Читать книгу Concussion - Kester J Nedd DO - Страница 9
ОглавлениеConcepts and terms that better define TBI/concussion in the context of the BHET Method
OVER THE YEARS, the pressure to implement well-defined research methodologies combined with our misunderstanding of how the brain works, is injured, and how it recovers has forced us to standardize what many experts believe to be unsound definitions of what a concussion and/or a Traumatic Brain Injury (TBI) is. In fact, we now know that some of our conclusions regarding a brain injury and its impact have been sometimes wrong or misleading. These unsound definitions have caused us to have generations of people with missed cases of concussion and TBI. Imagine playing American Football in the 1960s, 1970s, 1980s, 1990s and even in early 2000. In many cases, you would not be considered to have suffered a concussion or TBI without loss of consciousness (LOC). LOC was a key part of defining a concussion, and this remained the case for many years. While LOC continues to be a factor in the definition, one needn’t have experienced LOC to have suffered concussion or TBI. We now know that most persons who suffer a concussion do not in fact experience LOC. I have seen patients with gunshot wounds to the head with a bullet traversing the frontal lobe of the brain with what we know to be a severe TBI requiring major neurosurgical intervention and yet not have experienced LOC. In a study performed with 343 individuals with concussion, more than 80% did not experience LOC and 95.6% had Glasgow Coma Scale (GCS) scores of 15/15 on presentation to the Emergency Department (ED). A score of 15 represents the best possible score following an injury (Pensford 2019).
A study published by the University of Pittsburgh Medical Center for Sports Medicine determined that only 2 out of 107 athletes with concussion suffered LOC, indicating that approximately 98% of persons with concussion in their program did not suffer LOC. According to Kenzie et al. (2017), LOC during concussion has been evidenced at 14%.
Even today, I hear some of my colleagues in neuroscience say that you must have LOC to be considered as having a concussion or TBI. How sad and uninformed! Several ex-football players who participated in hitting exercises whom I see as patients today tell me that if they did not experience dizziness, spinning sensation, feeling of being in a fog, or daze, they were considered “a softy.” What they did not know at the time is that every time they experienced these symptoms, yet another cerebral concussion was heralded. What we now know is that repeated hits to the head as that witnessed in American Football can lead to long-term consequences, including conditions such as chronic traumatic encephalopathy (also known as (CTE), a form of Dementia commonly seen in athletes with repeated hits to the head (McCrory 2017). Increasingly, data shows that even players with multiple hits to the head who are not considered to have suffered concussion (sub-concussive hits) can suffer long-term consequences such as CTE, a degenerative disorder of the brain caused by TBI and concussion (Moore 2017, McAlister 2017, Gardner 2015, Washington 2016).
Concussion occurs when mechanical forces affect the brain in such a manner that the physiological hierarchical organization and the associated functioning of the brain are disrupted to the extent that the patient experiences signs and symptoms which we now know are characteristics of concussion. These signs and symptoms include the following:
• Physical: fatigue, sleep disturbance, dizziness, spinning sensation, headaches
• Cognitive: mental fog, memory and attentional impairment, word-finding problems, communication problems
• Neurobehavioral: anxiety, depression, panic attacks, low self-esteem, fear, racing thoughts, short fuse, obsessive-compulsive tendencies
At its core, concussion have much to do with an imbalance between energy availability and its utilization throughout the brain or in certain parts of the brain (Giza 2001).
Following concussion/TBI, the delicate hierarchically organized structure of nerve cells or neurons working in an array becomes impaired and disorganized. These structures are responsible for the orderly production of energy to ensure the proper function of the brain. After injury, the brain remains impaired until there is recovery or reorganization of these neurons.
Applying the GCS criteria, approximately 80% of all TBI/concussion cases are classified as mild head injuries (Bazarian 2005, Rutland 2006). Data from various studies have shown that approximately 70–90% of all traumatic brain injuries are considered concussions (Cassidy 2004, Numminen 2011). In most cases, concussion symptoms last for a few days but rarely beyond 10–30 days (McCrory 2013, Broglio 2014).
Patients whose symptoms last for more than 30 days experience more physical, cognitive, and neurobehavioral signs and symptoms (O’Neil 2013, Williams 2015, McCrea 2003, Nelson 2016). When concussion symptoms last longer than 3 months following the initial injury, the condition is labeled as post-concussion syndrome. In this case, there are usually neurophysiological and neuropathological injuries to the brain structures, causing the disorganization and disruption of brain and body cycles, as well as functioning (Silverberg 2011).
Patients with repeated concussions tend to suffer greater long-term effects of concussion and/or TBI.
For the purpose of this book, “concussion” is defined as a milder form of TBI where the patient may or may not experience an alteration in or loss of consciousness for a brief period of time that is generally less than 30 minutes and may have the associated signs and symptoms but no focal neurological deficits. Focal neurological deficits generally involve an impairment in the neurological function of one or more parts of the body after an injury (e.g., weakness on one side of the body). The term “Traumatic Brain Injury” will be reserved for the more severe forms of injury, where there is one or more of the following: significant alteration in or loss of consciousness generally for more than 30 minutes; focal neurological deficits; or abnormal findings on CAT scan or routine MRI related to the injury. Abnormal CAT and MRI scans are rarely seen in concussion, depending upon how concussion is defined in various studies.
Between 5–15% of concussed patients will have trauma-related positive findings on MRI (Ellis 2015, Morgan 2015).
More recent sequences (techniques) in MRI, such as diffusion tensor imaging (DTI), can show abnormal findings in concussion patients that were not previously documented using the CAT scan or the regular MRI sequences (Arfanalkis 2002, Niogi 2008, Wilde 2008).
We now have both anatomic and physiological tools to evaluate one’s brain function after an injury, and while many of these tools are yet in their early stages of development, they tell us quite a bit about how the brain actually works, when an injury occurs, and what happens during recovery. Positron emission tomography (PET) scans and functional MRI (fMRI) are promising, as they look at the metabolism of glucose to reflect the functioning of distinct areas of the brain. The fMRI utilizes cognitive paradigms during imaging to look at the functioning networks and their connections to various areas (nodes) of the brain to determine their relationship while performing certain tasks (Medaglia 2017).
While there are limitations in these methods, they are valuable in the detection of injury and in understanding the patterns of recovery when compared to a normal functioning brain.
Recently, various pronouncements have been made about the identifiable markers of concussion/brain injury, which are found in blood and cerebrospinal fluids and that can be measured in the laboratory following an injury. Undoubtedly, findings such as these will ultimately change the definition of concussion and TBI. What we now know is that the definition of concussion will continue to evolve as we learn more about the science of brain injury.
Note that “traumatic brain injury” or “TBI” and “brain injury” are often used interchangeably to describe all forms of injury, including severe traumatic brain injury and concussion. “Concussion” and “cerebral concussion” are also used interchangeably.
Words and Concepts that Truly Define the Hierarchical Brain
Defining certain concepts and categorically organizing such concepts in a meaningful way to effectuate diagnosis and treatment and predict outcomes is what BHET is all about. While there are various approaches to evaluate and treat TBI/concussion, the BHET method espouses that there can indeed be a right and wrong way to evaluate and treat persons who carry the diagnosis of TBI or concussion.
Structural Anatomy: Relates to the physical structures of the nervous system that are both microscopic (also referred to as histological anatomy) and macroscopic that can be seen with the naked eye (also referred to as gross anatomy).
Physiology: Deals with the biology of how all living organisms work in relation to physical and chemical processes.
Cognitive or Neurocognitive or Neuropsychological Functioning: Deals with the cognitive function of humans that allows us to behave in certain ways that express who we are, what we believe, what is important to us, and how we relate to each other. It involves how we communicate, understand, express emotions, learn, memorize, perceive, process information, and relate to others and the world around us.
Neurobehavioral Functioning: Relates to how we react to who we are, what we perceive others to be, and how we respond to a situation. For example, anger, depression, anxiety, paranoia, and obsessive-compulsive tendencies are more neurobehavioral and can occur as a result of physical and neurocognitive factors, the environment, injury, or genetic defects that impact our physiological, functional, and our structural order.
Psychosocial: Looks at how the psychological factors and the social environment impact the physical health and mental wellness of an individual and their ability to function in society.
The hierarchical approach takes into consideration the following concepts:
1. Understanding the normal working of the brain and the working of the brain following injury – Having knowledge of the normally working brain enables a comparative understanding of the levels of disorganization that occur following injury and the subsequent reorganization that occurs during the recovery process. Anatomical, structural, and physiological disorganization produces a certain symptoms complex. Patients are not only treated according to the level of signs (what the professional finds) and symptoms (what the patient experiences) but also based on an understanding of the anatomical, structural, and physiological disorganization that disrupts the hierarchical order of functioning. This disruption can produce a complex set of symptoms reported by the patient and signs noted by families, caregivers, and through a meticulous evaluation performed by qualified clinicians. In doing so, BHET focuses on determining the level and severity of injury at every stage of the recovery process in terms of the hierarchical organization. BHET utilizes realistic evaluation methods to properly classify those conditions.
2. Treatment Concepts – The simple principles of what to treat first, where to start, how one sign or symptom relates to another, what athe triggers of a sign or symptom are, how to proceed with and when to end a treatment modality, are all critical issues in TBI/concussion. It is essential to establish the order and sequence of administering a treatment modality after the condition has been properly staged and classified. Once the level of disruption is established, there is generally an attempt to match the available treatment modalities to the patient based upon the level established. While the levels cannot always be neatly defined, any effort to classify the disorder into a hierarchy will go a long way towards treatment planning. BHET also provides sensible, logical, and whenever possible consensual and evidence-based tangible treatment modalities that generally produce positive results. This facilitates an approach that determines what should be evaluated and treated in the appropriate sequence and manner for effective recovery. This model utilized to treat TBI has the level of hierarchical organization and reorganization following TBI/concussion as its focus. Addressing those issues utilizing the BEHT method has made the concepts meaningful. Clinicians must resist the urge to start treatment when they have no idea what they are treating but feel the urge to do something because of the suffering reported by patients and their families. Such issues of treatment will be addressed in the second volume of this book series.
BHET provides a framework that can be utilized for making critical decisions about staging, prognostication, and treatment. This book was designed to bridge a significant chasm that exists among the various healthcare professionals and between health professions and the lay public. By taking this very complex area of neuroscience that utilizes case histories and models, BHET makes it easy to understand this complex condition.
A major point of failure with clinicians treating TBI is their limited understanding of the hierarchical organization of the brain before and after injury and the subsequent recovery path that the brain follows during recovery. I have personally seen patients be harmed because of this misunderstanding. In fact, certain treatment modalities are often administered at the wrong time or stage of recovery because of a misunderstanding of the brain’s hierarchal organization and the process by which such disorganization is restored following injury. BHET was developed based on my experience as a neuroscientist working in the field of brain injury with a team of colleagues who I have come to respect and admire. In developing this method, I have been able to utilize my experience in leadership and business, the practice of neuroscience, knowledge of the human condition, and my understanding of how the nervous system works, in order to conceptualize and implement BHET.
