Introduction
Traumatic brain injuries, such as concussion, may have a serious impact on an individual’s health and cognitive functions. Recently, scientists have reported the link between this type of injury and various neurodegenerative disorders. Alzheimer’s disease is a significant condition that may develop in individuals with a history of concussions. It is associated with irreversible effects on the patient’s brain, as well as changes in behavior, memory loss, and problems with cognitive functions.
These symptoms show that it is necessary to study the link between concussion and AD. This paper presents a discussion on the existing evidence of this connection. It analyses concussion and AD, presents their causes and symptoms, as well as the challenges associated with these conditions. Then, the report reviews the literature on the topic of discussing the relation between mild brain injury and AD. The paper shows several viewpoints on the issue based on the findings of recent studies. The research also presents a reflection of the analyzed data and discusses its implications. It concludes that there is significant evidence linking concussion to AD that should be considered to develop prevention measures and improve patient outcomes.
Concussion
A concussion is a serious condition that should be studied in detail before analyzing its relation to AD. It may be caused by a blow to a head, face, or neck and can affect many aspects of an individual’s behavior, resulting in poor memory, a lack of coordination and balance, as well as inability to speak properly and use judgment. A concussion is a type of a mild traumatic brain injury that correlates with unfavorable changes in brain function, including the loss of consciousness and the incidents of mental health problems (American Association of Neurological Surgeons 2018).
This condition is associated with several symptoms, such as dizziness, prolonged headaches, nausea, memory loss, problems with balance and concentration, vomiting, loss of smell, and light sensitivity (American Association of Neurological Surgeons 2018). There are approximately 4 million cases of concussion registered per year globally (Galetta et al. 2016). Although a single concussion may not cause permanent damage to the brain, every case of the injury can result in health-related problems in the future. The evidence demonstrates that mild brain injuries can be treated successfully but may be associated with the progress of neurodegenerative disorders in the future, such as AD, which will be discussed below.
Alzheimer’s Disease
AD is one of the most typical forms of dementia, which is related to 60% to 80% of all cases of the disease (Cummings et al. 2015). The symptoms of the condition are memory loss, behavioral changes, and problems with language, cognitive, and executive functions. With time, patients having AD become unable to communicate and need help with daily activities and full-time assistance. Cummings et al. (2015) report that AD is a significant problem for patients and their families, as well as the society and the healthcare system. Many individuals that live with the disease believe that there is no possible solution for their condition and experience stress and depression; often they need full-time assistance with daily activities and cannot be left alone, which may lead to a poor emotional state.
Another significant challenge for the management of the disease is that there are stigma and negative associations related to AD both among the public and medical professionals. Because of that, many individuals living with the disorder may feel that people avoid interacting with them and feel lonely. In addition, the disorder has several stages; during the first one, the patient may show no symptoms while neuropathological changes already exist. The middle phase may be present for many years and require a great level of care. Finally, the last stage is emotionally and physically challenging as it is associated with serious changes in the brain.
Liu et al. (2015) report that early and accurate diagnosis is vital for the disease to decrease the risk of serious health problems associated with it. There are many diagnostic classifications available; they aim to evaluate the individual’s cognitive skills, changes in behavior and personality, and the person’s ability to perform daily activities. A medical professional may perform neuropsychological assessments, mental health testing, MRI, computerized tomography (CT), and laboratory tests.
It may also be necessary to interview the patient’s family members and friends to analyze the changes in the individual’s thinking skills and functional abilities. Currently, the condition is considered incurable; scientists are studying the factors that can lead to its development. Many recent and classical studies show the link between concussion and AD. This report will review the existing literature on the topic to explore how these conditions are related. The objectives of this paper are to discuss the evidence of the link and show that concussion increases the individual’s risk of developing AD.
Review of Existing Evidence
Traumatic brain injuries have long been associated with many neurodegenerative diseases, including AD. Gardner and Yaffe (2015) report that there is serious epidemiological evidence that there is a link between these conditions. It is necessary to mention that concussion is not the only risk factor for AD but increases the chance of developing the disease significantly. Gardner and Yaffe (2015) note that the symptoms of this type of traumatic injury are the processes that happen in the brain that are similar to AD.
The study suggests that the link between concussion and this neurodegenerative disorder has been studied since the middle of the twentieth century; the issue gained significant public attention in 2005 after a professional American sportsman reported a serious brain injury. Gardner and Yaffe (2015) report that genetic predisposition combined with head injuries leads to an increased risk of developing AD.
The study by Talavage et al. (2014) is notable as it shows that concussion may have a long-term effect on the individual’s brain. The investigation shows that many people do not recognize the symptoms of a mild traumatic brain injury or prefer not to report them as they do not realize the importance of the condition. As a result, the negative impact on their cognitive and physiological functions increases, which can lead to the development of AD. Talavage et al. (2014) report that in some cases, a concussion may only be revealed during the functional magnetic resonance testing (MRI). The findings of the study suggest that many people are at risk of developing neurodegenerative disorders, such as AD, because of head traumas; many of them may be unaware of this risk.
The study by Julien et al. (2017) shows that traumatic brain injuries, including concussion, are associated with various physical and behavioral consequences, as well as functional difficulties. The more serious an injury is, the worse impact it has on a human. The study shows that currently, more than 35 million individuals in the world have AD (Julien et al. 2017). The risk factors related to the condition include moderate and severe brain injuries in an individual’s early or middle life. The study shows that a brain injury that led to the loss of consciousness is a significant factor that can lead to AD at an early age. Moreover, the later the traumatic brain injury occurred, the worse patient outcomes may be.
The research by Esopenko and Levine (2015) supports this point of view. The authors note that individuals are at risk of developing AD if they have a history of concussion. The study shows that traumatic brain injuries make brain structure different and cause various abnormalities that lead to behavioral and cognitive changes in adults. Esopenko and Levine (2015) report that the age at which an individual experienced concussion is important; children are at a higher risk of developing AD in the future that those who had a brain injury at an older age.
The possible reason for it is that brain plasticity increases with age. Notably, people having a concussion at 40 years of age or later may have worse and more long-term health outcomes (Esopenko & Levine 2015). It means that traumatic brain injuries have a different impact on individuals across their life cycles. The study also suggests that a single concussion is unlikely to lead to AD unlike the repetitive traumatic brain injury but increases the risk of developing the disorder.
The study shows that there is no significant evidence of the effect of a person’s sex and the risk of development of AD after a concussion. At the same time, women have a higher prevalence of mild brain injuries and usually recover slower than men (Esopenko & Levine 2015). The reasons for it may include differences in neck strength, sporting environment, blood flow, and hormones. Currently, it is unclear whether sex may increase the individual’s risk of AD but the existing data should be taken into consideration.
The link between concussion and AD is also presented in the study by Sundman, Hall, and Chen (2014). The authors note that traumatic brain injuries often result in unconsciousness, coma, amnesia, and other serious conditions. A concussion is the most common form of such damages and is one of the dominant causes of morbidity (Sundman, Hall & Chen 2014). The study shows that although concussion may be related to many neurodegenerative diseases, the strongest evidence shows the link between this type of head injury and AD.
Sundman, Hall, and Chen (2014) present the evidence found in fifteen case-control studies, which show that individuals with a history of concussion are 60% more likely to develop the disorder compared to those who have had a brain injury; moreover, it may speed up the development of the condition.
The evidence that there is the link between concussion and AD is that both of them are associated with plaque disposition, which can be seen in individuals that had a fatal traumatic brain injury (Sundman, Hall & Chen 2014). In addition, the study suggests that there is an increasing epidemic of neurodegenerative diseases as a result of brain damages. Although these disorders have many components and risk factors that should be considered, concussion and other traumatic brain injuries may play a significant role.
Some of the studies that include a literature review also report that head injuries, including concussion, can lead to an increased risk of AD. For example, Li et al. (2017) present the analysis of 32 studies that involve more than 8,000 cases of the disorder. The authors report that individuals were more than 50% more likely to develop AD after a traumatic brain injury compared to those that did not have a concussion (Li et al. 2017).
The data included in the study were collected during the past two decades, which means that the link between the two conditions has been a significant concern for scientists. The authors note that the findings of the researches show stability in a sensitivity analysis. Li et al. (2017) report, however, that some retrospective studies included biased opinions. The research concludes that there is a link between concussion and AD even in cases where the loss of consciousness was not observed.
It is necessary to note that some studies show that the link between concussion and AD maybe not as evident. For example, Faden and Loane (2015) note that AD is only one of several neurodegenerative disorders that may be caused by traumatic brain injuries and other types of dementia may have a stronger association with the concussion.
The study shows that AD is associated with amyloid and β-amyloid plaques, while concussion may cause an increase in amyloid levels and lead to their deposition, which shows that these conditions are related (Faden & Loane 2015). However, the study shows that in more than 45,000 participants, AD was not related to mild or severe brain injuries and was caused by other factors. At the same time, the history of concussions was, reportedly, a considerable risk factor for the development of dementia, but not AD specifically (Faden & Loane 2015).
Reflection on the Existing Data
The findings of the reviewed articles show that there is a link between concussion and AD. People who have a history of traumatic brain injuries are commonly at risk of developing the disease in the future. There are some potential reasons for it; they include the similarities in the brain changes associated with concussion and AD, the brain abnormalities that happen after brain injuries, and the plaque disposition that is seen in both AD and concussions.
It is necessary to mention that although many findings present the direct connection between these two conditions, some evidence suggests that mild brain damages are more likely to lead to other types of dementia, rather than AD. However, the majority of the reviewed studies show that concussion is a serious risk for the development of the disease. The existing literature suggests that although concussion is considered a mild condition, it can, as other types of traumatic brain injuries, lead to neurodegenerative disorders.
The existing studies reveal that there are many factors that should be considered while studying the link between AD and concussion. The findings show that the age, at which a mild traumatic injury occurred, may play a great role in the development of the condition. However, this data may present challenges for the researchers as the risks do not increase with the person’s age but are higher in the early childhood and adulthood. Moreover, the individual’s sex may be considered a potential risk factor that increases their ability to develop AD after a concussion.
The evidence also shows that the link between concussion and AD has been analyzed for many years and recent studies confirm the interrelation between the condition. The researches on the topic are published in both peer-reviewed journals and newspapers, which means that the problem has become a public concern (Donnelly 2018). Various sources discuss concussion and AD, presenting the symptoms of both conditions, the risk factors associated with them, and the number of people affected by them. This fact proves the significance of the research on the link between mild brain injuries and neurodegenerative diseases.
As mentioned above, some studies reported that there was no significant link between concussion and AD compared to other related disorders. This issue should be addressed as it shows that some scientists may not consider the existing evidence reliable. It means that it is necessary for researchers to continue analyzing the problem and perform studies that include a larger number of participants with a history of a single and multiple concussions. Moreover, it is also important to involve adults having an AD that had had no other significant risk factors before developing the disorder.
Implications of the Findings
The findings related to the link between concussion and AD may be used to develop an approach to the prevention of the condition. It is vital to concentrate on the elderly as they are at high risk of both falling and having a traumatic brain injury and developing AD because of their age (Becker, Kapogiannis & Greig 2018). People that are involved in sports and intensive physical activities are also at risk, as they may have a head injury. Studies show that, in some individuals, the symptoms of the disease appear within two years after a concussion, which means that it is crucial to take necessary measures to prevent its development (Becker, Kapogiannis & Greig 2018).
There are many steps that can be taken to avoid the development of AD caused by a traumatic brain injury. First, for people playing contact sports, it is necessary always to wear helmets to decrease the risk of a head injury. It is also important to wear a helmet when on a motorcycle and similar vehicles, as well as riding a horse, skating, snowboarding, and skiing. Many individuals do not realize that they are at risk of having a concussion during daily activities and rarely use protection, which leads to many cases of traumatic brain injuries.
Second, it is necessary to wear a seatbelt in a car, even if sitting in the back seat; for children, it is important to use a child seat. Unfortunately, many adults do not follow this rule as they think that they can drive slowly to avoid car incidents, which is a wrong belief. Finally, people should never drive after drinking alcohol or taking drugs. These measures may seem unnecessary and unlikely to play a critical role in the prevention of concussion but all of the mentioned factors are important in increasing the risk of a neurodegenerative disorder.
To prevent the development of AD caused by falling, which may be the case for elderly people, the following prevention methods should be used. First, it is important for older individuals to use the rails on the stairways, especially when they have difficulties with walking. Second, people that have a poor vision should have adequate lighting in their houses, especially on stairs; windows should have bars to prevent individuals from falling. Many older individuals often ignore this measure as they do not realize its significance and possible negative impact on their health. Finally, it is necessary to sit only on safe chairs that are not broken or damaged. These measures can lower the risk of falling and having a brain injury.
The findings of the study also show that it is necessary to continue studying the connection between concussion and AD as, currently, researchers have not fully agreed whether there is a direct link between them. At the same time, traumatic brain injuries continue to pose a serious threat to individuals and may result in unexpected health outcomes in the future. In addition, as mentioned above, both concussion and AD are related to the disposition of amyloid and β-amyloid plaques. It means that the research of this link may potentially help to find a cure for AD and study other factors that may increase individuals’ risks related to it, including the genetic ones.
Summary and Conclusion
This report revealed that there is an evident link between concussion and AD. A concussion is a mild brain injury that may result in short- and long-term changes in the brain, and can lead to an increased risk of AD development. The review of the existing literature showed that there were several factors supporting the link between these conditions. First, both AD and concussion are related to the changes in amyloid and β-amyloid plaques.
Second, they may be associated with similar processes in the brain. Third, a significant number of individuals living with AD had a history of concussions in the past. It is necessary to mention that although the majority of the existing studies show the evidence between a mild brain injury and AD, some of them suggest an alternative opinion. This report presented findings that suggested that the link between concussion and other types of dementia are stronger compared to AD. The study, however, notes that concussion and this neurodegenerative disorder are related.
The findings of this report can be used to develop prevention measures for AD and brain injuries. Individuals should be cautious while driving and engaging in physical activities. For the elderly, which are at high risk for concussion, it is important to take measures that can prevent falling. In addition, the study may be used for educational purposes as it presents a summary of many analyses on traumatic brain injuries and AD.
The primary strength of the presented study is that it reviewed global evidence from peer-reviewed journals and included a large number of researches in the field. It introduced the existing findings on the topic, including those that may have an alternative opinion, and discussed the factors that support the link between the conditions. The possible limitation is that many of the reviewed studies have included a limited number of participants and concentrated on those who had a concussion-related to sports. However, the report showed significant evidence of a link between concussion and AD, suggesting that it is vital to continue studying the topic to increase the risks of developing the disorder for the population.
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