Knockout Head Injuries Linked To Parkinsons But Not Alzheimers
Massive new study turns up surprises on the long-term fallout of unconsciousness-causing brain injuries that occur early in life
There has long been debate about a link between serious blows to the head and the development of neurodegenerative diseases later in life. Research has made cases for and against a relationship between traumatic brain injuries and neurological ailments such as Alzheimers, Parkinsons and general dementia. Now the question is drawing ever more scrutiny as the alarming extent of these injuries becomes better knownand new research is finally casting some light on this murky and often quietly terrifying topic.
A large-scale analysis of three separate studies published this week in JAMA Neurology found no association between unconsciousness-causing traumatic brain injuries and Alzheimers disease or general dementiabut it did find a strong association between TBI and Parkinsons disease. I cant decide if the positive or negative findings are more surprising, says one of the studys investigators, physician and Alzheimers researcher Paul Crane at the University of Washington. The positive association his team found between Parkinsons and TBI was not entirely novel, but Crane says the magnitude of the link was unexpected. The researchers found the risk of Parkinsons rose threefold for people whose head injuries had caused them to go unconscious for more than an hour.
Reasons Why Parkinsons Disease Occurs
The scientific reason given for Parkinsons disease is that the patient has lost nerve cells in the part of the brain called the substantia nigra. A very important chemical called dopamine is produced by the substantia nigra. The loss of the ability to produce dopamine contributes to the early stages of Parkinsons disease.
Difference Between Parkinsons Disease And Parkinsonism
Parkinsonism is an umbrella term used to describe a group of movement disorders that share similar symptoms.
The signs of parkinsonism include:
- Resting tremors
- Difficulty with balancing and walking
Parkinsonism can also cause people to perform uncontrolled, repetitive movements, known as tics.
PD is the most common type of parkinsonism, but there are other types that have more specific causes, such as:
- Drug-induced parkinsonism. This occurs when a person takes a medication that lowers dopamine levels. Symptoms usually disappear once the medicine is stopped.
- Vascular parkinsonism. Stroke can cause certain parts of the brain that control movement to die, leading to Parkinson-like symptoms.
- Post-traumatic parkinsonism. Brain damage to the cerebellum or basal ganglia can also cause movement disorders that look a lot like Parkinsons Disease.
Whether you have PD or some other form of parkinsonism, treatment will mostly be identical.
Age And Genetic Factors Are Not Everything
The rate of Parkinsons disease globally has exceeded far faster than the population has aged according to the American Parkinson Disease Association.
Cases of the disease are up by several multiples over the past decades. From 1990 to 2015, the cases of the disease globally more than doubled, suggesting that there is far more at work. From 2015 to 2040, cases are expected to double once again. This is far higher than the rate of aging in the population.
Pathology Overlap Between Tbi And Pd
TBI sequalae can be divided in to 3 phases: acute , post-acute , and chronic . During the acute period cell necrosis from direct transfer of force to the brain tissue occurs, followed by secondary cell death from axonal pathology, and inflammation. The post-acute period can be characterized by neuronal remodeling, decreased inflammation, and an increase in chronic pathology . Chronic pathology of most interest here includes, neurodegeneration, protein misfolding , and persistent inflammation. Chronic TBI pathology can vary, with some patients recovering completely while others suffer physical and cognitive decline, and eventually develop neurodegenerative diseases , most notably Parkinsons Disease .
PD as well as TBI brains are characterized by neuronal degeneration, compromised blood brain barrier, infiltration and expansion of resident microglia into the affected areas, and infiltration of phagocytic cells from the periphery . In both PD and following a TBI this histological presentation is accompanied by inflammation, metabolic disturbances, and protein aggregation, making them essential factors to consider when studying the mechanisms connecting these two disorders.
Can Head Trauma Cause Essential Tremor
It seems like nearly every day brings some new health issue to be concerned about. If it isnt mosquito-borne disease, its distracted drivers on their cell phones. Then theres head trauma. This was brought to popular awareness by the movie Concussion, based on a real-life story about the doctor who identified extreme brain damage among NFL football players. He called it chronic traumatic encephalopathy , and it ravages a persons brain. A recent news story told how examination of 111 deceased NFL players brains led to the revelation that 110 of them had CTE.
Its a scary, sobering report, yet the movie did not trigger widespread anxiety among us non-athletic types. After all, who among us has an occupation that involves severe repeated brain-battering like hard-hitting football does?
Its easy, therefore, to not include head trauma on our list of daily anxieties, but in fact traumatic brain injury is more common than we think. The U.S. Centers for Disease Control says that everyone is at risk, especially children and older adults in 2013, there were about 2.8 million TBI-related emergency room visits and hospitalizations. The CDC defines TBI as a bump, blow, or jolt to the head that disrupts the normal function of the brain. The injury can range from severe to mild, and most concussions are in the moderate-to-mild category.
Models Of Tbi And Their Application In Pd Research
While no single animal model of TBI will ever recapitulate all features of human TBI, each of the models discussed below can answer specific questions about aspects of human TBI.
Certain mechanistic questions can be best addressed with primary or model neurons in culture. One such method involves growing neuronal cells on a silastic membrane that is then stretched using compressed gas mimicking torsional stress experience by neurons during TBI. This biaxial stretch injury model has been adopted for use in a variety of immortalized and primary cells and has led to a better understanding of primary astrocyte and immortalize neuron cell specific responses to injury . In both studies, cell injury controllers were used to deliver a stretch injury to a monoculture of cells on a silastic membrane. The in vitro studies show that cellular responses are quantifiable and track with severity of injury in both astrocytes and immortalized neuronal cells.
Table 1 Rodent TBI injury models. Controlled cortical impact , Fluid percussion injury , Penetrating ballistic brain injury , and closed head injury weight drop are the most commonly used injury methods
Symptoms Of Parkinsons Disease
If you have slowness on one side of your body, you should see your doctor. This isnt just a symptom of normal aging. However, symptoms of Parkinson’s disease worsen as you age. These symptoms include tremors, stiffness, slow movement, impaired balance, and a shuffling gait. Some patients may feel more stiffness than others. For some, the tremors are more predominant. You may also have a hard time forming facial expressions.
What Is Parkinson’s Disease
Parkinson’s is a neurodegenerative disease in which your brain cells that produce dopamine start to die, which causes you to gradually lose muscle control. No matter your age, Parkinsons can seem like a scary thing, but thankfully, with the right care, the symptoms of Parkinsons can be manageable.
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Anxiety: A Silent Symptom Of Parkinsons Disease
The diseases environmental risk factors include exposure to pesticides, heavy metals, and air pollutants, as well as traumatic brain injury. Pesticides, in particular, have attracted researchers attention as possible Parkinsons triggers.
Given evidence supporting a link between agriculture and Parkinsons, researchers at the Geisel School of Medicine at Dartmouth, in New Hampshire, wondered why Medicare records showed relatively high disease concentrations in both their region of the Northeast and in the Midwest. Between these two regions, agriculture and its related pesticide use is only widespread in the Midwest.
They decided to examine environmental exposures and lifestyle behaviors among people in a rural area of New England with and without Parkinsons.
Identifying environmental factors that increase risk would allow exposure mitigation and disease prevention efforts while facilitating the experimental investigation of mechanisms and intervention opportunities, they wrote.
Investigators conducted a survey of 97 people with Parkinsons, with a mean age of 69.36, and 195 age- and sex-matched healthy individuals in New Hampshire and neighboring Vermont between 2017 and 2020. Respondents were asked about their employment, hobbies, physical activity, exposures to various substances, and family medical histories.
Exposure to lead associated with a 2.7 times greater Parkinsons risk, after adjusting for these same factors .
Traumatic Brain Injury And Parkinsons
For years, the medical community has acknowledged that traumatic brain injury can lead to Parkinsons disease. Now, more experts are beginning to understand exactly how TBI increases the risk of developing this disease.
Our attorneys routinely represent individuals and families of those who have sustained traumatic brain injuries as a result of motor vehicle accidents, workplace injuries, falls, defective products, and more. TBI can lead to a large range of symptoms, depending on the severity of the injury, the location of the injury, and the patient himself. Symptoms can thus range from headaches to permanent cognitive problems and even death.
Researchers at UCLA have isolated a specific neuron in the brain which is lost after a victim suffers a traumatic brain injury. They have further confirmed that the loss of this neuron can trigger the development of Parkinsons disease.
The study found that a moderately-severe TBI can trigger a fifteen percent loss of nigrostriatal dopaminergic neurons almost immediately, followed by an additional fifteen percent loss over the course of the next six months. The researchers also found that a TBI combined with another specific risk factor for Parkinsons exposure to the peticide paraquat this loss can occur far more rapidly.
Nigrostraital dopaminergic neurons participate in the production of dopamine, a substance which in turn helps to regulate movement .
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What Does It Mean
While the CDC considers most TBIs reported annually to be mild, this study found that experiencing a concussion may, in fact, be a substantial risk factor for developing Parkinsons disease and dementia .
Having a single concussion increased the risk of developing PD by 57% and dementia by 72% and having multiple concussions further increased the risk of developing PD and dementia compared to people who suffered only one concussion. While additional studies are surely warranted, this study suggests that concussions should be taken more seriously by healthcare providers, as there may be unanticipated, long-term neurological effects.
What Is Parkinsons Disease
This slow-moving disease harms nerve cells in your brain over time, causing them to slowly die. Most of those affected nerves control and coordinate your bodys movements, triggering Parkinsons disease motor symptoms. As PD progresses, it becomes harder to control muscle movement and coordination. So getting dressed, walking, and other daily activitiesthings that used to be easycan become more and more challenging.
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Do Brain Injuries Increase Long
Even if your senior loved one doesnt show any signs of dementia following a head injury, he or she may not be entirely safe from dementia. Brain injuries are classified as mild, moderate, or severe depending on the nature of the injury. Though a single mild injury isnt associated with an increased dementia risk, a moderate brain injury raises the risk of Alzheimers by 2.3 times, while a severe injury increases it by 4.5 times. Repeated mild brain injuries, such as those experienced by athletes in football, boxing, and hockey, can also result in heightened dementia risks. In addition to being more likely to develop dementia, people with head injuries tend to show signs of dementia at an earlier age than the average population.
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What Causes Parkinsons Disease
Developing Parkinsons disease is not something that often happens on its own. Of course, there are genetic factors that could play a part in this neurological disorder. However, it is a combination of genetic and environmental factors that could lead to this disease.
In some cases, we have seen recent lawsuits that allege that exposure to certain chemicals has caused Parkinsons disease. Here, we will focus on how people could develop Parkinsons. That could give you an idea of whether you may have a possible lawsuit.
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What Causes Traumatic Brain Injury
A TBI is caused by an external force that injures the brain. It can occur when a persons head is hit, bumped, or jolted. It also can occur when an object, such as a bullet, pierces the skull or when the body is shaken or hit hard enough to cause the brain to slam into the skull.
Concussion Associated With Greater Risk Of Parkinson Disease Dementia
Individuals who had experienced a concussion were found to be at a greater risk of Parkinson disease, mood and anxiety disorders , dementia, and hyperactivity disorder, with concussed women indicated as a notable at-risk population for MADs, according to study findings published today.
Individuals who had experienced a concussion were found to be at a greater risk of Parkinson disease , mood and anxiety disorders , dementia, and hyperactivity disorder, with concussed women indicated as a notable at-risk population for MADs, according to study findings published today in Family Medicine and Community Health.
In recent years, the incidence of concussions has steadily increased, the researchers noted, especially among adolescents. Notably, related effects of concussions have been indicated as dysregulation of the autonomic nervous system, cerebral blood flow, and cerebral metabolism.
While these effects may seem troubling, the clinical recovery from concussions typically occurs within the first week of injury. However, the long-term implications of concussions remain unknown.
In previous research, the study authors highlighted that potential associations with increased risk of attention-deficit hyperactivity disorder , depression, anxiety, dementia, and PD are limited by study design factors such as a reliance on self-reported medical history and the inclusion of all forms of traumatic brain injuries.
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What Are Common Symptoms Of Traumatic Brain Injury
TBI symptoms vary depending on:
- The type of injury
Just One Concussion Could Raise Parkinson’s Risk
“Upwards of 40 percent of adults have had a traumatic brain injury , so these findings are definitely concerning,” said study author Dr. Raquel Gardner. She is an assistant professor of neurology at the University of California, San Francisco, and the San Francisco VA Medical Center.
But Gardner stressed that the findings don’t mean everyone who has ever had a concussion is doomed to develop the degenerative neurological disorder that affects coordination of movement.
“Even in this study, the vast majority of veterans with traumatic brain injury did not develop Parkinson’s,” she said.
Dr. Rachel Dolhun, vice president of medical communications for the Michael J. Fox Foundation for Parkinson’s Research, pointed out the lifetime risk of Parkinson’s is probably about 1 to 2 percent, so a greater than 50 percent increase in that risk isn’t as alarming as it sounds.
“Having a TBI doesn’t definitively equate with getting Parkinson’s disease. The risk is still pretty small,” Dolhun said.
But these findings do lend credence to the idea that some professional athletes have developed Parkinson’s disease as a result of their athletic careers. The most famous is probably boxer Muhammad Ali.
Study volunteers were aged 31 to 65, and were followed for up to 12 years.
Concussions May Increase The Risk For Parkinsons Disease
A traumatic brain injury, even a mild concussion, increases the risk for Parkinsons disease, a new study reports.
Researchers identified all patients diagnosed with T.B.I. in a Veterans Health Administration database 162,935 men and women and matched them with the same number of people with similar health and behavioral characteristics but who had not had a brain injury. The study is in Neurology.
Of the T.B.I. cases, half were mild, involving a blow to the head with some subsequent symptoms but with little or no unconsciousness. The rest were moderate to severe, involving extended unconsciousness or long-term symptoms.
After controlling for age, race, income and many medical and psychiatric diseases, they found that compared with those who had had no T.B.I., those with a mild T.B.I. had a 56 percent increased risk for Parkinsons disease those with moderate to severe T.B.I. had an 83 percent increased risk.
We dont have brain autopsies, so we dont know what the underlying biology is, said the lead author, Dr. Raquel C. Gardner, an assistant professor of neurology at the University of California, San Francisco. But in Parkinsons you see abnormal protein accumulation, and theres some evidence that T.B.I. is linked to deposits of these abnormal proteins.
In any case, she said, This study provides the most definitive evidence that there is this association.