even a single traumatic brain injury can lead to subsequent deterioration in cognitive function,” he says. Marianne Chanty-Ketterleis the study’s lead author and an assistant professor of psychiatry and behavioral sciences at Duke University School of Medicine.
Benefits of twin studies
Studies of identical and fraternal twins allow researchers to compare participants to each other while controlling for some, if not all, of the underlying genetic factors and childhood conditions of the twins. can. Identical twins share 100 percent of their genes, while fraternal twins share about half.
The study, which primarily involved white and male twins who were World War II veterans, began in the 1990s and was conducted by Duke University. The twins were born between 1917 and 1927 and were included in the national registry, which began in the 1950s.
Researchers spoke to 8,662 people. 7,188 participants participated as twin pairs and 1,474 participants participated without twins. In this study, a quarter of the twins reported at least one traumatic brain injury.
The study included 589 pairs of identical twins. Within that group, at least one Traumatic brain injury and having a concussion at age 25 or older were associated with lower subsequent cognitive test scores.
“Those two children were in the same family and had the same environmental factors at the time. They were both in the military,” Chanti-Ketel said. “Everything has very similar exposure.”
Cognitive function declines faster with age
Researchers asked participants whether they had experienced a traumatic brain injury. If it happened more than once. Whether you lost consciousness due to a traumatic brain injury. And what was the cause of the injury?
The researchers administered cognitive tests to participants over the phone every three to four years over 12 years. About half of the participants completed all four tests, Chanti-Ketterl said.
To test memory and thinking skills, researchers asked questions such as “Who is the president of the United States?” “Can you subtract 7 from 100 until I tell you to stop?” And on the test, answers were scored from 0 to 50, he said Chanti-Ketterl.
Among all participants, those who had at least one traumatic brain injury, a head injury that resulted in loss of consciousness, or an injury that occurred at age 25 or older were more likely to have lower scores on cognitive tests. Ta.
Loss of consciousness, multiple traumatic brain injuries, and injuries occurring over age 25 were also associated with faster declines in cognitive test scores on subsequent tests.
The researchers controlled for medical conditions such as excessive alcohol consumption, smoking, cardiovascular disease or risk, and neurological conditions such as Parkinson’s disease and depression. Most of the associations between traumatic brain injury and cognitive decline “remained statistically significant.”
The study did not control for people’s physical activity or hearing loss, which have been found to be associated with cognitive decline later in life.
The study, written by researchers at Duke University and the University of California, San Francisco, is the first to repeatedly measure cognitive function associated with traumatic brain injury over more than 10 years of a person’s “later life.” be.
Funded by the National Institute on Aging and the Department of Defense.
One limitation of this study is that participants (or their proxies) self-reported whether they had a traumatic brain injury. Researchers said it’s possible someone forgot to report an injury.
Participants were also homogeneous: male, primarily white, World War II veterans born within the past 10 years in the United States. Researchers say the results may not be generalizable to women or people of other races, ethnicities, or backgrounds.
Chanti-Ketel said the researchers did not analyze the causes of injuries, such as during sports or military service, but details are included in the report.
Chanti-Ketel said more time was needed to analyze the data, which included reports that some participants had fallen while boating, for example.
The findings emphasize the importance of taking reasonable steps to avoid head injuries, such as wearing a helmet and using seat belts, Elser said. Editor The study was published at the same time as the study on Wednesday.
People with traumatic brain injuries shouldn’t feel like they’re “destined to have cognitive impairment or develop dementia as they get older,” she says.
“We know there are other risk factors for dementia, such as lack of exercise and poor diet, but we may be able to control them to some extent,” Elser says. “So if you’ve sustained a head injury, it makes perfect sense to talk to your doctor about other steps you can take to protect your brain as you age.”