CTE is caused when brain trauma triggers degeneration of brain tissue and a build-up of protein. This brain disease often comes from head injuries associated with contact sports.

According to the data, 80 percent of men in the test group, all of whom played sports, exhibited symptoms of chronic traumatic encephalopathy (CTE), a degenerative brain disease which can cause depression, dementia, and memory loss. (AP Photo/Elise Amendola)

There is a strong link between degenerative brain disease and serious head trauma, suggests a study published in the journal Brain. According to the data, 80 percent of men in the test group, all of whom played sports, exhibited symptoms of chronic traumatic encephalopathy (CTE), a degenerative brain disease which can cause depression, dementia, and memory loss.

The BU Center for the Study of Traumatic Encephalopathy notes CTE is caused when brain trauma triggers degeneration of brain tissue and a build-up of the protein called tau. Changes can be found months, years, or even decades after the injury occurred.

“It’s a gambler’s game to try to predict what percentage of the population has this,” Chris Nowinski, a co-author of the study and a co-director of the Center for the Study of Traumatic Encephalopathy at Boston University School of Medicine, told the New York Times. “Many of the families donated the brains of their loved ones because they were symptomatic. Still, this is probably more widespread than we think.”

For the research, experts from Boston University Center for the Study of Traumatic Encephalopathy and the Veterans Affairs Boston Healthcare System, in collaboration with the Sports Legacy Institute, reviewed the medical data from 85 people. Sixty-eight of those individuals had a history of playing sports. All of the subjects were between the ages of 17 and 98.

While the study did link head trauma and eventual brain disease, it did not indicate which players in contact sports were most likely to develop CTE. (Courtesy of Facebook)

The results of the 4-year study revealed 50 football players, 7 professional boxers, 4 National Hockey League players, and 21 veterans with a history of severe head trauma had symptoms of CTE. Many of the football players were linemen and running backs, high-contact positions on the team. Among the test subjects were a number of well-known athletes, including Dave Duerson, Cookie Gilchrist and John Mackey.

Researchers found the level of CTE varied among the test participants. Individuals with Stage 1 CTE reported loss of concentration, headaches and loss of attention. Stage 2 CTE sufferers reported short-term memory loss, explosive behavior and depression. Stage 3 CTE participants experienced trouble with basic functions and cognitive impairment. The final stage of CTE, Stage 4, found patients with symptoms of dementia, trouble speaking, and performing acts of aggression.

While the study did link head trauma and eventual brain disease, it did not indicate which players in contact sports were most likely to develop CTE. According to the researchers, it is severity and frequency of head trauma which must be taken into account when assessing risk.

“All concussions are not created equal,” said to the New York Times, Robert Cantu, a co-author of the study and a co-director of the encephalopathy center. “Parents have become paranoid about concussions and connecting the dots with CTE, and that’s wrong. The dots are really about total head trauma.”