A bump to the head from slipping on the stairs, falling off to skateboard, or running into an open cupboard door has long been seen as a temporary injury, something resolved with a little rest. But a growing body of research suggests that, for some people, even concussions that seem to have serious, long-lasting consequences, including an increased risk of Parkinson's disease and dementia.

Uncovering Long-term Risk

The studies looked at military veterans with different levels of traumatic brain injury, including the types of concussions that are held every day in civilian life, said Kristine Yaffe, MD, professor of psychiatry, neurology and epidemiology, whose lab conducted the studies. Earlier studies in civilian populations identified similar long-term effects from concussions.civilian life, said Kristine Yaffe.

Searching for the Missing Link

Now that scientists know there is a connection between concussion and increased risk for neurological decline – the challenge is untangling what occurs in between.neurological decline – the challenge is untangling what occurs in between.

Researchers suggest several possible mechanisms that could link concussion and mental decline. Perhaps the concussion triggers a cascade that increases abnormal protein buildup in the brain, a common hallmark of neurodegenerative diseases. The concussion might cause inflammation or vascular changes. Another theory is that the injury could make the brain more vulnerable overall, what the researchers call a loss of brain reserve.

A Better Way to Diagnose

The two are focused on using long noncoding RNAs (lncRNAs) – molecules that are remarkably tissue-specific and can leak out of a cell when it is injured. Distinctive lncRNAs found in the blood can be traced to broken bones, torn muscle, or injury to organs like the heart and kidney. Likewise, brain-specific lncRNAs in the blood would indicate a brain injury.

"The brain is making a whole panel of lncRNAs that occur nowhere else in the body," said Lim. "We realized that exquisite brain-specificity makes lncRNAs attractive as biomarkers for concussion."concussion."

Currently, head injuries that show up on a CT scan can be diagnosed by protein biomarkers such as GFAP and UCH-L1, but those may not be sensitive enough to pick up concussions, according to Lim. He hopes lncRNAs will offer a more sensitive biomarker for concussion, one that may be even specific enough to locate the injury to particular regions of the brain.concussion, one that may be even specific enough to locate the injury to particular regions of the brain.

Major Gap in Care

Researchers say it's important to avoid a second concussion before the first one, because repeated concussions multiply the damage. Cognitive rehabilitation exercises, like specially designed video games, may also help boost brain reserve.heals, because repeated concussions multiply the damage. Cognitive rehabilitation exercises, like specially designed video games, may also help boost brain reserve.

TRACK-TBI

Follow-up care to treat symptoms such as headaches, dizziness, depression and anxiety can help prevent lasting disability, according to Manley, professor of neurosurgery. Manley is the principal investigator of the multicenter TRACK-TBI (Transforming Research Clinical Knowledge in Traumatic Brain Injury) study, the largest precision medicine study of TBI to date, which is tracking thousands of people nationwide who visit the emergency room for head trauma.and anxiety can help prevent lasting disability, according to Manley, professor of neurosurgery.

Manley is the principal investigator of the multicenter TRACK-TBI (Transforming Research Clinical Knowledge in Traumatic Brain Injury) study, the largest precision medicine study of TBI to date, which is tracking thousands of people nationwide who visit the emergency room for head trauma.

TRACK-TBI has found that less than half of patients who visit the emergency room for concussion received any follow-up within three months, including educational materials and doctor's visits.patients who visit the emergency room for concussion received any follow-up within three months, including educational materials and doctor's visits.

"Many of those who are not needing medical attention," he said. "It's a major gap in care that represents an important public health issue in this country." In the coming years, TRACK-TBI will attempt to answer some crucial questions, such as the value of blood-based biomarkers and advanced MRI imaging techniques in diagnosis and the role of genetics. It will also test new phase II drugs in clinical trials.