A 25-year-old former college football player showed signs of a type of brain degeneration from repeated trauma, say researchers who described the autopsy-confirmed case.

Chronic traumatic encephalopathy (CTE) is a neurodegenerative disorder associated with repetitive head impacts. Symptoms may include memory loss, impaired judgment, depression and progressive dementia. CTE can only be diagnosed after death by examining the brain.

Monday's issue of JAMA Neurology includes a letter describing CTE in a 25-year-old man born with a heart valve disorder. He died of cardiac arrest secondary to a heart infection after playing football for 16 years and experiencing an estimated more than 10 concussions while playing.

Dr. Ann McKee and Dr. Jesse Mez of Boston University School of Medicine ran neuropsychological tests on the man when he showed symptoms a year before his death, and then conducted an autopsy, reviewed his medical records and interviewed family members.

"Focal lesions of CTE have been found in athletes as young as 17 years; however, widespread CTE pathology, as found in this case, is unusual in such a young football player," they wrote.

To their knowledge, it's the first such case to include neuropsychological testing to document the type of cognitive issues with CTE.

In this case, the athlete started playing football when he was six, including three years of college football as a defensive linebacker.

His first concussion occurred at age eight. During his freshman year of university, he experienced a concussion with momentary loss of consciousness followed by headaches, neck pain and other symptoms such as difficulty with memory and concentration.

At the start of his junior season, he stopped playing football because of ongoing symptoms. He began failing courses despite having above-average grades previously.

The player, who had a family history of addiction and depression, later had difficulty maintaining a job and began using marijuana to alleviate headaches and anxiety and to help him sleep. At age 23, he became verbally and physically abusive to his wife, a change from his prior demeanour, the researchers said.

Experts unanimously supported postconcussive syndrome as the primary diagnosis with possible CTE and major depression contributing.

Future studies examining players during their life with neuropsychological tests, imaging and other tests will be essential to improve the diagnosis of CTE during life, the researchers said.

Pull from the game

It is difficult to go back and report on the number of concussions, but unfortunately it's often the only information available, said Dr. Charles Tator, director of the Canadian Concussion Centre at the Krembil Neuroscience Centre at Toronto Western Hospital. He was not involved in the study.

"This is another example of a youngster perhaps not being pulled from the game soon enough," Tator said. "They documented about 10 concussions so for this kid, way too many. Maybe he should have been advised to play golf after his second concussion."

For Tator, concussion and its consequences are a public health concern given how common they are in Canada.

"We are hard playing people. We are adventurous people. We take a lot of risks not just in sports, but when we walk across the street listening to our music, we don't look both ways. When we ski, we ski into the trees and crash."

Tator doesn't want to scare parents and children from playing sports but he wants them to be aware of the risks of collision sports.

The case, its findings and uncertainties highlight a number of important developments in the field of concussion and CTE, according to a journal editorial published with the letter.

These include:

How often do concussions occur in sports?

Who takes longer to recover and why?

What are the long-term risks of playing contact sports with high rates of concussion?

Why did CTE occur in this particular athlete?

"What stands out from this case is that 10 years after the first publication of CTE in football, and nearly 50 years of pathologic findings in boxing, a case report remains highly informative in framing important unmet needs in the field of concussion," said Dr. James Noble of the neurology department at Columbia University in New York.

The study was funded by the U.S. National Institute of Neurological Disorders and Stroke, Department of Defence, Department of Veterans Affairs, the Veterans Affairs Biorepository, the National Institute of Aging, Boston University Alzheimer's Disease Center, the National Operating Committee on Standards for Athletic Equipment, the Sports Legacy Institute, the Andlinger Foundation, WWE and the National Football League.