Researchers said in a statement that people who had concussions should be aware of the increased dangers of continuing high-risk sports or work.
“We know that head injuries are a major risk factor for dementia and this large-scale study gives the greatest detail to date on a stark finding – the more times you injure your brain in life, the worse your brain function could be as you age,” said Vanessa Raymont, MSc, lead investigator and a senior clinical researcher at Oxford Neuroscience.
“Our research indicates that people who have experienced three or more even mild episodes of concussion should be counseled on whether to continue high-risk activities,” she added. “We should also encourage organizations operating in areas where head impact is more likely to consider how they can protect their athletes or employees.”
Participants reporting three episodes of even mild concussion had significantly worse attention and ability to complete complex tasks. Those reporting four or more mild concussion episodes also showed worsened processing speed and memory.
Researchers linked each additional reported concussion to progressively worse cognitive function.
Even one moderate-to-severe concussion was associated with worsened attention, completion of complex tasks, and processing speed capacity.
Experts told Healthline we still don’t know everything we need to know when it comes to concussions.
Time and staying away from activity that caused the brain injury may be the best healers.
“There is a correlation between healing between concussions and the severity of the injury and timing of recovery,” Dr. Kate Labiner, a pediatric neurologist at Pediatrix Child Neurology Consultants of Austin, Texas, told Healthline.
“The second hit theory is based on the idea where a second head injury is sustained before the prior injury has healed,” Labiner said. “An athlete is injured in a game and continues to play then sustains another hit. This has been shown to prolong recovery.”
Labiner said that’s why it’s important to pull athletes from a game, for example, as soon as there’s any type of head injury, and immediately put them through a protocol to assess the possibility of concussion.
“The most important factor in concussion management is recognizing the injury and completing healing prior to returning to activity,” Labiner said. “The return to play protocol is a step-wise increase in activity with the need to be symptom-free — no headaches, dizziness, light sensitivity, etc. — prior to going to the next step.”
Another factor is everyone doesn’t respond the same to head trauma.
In addition, symptoms can also be caused by other factors such as people without head trauma who have migraine headaches.
“A lot of information is still needed on the long-term effects of completely healed concussions versus post-concussive syndrome,” Labiner said. “We do not know the effect of healed concussion long-term, although we do know there is potential for residual effects, typically cognitive, even in healed concussions. The main importance is healing after the injury before putting oneself at risk for another injury.”
Dr. Huma Sheikh, a neurologist and chief executive officer of NY Neurology Medicine in New York City, told Healthline that a person’s ability to heal from concussions varies.
Much of it also depends on the severity of the impact, which can be difficult to gauge.
“The type of injury and severity of the concussion also play a factor in how much of a lasting impact it will have,” Sheikh said. “There is some evidence that neurons involved in the concussion can try to heal themselves, but this is quite variable.”
Sheikh told Healthline how long damage lingers can come down to that person’s ability to heal.
“Some people who have a genetic predisposition to migraine may have worsening of their migraine attacks after a concussion,” Sheikh said. “This could be possible due to a concussion in the past that may not have had prominent symptoms at the time that they occurred.”
Sheikh said there’s still a lot to sort out, especially when it comes to treatment.
“We used to ask patients to take some time off of work to give the brain some rest after a concussion, but this is not so clear now,” she said. “We do not have any real medications to help a brain recover from a concussion top prevent ongoing damage.”
Arianna Kaminski of New Jersey told Healthline she suffered a concussion years ago during high school gym class, when she was struck by a basketball. She later went to the hospital after having trouble speaking.
Doctors diagnosed her with a minor concussion, told her to stay home for a couple of days, and the symptoms should go away. When they didn’t, she got an MRI that showed everything was “normal.”
Kaminski didn’t feel normal and would get carsick, have light sensitivity, and other symptoms that took her through a variety of therapies, all of which made things worse.
She couldn’t study, which she said has affected her career options. The side effects from medication also took a toll.
Kaminski is now 24 and still experiences symptoms, though not as serious.
“I started to get better when I took my healing into my own hands,” she said. “I started very, very gradually building up my endurance level, eating healthier, exposing myself to controlled light and sound in a way I could handle. I started listening to my body and giving it what it needed: rest, energy, and simple tasks.’
“Over the years, I improved slowly,” she said. “Even now I am sensitive to changes in my environment, including sounds, smells, and lighting, and I often have migraines and neck/shoulder pain. I have dizziness and problems with my eyes.”
Kaminski – who never had migraine headaches before her injury — said her doctors still don’t have answers.
“Some doctors are astounded that I am still exhibiting symptoms this many years later, while others are not surprised,” she said.