Aug. 1 (UPI) -- Researchers believe they have found the first evidence that a single traumatic brain injury -- rather than repeated blows -- can be associated with an abnormal form of dementia.
A greater level of protein tau was found in patients with brain injuries compared to those without such trauma. The Mario Negri Institute for Pharmacological Research of Milan and the University of Glasgow in Scotland published the findings Wednesday in the journal Brain.
Tau's slow spread through the brain results in memory deficits and neuronal damage, including Alzheimer's disease. The authors believe that blocking tau propagation may have therapeutic effects.
Traumatic brain injury is a major cause of death and disability in the United States, with 153 people each day dying from injuries linked to it, according to the Centers for Disease Control and Prevention. And TBI contributed to 30 percent of all injury deaths.
"Even in milder cases, it represents a risk factor for dementia, such as chronic traumatic encephalopathy [CTE]," study leader Dr. Elisa Zanier of the Mario Negri Institute team said in a press release. "Understanding the mechanism linking an acute mechanical event to a progressive, degenerative brain disease would help the development of new therapies."
They analyzed brain specimens from 15 patients aged 19 to 89 who survived a year or more after a severe traumatic brain injury, and compared them with an equal number with no known history of TBI or neurological disease.
"In this material we saw evidence of much more widespread deposits of abnormal tau proteins in brain injured patients than in normal control brains," said Dr. Willie Stewart, an honorary clinical professor at the Institute of Neuroscience and Psychology at Glasgow.
They also observed the same type of abnormal tau in injured mice, which ultimately spread from the site of injury to remote brain regions. They said the amount of tau was reminiscent of prions spread, which are infectious proteins more commonly associated with brain diseases that include Creutzfeldt-Jakob.
Other researchers have linked TBI in children with an increased risk for attention-deficit/hyperactivity disorder up to seven years after the injury, according to a study released in March. They examined 187 children from 2003 to 2008 hospitalized overnight for traumatic brain injury or orthopedic injury at four hospitals in Ohio.