Brain Damage from Mild Concussions Seen Months After Symptoms Gone

New research further highlights the continuing effects of concussions, finding that even mild injuries may cause evidence of brain damage long after all symptoms of the concussion have subsided.

In a study published online by the medical journal American Academy of Neurology on November 20, researchers found that individuals who sustained mild concussions showed brain abnormalities four months later, even after they were no longer experiencing symptoms of any problems.

Researchers looked at 50 people who sustained a mild concussion and 50 healthy people with no concussion. Participants were of similar age and educational background.

Special brain scans were conducted after the patients sustained the concussion, two weeks after the injury and then again four months later.

The brain scans continued to show abnormalities four months after the concussion. At that time, the initial concussion symptoms had subsided, leading doctors to believe there was no further risk until examining the results of the scans.

Participants were given tests two weeks after the concussion for memory, thinking skills, anxiety and depression. Four months later, tests and scans were repeated on 26 patients who sustained concussions and 26 who had not.

The test found that two weeks after injury, people who had a concussion experienced more self-reported problems with memory and thinking, along with physical problems, like headaches and dizziness. These patients also experienced more emotional problems relating to depression and anxiety than those who did not have a concussion.

Patients with mild concussions also showed abnormalities in the gray matter in the frontal cortex of both sides of the brain. The scans, done by diffusion tensor imaging, revealed a 10% increase in abnormalities compared to the scans of the injury free participants.

Andrew R. Mayer, PhD, and a team of researchers found recovering from a concussion is similar to recovering from other body ailments, for example a burn.

“During recovery, reported symptoms like pain are greatly reduced before the body is finished healing, when the tissue scabs,” said Mayer. “These findings may have important implications about when it is truly safe to resume physical activities that could produce a second concussion, potentially further injuring an already vulnerable brain.”

While traditional CT and MRI imaging scans do not pick up on the changes in the brain found in this study, Mayer warns it can “lead to misperception that any persistent symptoms are psychological.”

Researchers found most symptoms were reduced by up to 27% four months later, however, significant trauma to the brain was still a factor.

“These results suggest that there are potentially two different modes of recovery for concussion, with the memory, thinking and behavioral symptoms improving more quickly than the physiological injuries in the brain,” said Mayer.

Authors suggest possible explanations include changes to the fluids in and around brain cells or change in cell shape in response to damaged central nervous system. No evidence of cellular loss was revealed on the scans.

Concussion Brain DamageConcerns

The results of the study fall in line with conclusions drawn from other studies published within the last year.

Researchers from the University of Mexico reported in January, when children suffer a concussion, side effects may last for months. They found brain scans revealed white matter in children who suffered concussions continued to change months after the injury and other symptoms disappeared.

A study published in March in the journal Radiology found brain damage may occur after a person suffers only one concussion, even if the severity is thought to be mild.

Concern over the results of studies like these continues to grow, especially factoring in attention surrounding high profile cases of concussion in the media. The cases point to long-lasting side effects, including depression, aggressive behavior, Alzheimer’s and dementia.

A study conducted by the Institute of Medicine and the National Research Council revealed concussions may pose a greater risk to young athletes than originally believed. Researchers found athletes who have sustained a concussion and return to play sooner than recommended may risk suffering a second more severe brain injury. Undergoing a second concussion may result in more severe consequences than the first, considering the brain has not had adequate time to heal properly.

To that end, the American Academy of Neurology issued new concussion guidelines in March, which advise athletes who have sustained even a mild concussion, to leave the game immediately. The AAN guidelines also recommend the player remain out of the game until a doctor trained in concussion management completes a full assessment.