Tech & Science

Chronic Traumatic Encephalopathy Without Concussion History Found In Athletes, Raising New Concerns

Aaron Hernandez is one of the most famous individuals to have developed CTE from a history of contact sports. Patrick McDermott/Getty Images

Chronic traumatic encephalopathy is a degenerative brain disease believed to be linked to concussions, a brain injury caused by a forcible blow to the head. But new research suggests that one does not necessarily need to obtain a concussion to develop the condition. Any head injury repeated enough times may be enough.

The study, published Thursday in Brain, concluded that hits to the head that do not cause concussions or even side effects such as headaches, dizziness, visions problems, or confusion, can still cause chronic traumatic encephalopathy, or CTE, if repeated enough over an extended period of time, NPR reported.

Related: Concussion In Football: Pop Warner CTE Lawsuit Could Change Youth Sports

The study took nearly seven years to complete and involved researchers from six different institutions in three different countries. Using adult mice specifically bred for the study, the team conducted experiments intended to reenact head injuries humans may receive in certain situations. The team also used post-mortem brain and spinal cords of eight teenage and young adults. Four of the humans males had sustained sports-related closed head impact injuries one to four months before their death and the other four had no such injuries.

Related: Aaron Hernandez CTE Diagnosis Asks NFL Another Horrible Concussion Question

Results revealed biological evidence of CTE in the brains of the young adults. They had abnormal accumulation of tau protein, a brain protein that appears to collect in large amounts in patients with certain conditions such as CTE and Alzheimer’s disease.

These abnormally high protein build-ups surprised the researchers because the test subjects had not sustained concussion but rather only minor head injuries prior to their death. According to the study, these results show both animal and human evidence of CTE occurring without a concussion.

"We've had an inkling that subconcussive hits—the ones that don't [show] neurological signs and symptoms—may be associated with CTE," Dr. Lee Goldstein, an associate professor of psychiatry at the Boston University School of Medicine and the lead investigator on the study said, NPR reported. "We now have solid scientific evidence to say that is so."

CTE is a progressive degenerative brain disease that develops in an estimated 17 percent of people with a history of head and brain trauma. Some of the most common symptoms of this condition include memory loss, confusion, impaired judgment, depression and suicidal thoughts. While CTE is linked to a history of repeated concussions, up to 20 percent of cases have no history of concussion, NPR reported. 

This study may yield useful clues about what causes CTE and what can be done to protect our children and athletes from becoming at risk for developing this serious and deadly condition.

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