Even a mild head injury, commonly referred to as concussion, makes veterans more likely to develop Parkinson's later, a new study shows. This is the same kind of injury that many Americans endure on the sports field or in a car accident every year.
A group of 165,000 veterans with Traumatic Brain Injury (TBI) had a higher risk of Parkinson's disease compared to other veterans of the same age.
The link between a serious head injury and Parkinson's disease was already known, but the key finding was that even minor head injuries could increase that risk. Half of the veterans in the study had only a slight head injury, and this group was 56 percent more likely to receive a Parkinson's diagnosis than those without TBI. The risk increased more in persons with a severe head injury.
"This is the highest level of evidence to prove that this connection is a true and serious connection." Raquel Gardner, senior author of the study and assistant professor of neurology at the University of California, San Francisco (UCSF) and the San Francisco VA Medical Center, said ABC News.
Overall, Parkinson's is still very rare.
"Even in our study, the vast majority of veterans who had traumatic brain injury [more than 99 percent] did not have Parkinson's disease, so the risk is low at the individual level," Gardner said.
What is the connection?
It could be explained by the release of a protein called "alpha-synuclein" by injured brain cells into the fluid surrounding the brain. An abnormal accumulation of this protein in cells is a feature of Parkinson's disease. But much more research is needed to better understand the effects of brain injury.
"The TBI could directly trigger changes in the brain that were not there before, the other possibility is that a process may have already occurred in the brain and the person may have had Parkinson's disease [anyway] many years later Brain injury caused symptoms to start earlier and the diagnosis came earlier, "Gardner explained. "We need more studies to decipher the biology behind it."
The study was published Wednesday in the online edition of the Journal of Neurology. This study is part of the large research initiative "Chronic Effects of the Neurotrauma Consortium". One of the researchers is senior author Kristine Yaffe, a professor at the UCSF Departments of Neurology, Psychiatry, Medicine and Epidemiology and Biostatistics. The aim of the study is to understand the chronic effects of TBI – particularly mild TBI – in veterans, and it is a response to the high rates of mild TBI in young veterans.
"While the participants all served in the active military, many, if not most, of the traumatic brain injuries were acquired in civilian life," Yaffe said in a press release. "We believe that this has important implications for the population."
About Parkinson's Disease
Parkinson's is a chronic, progressive disease of the brain that causes problems with balance and movement. People often develop tremors or very slow, stiff movements that eventually lead to difficulty walking or doing simple tasks. The symptoms usually develop gradually.
Researchers are still working to understand what causes Parkinson's. It's probably a combination of genetics and brain changes throughout the lifetime. Parkinson's usually occurs in adults over 60 years. There is no cure for the disease, but therapies can slow the progression of motion symptoms. Currently available treatments include drugs that affect brain signaling, and a process called deep brain stimulation, in which electrodes are implanted into the brain.
Visit the American Parkinson Disease Association website to learn more about Parkinson's disease.
The Centers for Disease Control and Prevention (CDC) describe a TBI as "a disruption of normal brain function that can be caused by a shock, blow or jerk on the head or piercing head injury."
TBI is gaining increasing attention as a public health problem in the US. They contribute around 50,000 deaths per year, but there are also concerns for people surviving their head injuries.
After SHT, memory disorders, abnormal vision or hearing, balance problems or communication difficulties may occur. They can also have emotional changes such as anxiety, depressed mood, aggression or even social inappropriateness. If the injury is a concussion, the symptoms usually disappear within six weeks. Some people experience post-concussive syndrome, which is a prolonged period of difficulty, daily tasks due to symptoms such as headache, dizziness, irritability, difficulty concentrating and slowing down thinking.
Having more than one head injury in a short span of time can be very dangerous. Chronic traumatic encephalopathy (CTE), made famous in the film "concussion", is a specific type of brain disease that can arise after TBI or after many repeated light blows to the head.
Long-term concussion-related problems are very rare, but it has been shown that TBI increases the risk of Alzheimer's, ALS (or Lou Gehrig's syndrome), depression, and bipolar disorder. In most of these cases, brain injury is probably not the only cause of the disease, but is one of many factors, such as genes, lifestyle habits and age, all of which help to make a person more prone to the associated brain changes.
Athletes and military personnel are at high risk for TBI. There is a growing awareness that very young children and the elderly are often affected by a fall in TBI. Car accidents are also a major cause of TBI.
Protecting you and your loved one from TBI
The best way to avoid the consequences of TBI is to minimize the risk of head injury in the first place.
Wear a properly fitted helmet each time you engage in a high-risk activity. This includes riding a bike, scooter, skateboard, or all-terrain vehicle, playing a contact sport such as football or ice hockey, or any activity with the possibility of fast falls, such as skiing, climbing, or horseback riding.
Buckle up every time you drive in a vehicle. If you have small children, make sure the car seats are properly installed.
Family members can help older people to find a safe home by ensuring that there is good lighting in corridors and staircases, using non-slip mats in the shower and bath, and avoiding tripping hazards such as carpeting or power cables from the floor.
If you have small children, install barriers at the top and bottom of each stairwell and make sure that the playing surfaces are made of soft material.
For more information about these security tips, visit the CDC website.
And if you or a loved one suffers a concussion, the best you can do for recovery is rest, quiet, and more rest.
Kelly Arps is an internal medicine resident at Johns Hopkins Hospital. Kelly is working with the ABC News Medical Unit.