Today, AUC Professor of Physiology and Neuroscience Raymond Colello schools us on brain injury — a topic relevant to every person on the planet.
The brain controls breathing, emotion, hunger, memory, motor skills, temperature, thought, touch, vision, and every process that regulates the body.
Brain injury can affect any or all these functions, so it’s important to know the basics. Dr. Colello helped us out by answering our most pressing questions — and Dr. C knows a thing or two about brain injury: his work helped the National Football League improve helmet safety.
Q: What are some general causes and symptoms of brain injury?
Dr. C: Broadly speaking, brain injury can be caused by stroke (ischemic or hemorrhagic), tumors, degenerative diseases, hypoxia/anoxia, infections, degenerative diseases, and trauma.
The leading causes of traumatic brain injury fall into several categories: falls (the most common), struck by/struck against incidents, traffic accidents, assault, and the broad “other or unknown” category.
The symptoms of traumatic brain injury vary based on severity and can be physical, cognitive, or emotional. They range from headaches to chronic pain, from difficulties in concentrating to mood swings, or from amnesia to a loss of consciousness.
Q: How are traumatic brain injuries defined? What are the main types?
Dr. C: Traumatic brain injuries (TBI) are defined by their severity as mild, moderate, or severe based on five criteria: the time frame in which consciousness is lost; the extent of alteration of consciousness/mental state; the extent of post-traumatic amnesia; structural imaging; and the Glasgow Coma Scale, the most widely used tool for assessing the level of consciousness after TBI.
Q: How is brain function affected by injury?
Dr. C: We perceive our environment through our special senses (sight, hearing, touch, taste, and smell) and act on those perceptions by generating a movement, expressing an emotion, or storing this information as a memory.
All of this is done by the brain’s roughly 100 billion neurons, which are connected to form functional circuits. Brain injury disrupts these circuits by damaging neurons, which are the functional units of the nervous system, or by damaging the axon (the communicating end of the neuron), which makes synaptic connections with other neurons to transmit sensory or motor information.
After neurons or axons are damaged, their functionality is lost. For example, if neurons are damaged in the motor cortex through a stroke, muscle weakness or paralysis occurs.
If axons are damaged in the optic nerve, which conveys visual information to the brain, blindness occurs in the corresponding eye. Damage to cerebral hemispheres or the brain stem (the structure that connects the spinal cord to the cerebral hemispheres) can cause a loss of consciousness.
Q: Do brain injuries affect people differently at different ages?
Dr. C: The simple answer is yes. In the past, researchers proposed that the ability of the young brain to reorganize its structure and connections in response to intrinsic and extrinsic stimuli (plasticity) was superior to the adult brain and, therefore, conferred protection to it following brain injury.
However, recent studies suggest that this is not the case and that injury to a child’s brain is more damaging than a similar injury to an adult. This is likely because many of the neural circuits that control executive functions — such as attention, reasoning, problem-solving, and emotional regulation — are housed in the frontal lobes of the cerebral cortex, which doesn’t completely develop until a person reaches their early 20s.
Consequently, brain injury to this region at an early age can limit brain development, thereby compromising the function of this crucial area of the brain. Not surprisingly, the United States National Institutes of Health (NIH) lists traumatic brain injury as one of the leading causes of disability and death in children and adolescents in the United States.
Q: Are certain people more likely to be affected by brain injury?
Dr. C: Yes, certain demographic groups may be more susceptible to brain injury due to various factors, leading to health disparities. These factors can include socioeconomic status, access to healthcare, occupational hazards, lifestyle choices, and preexisting health conditions.
For example, lifestyle choices such as participating in contact sports and other risky behaviors can increase the likelihood of sustaining a brain injury. Also, disparities in access to healthcare can result in delayed diagnosis and treatment of the condition.
Moreover, individuals with such preexisting health conditions as epilepsy, cerebral palsy, or neurodegenerative diseases may be more vulnerable to brain injury or experience more severe consequences following an injury because of compromised neurological function.
Q: Why is concussion education so important?
Dr. C: First, let’s define concussion. A concussion, also known as mild traumatic brain injury, is caused by a blow, force, or jolt to the head that jars the brain.
Individuals with a concussion can experience a range of symptoms, including headaches, cognitive challenges, difficulty managing emotions, and sleep disturbances. Interestingly, research shows that someone who has already received one concussion is one to two times more likely to receive a second concussion.
Moreover, for each additional concussion, the amount of time needed to fully recover increases and the force required to cause a concussion decreases. Concussion education, particularly in the school setting, is important in promoting safety, early intervention, proper management, and long-term well-being for individuals who may be at risk of or who have experienced a concussion.
Q: How are brain injuries diagnosed and treated?
Dr. C: This all depends on the extent of the injury. For example, mild traumatic brain injuries, as characterized by a loss of consciousness for less than 30 minutes, usually require no treatment other than rest and pain relievers to treat the headache.
The treatment for moderate traumatic brain injuries, as characterized by a loss of consciousness from 30 minutes to 24 hours, first focuses on making sure the individual has enough oxygen and an adequate blood supply and preventing further damage by immobilizing the head and neck.
Individuals who have experienced a severe traumatic brain injury, as characterized by a loss of consciousness for greater than 24 hours, need a combination of intensive medical treatments to ensure an adequate oxygen and blood supply, reduce inflammation, reduce pressure inside the skull, etc. Unfortunately for some people, moderate to severe traumatic brain injury — if survived — can lead to a lifetime of physical, cognitive, emotional, and behavioral changes.
Q: How long is the recovery period for certain brain injuries?
Dr. C: Depending on the severity of the injury, recovery time for TBI varies from days to years. For mild TBI, studies have shown that most people recover most or all brain function within three months, with most recovering sooner.
For moderate to severe TBI, the outcome is more variable, ranging from full recovery to death. Nevertheless, a recent study in JAMA Neurology showed that many people achieved favorable outcomes over the course of their first year of recovery, moving from deep coma to being able to live independently for at least eight hours per day within a year.
Q: How can stem cells aid brain function recovery?
Dr. C: Simply put, stem cells replace cells lost from brain injury. Stem cells are undifferentiated cells that can change into various types of other cells, from muscle cells to brain cells.
Neural stem cells are self-renewing, multipotent cells that generate neurons (the functional unit of the nervous system) and glia (supportive cells of the nervous system). Various studies have reported the therapeutic effect of stem cells for repairing damaged brain tissue.
Interestingly, as the result of chemical cues released from the site of brain injury, stem cells have been shown to use these signals to migrate to the site of injury, differentiate into the cell types lost from injury, and integrate into the neuronal circuitry to facilitate recovery.
However, this reparative response by stem cells is limited in the nervous system by such factors as the extent of the injury, the presence of molecules at the injury site that inhibit repair, the age of the recipient, etc.
Q: How do brain injuries affect hormones?
Dr. C: Brain injuries can have significant effects on hormone regulation in the body. The hypothalamus and pituitary gland, located in the brain, play key roles in controlling the release of hormones that regulate various bodily functions.
Brain injury, particularly in areas affecting these structures, can lead to dysfunction in the release of cortisol, thyroid hormones, growth hormone, and reproductive hormones (e.g., luteinizing hormone, follicle-stimulating hormone), potentially leading to various physiological, reproductive, and metabolic disturbances.
Q: How can brain injuries be prevented?
Dr. C: This is all about lifestyle changes that help to reduce risk, e.g., wearing a seat belt when driving, wearing a helmet when riding a bike or motorcycle, reducing participation in contact sports, preventing older adult falls, improving safe play in sports, keeping firearms unloaded and locked away.
Q: Why do brain injuries often have legal or financial ramifications?
Dr. C: Overall, the combination of medical expenses, lost income, legal liability, and long-term care needs can result in substantial legal and financial ramifications for individuals and their families affected by brain injuries.
Q: What are some exciting new areas of brain injury research?
Dr. C: The NIH funds researchers studying basic, clinical, and translational traumatic brain injury research.
For example, the University of Pennsylvania School of Medicine was recently awarded an $8 million grant to identify and study TBI biomarkers (a biological molecule found in blood or other bodily fluids or tissue that is a sign of a condition or disease) with the hope of testing new TBI treatments in clinical trials.
Stanford researchers are using artificial intelligence to produce models of mechanical stress on the brain, with the hope that this approach could reveal a better understanding of why concussion sometimes leads to lasting damage, and other times does not.
Early in 2024, a study published in Nature Medicine showed that a single dose of ibogaine (a naturally occurring psychoactive substance) improves symptoms of TBI, post-traumatic stress disorder (PTSD), depression, and anxiety in combat veterans.
Resources
To learn more about brain injury, visit the TBI pages at the NIH and the U.S. Centers for Disease Control and Prevention (CDC). And every March, see what you can do to help raise Brain Injury Awareness. Of course, if you happen to be in Sint Maarten (the home of AUC), you can also stop by Dr. Colello’s office to see if he has a few minutes to spare.
At AUC School of Medicine, we’re training future neurologists (physicians who study the brain) and other specialist physicians. Our 2023–2024 MD graduates achieved a 97% first-time residency attainment rate,* and are now beginning their post-graduate training across 22 specialties. Learn more about AUC and our Doctor of Medicine (MD) program, as well as the requirements for admission. Thank you, Dr. Colello, for the valuable information!
*First time residency attainment rate is the percentage of students attaining a 2024-25 residency position out of all graduates or expected graduates in 2023-24 who were active applicants in the 2024 NRMP match or who attained a residency position outside the NRMP match.