*About (See that’s the concussion doing it’s thing)

For this blog, I will again include potential symptoms as well as neuroscientific aspects behind concussions. However, I first want to focus on some other information provided to me by a friend currently dealing with a concussion. Hopefully this will prove to be equally, if not more, beneficial to you. Wishing her a steady recovery, here are 10 things my friend wishes people knew about concussions:

1. Every concussion is different. One experience (maybe your own or one that you’ve heard about) is not necessarily generalizable to others’ experiences. It’s really hard to understand what it’s like until you’ve had one.
2. It may be a moot point, but you can’t see concussions. Therefore, even if someone seems fine, it doesn’t necessarily mean that they are. 
3. Concussions make everything harder, especially because they never really “turn off” and your head constantly either hurts, has pressure, or feels foggy. While it varies from person to person, concussions can make reading, seeing, writing, listening, thinking, sleeping and, therefore, just existing hard. It makes you feel helpless.
4. Have compassion, be patient, give endless amounts of love. Having a concussion can make people feel isolated and alone because they have to spend a lot of time in quiet environments, which can often mean by themselves. For people in your life who struggle with mental health, all of that forced alone time can especially take a toll. 
5. Be there for your loved ones with concussions, but try to avoid frequently asking “How’s your head?” or “How are you feeling?”. Of course, it’s important to show that you care and to let them know that they can talk to you about their struggles any time. But on the other hand, they are constantly dealing with their concussion and probably would appreciate a different topic of conversation once in a while! 
6. Instead of making people feel guilty, be conscious of people’s concussions because they have no control over the symptoms. Trust that they are fighting and handling life as best they can, even though you may not see it. They are probably already pushing their brain to do more than it should. It’s not their fault that they are not able/ supposed to do certain things (like use technology, watch movies, or be in a loud environment). 
7. Concussions are not about “just working hard” and “pushing through”. Pushing through is painful, not productive and not helpful in the recovery process. 
8. Symptoms can rapidly and unexpectedly change. Someone may be feeling alright one minute, but not so much the next. This can be applied to the recovery process as well because it is often not linear. 
9. Never make the person with the concussion feel like they need to “prove” their injury to you. Believe them. Especially when it has already been diagnosed.
10. Support them. Love them. Hugs galore (if they like hugs).

After providing this advice based on personal experience, the information below covers some of the medical and scientific aspects of concussions. 

Types, Causes & Symptoms

Causes of concussions are usually significant blows to the head or upper body, sudden acceleration or deceleration of the head, or blast injuries. These also mark the different types of concussions the brain can experience, depending on the nature of the event. Getting any one type of concussion can occur in a wide variety of circumstances.

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Risks

One of the circumstances in which concussions are most well known to occur is football. Lots of research has been conducted for this sport specifically (especially surrounding CTE), but contact sports in general (such as hockey, rugby, soccer, boxing, etc.) pose increased risks for getting a concussion. Furthermore, they are commonly diagnosed in the military as well from events as simple as falling to something as serious as bomb blasts.

Of course the general population can suffer from concussions due to falling as well, but also due to many other incidents like motor vehicle collisions, pedestrian or bicycle accidents, or physical abuse. Having had a concussion before also makes it easier to sustain a second concussion, while possibly making the symptoms more severe as well.

Symptoms

The symptoms and potential consequences of concussions are numerous and may include seizures, loss of consciousness, memory loss, nausea/ vomiting, headaches, mood changes (irritability, anxiety, depression), sensitive vision and hearing, difficulties with physical coordination, memory and concentration issues, lethargic or easily fatigued, trouble sleeping and waking up.

Science of Concussions

There are many different findings within concussion research as to what the biological/ neural expression of a concussion could look like. One such finding is that mechanoporation (small pores or defects in the membrane) can lead to potassium efflux out of and sodium & calcium influx into the neuron, as well as hyperacute indiscriminate glutamate release. This increased firing of neural cells can then lead to a “depression-like” state, where the firing is less likely, which could be the reason for some of the postconcussive impairments. 

After this increased firing, ionic pumps are actively trying to restore ionic homeostasis of the cell. However, these pumps require energy in the form of ATP (adenosine triphosphate), which means that cellular storage is often strained or even depleted and hyperglycolysis occurs (increased glucose utilization two standard deviations above normal) in order to restore ATP levels. 

Other pathologies can include cytoskeletal damage, which means that the structural integrity of neurons is lost and in severe cases can lead to axonal disconnection, leading to difficulties in axonal transport. Neurotransmission is also altered due to changes in the composition and function of glutamatergic NMDA receptor subunits. Under some circumstances inflammation and cell death can occur as well. For more information on the science click here.

Do you ever crave food to the point where you are pretty sure you are addicted? Well, turns out you might actually be addicted to food. Recent studies have connected obesity and overeating to changes that manifest in the brain, specifically linked to energy homeostasis which is the balance of energy in your body. The hypothalamus in your brain is what maintains this homeostasis by regulating feeding behavior and energy expenditure, in other words when you eat and when you exercise is controlled by the hypothalamus. You may be questioning how your brain knows what the rest of your body needs, well this is through insulin and leptin signaling. Insulin and leptin begin signal cascades that lead to the response “stop eating and expend energy.”

Leptin is a hormone produced by adipocytes, fat cells, and binds to receptors in the hypothalamus. The receptor then begins a signal cascade that activates the synthesis of the neuropeptides proopiomelanocortin (POMC) and cocaine and amphetamine regulated transcription (CART). These neuropeptides then lead to the “stop eating and expend energy” response. The leptin signal cascade also results in the inhibition of agouti-related peptide (AgRP) and neuropeptide Y (NPY) which are neuropeptides that signal the “eat now” response. This is great, because it tells your body you’re full. You have enough energy to do life. But there’s a catch! FOXO1 inhibits the action of this signaling cascade leading to the opposite response, “eat more.” To combat this, insulin steps in.

Insulin is a hormone produced in the pancreas, that also binds to receptors in the hypothalamus. Insulin initiates a signal cascade that kicks FOXO1 out of the nucleus so it can’t disrupt the leptin signaling. The figure below shows how leptin and insulin control appetite in the hypothalamus.

If there is a lack of leptin or insulin, POMC and CART will not be synthesized to give the “stop eating and expend energy” response. The figure also shows that ghrelin, produced in the stomach will also induce appetite. AgRP and NPY will be synthesized leading to the “eat now” response. If you haven’t eaten for a while and need some energy this is good. But, if this signal occurs even when you’re not hungry, then you have a problem. This uncoupling of the “eat now” response and the amount of energy one has is key in obesity.

So, how does this signal happen when you don’t need energy? Obesity leads to this disruption of energy signaling in a number of ways. One way is that a high fat diet causes the activation of inflammation in the hypothalamus which elicits a stress response from the endoplasmic reticulum (ER). ER stress leads to leptin and insulin resistance, therefore increasing AgRP and NPY neuropeptides and the “eat now” response. The body still produces leptin and insulin, but now the hypothalamus can’t send out the correct signal. This leads to overeating because an individual will continue to eat after attaining their energy threshold. In mice, the hypothalamus returned to its normal size after three days on a low-fat diet. So, no worries, one meal won’t send you down an uncontrollable food tunnel. However, prolonged high fat diets could lead to the uncoupling of energy need and feeding behavior. Therefore, proper nutrition and portions is key to maintaining a healthy lifestyle.

In America, it seems that athletics is just as stressed, if not more than, as academics. We live in a culture where professional athletes are praised and put in the spotlight, and the pressure put on them to perform no matter the circumstances is extremely high. So, despite dangerous injuries, professional athletes would often stay in the game to prove their “toughness,” and that tended to be the expectation from coaches since the inception of athletic events. Unfortunately, high school athletes who would follow professional athletes would take cue from them and buy into the idea that they should play at all costs. For specific injuries like concussions, which we now know are extremely dangerous and serious, one important question to ask is why do many high school athletes not report the symptoms of concussion?

Just a Few Reasons

1. Winning at all costs

High school athletics are important and are most often extremely beneficial to kids with regards to social connections, teaching discipline, and learning vital teamwork skills. However, far too often are high school athletics not kept in perspective.

When asked in a study that was published by the Journal of Athletic Training, up to 55% of high school athletes reported that they didn’t or wouldn’t report a concussion. A strong argument could be made that one contributing factor is the athletes did not want to sacrifice playing time to protect their physical health. They are taken too seriously, specifically when it comes to athletes’ injuries.

    2. “I can’t let my team or coach down”

Although a noble motivation, putting the team or opinion of the coach ahead of one’s physical health is extremely risky. Many athletes feel myriad emotions when it comes to physical injuries, and a common one is that they believe they will look “weak” if they complain of pain. According to an article by Reuters Health, males especially tend to be more sensitive to how their fellow teammates and coaches view them. This is arguably due to the expectation that men are supposed to be strong and resilient, and showing emotion is can be considered a “vulnerability” in the sports realm.

   3. Honest Ignorance

At higher levels of athletics like college and professional sports, the signs and symptoms of concussions are well known and monitored at the slightest instance of a hit to the head.

However, in high school athletics, strict regulations like that of college and professional sports are not uniformly enforced. This leads to high numbers of ill-informed or uninformed high school athletes and coaching staffs. Not knowing the symptoms of a concussion is dangerous, and too many kids have stated that they did not know they had a concussion while they were concussed.

The Solutions

One solution to these problems first and foremost is education. Coaches need to understand the seriousness of concussions and the lasting effects they can have, like difficulty concentrating, personality changes, difficulty with memory, and many more. These are exacerbated if and when someone sustains a second concussion, which is easier to obtain having had an initial concussion. Another point of importance to be stressed to high school athletes, parents of athletes, and coaching staffs is: keep athletics in perspective. Sacrificing enduring brain health problems for a game is never the answer. Brain injuries are unlike injuries to other parts of the body, and injuries to the brain must be treated accordingly. Not to diminish the importance and amazing accomplishments to be had in high school athletics, but after all, it is just a game.

The Science

Many things have been studied that occur after a significant impact to the head is sustained. After impact, potassium flows out of the cell while sodium and calcium flows into the cell, and this is allowed because of defects in lipid membranes that occur after the trauma. This causes an ion flux and a subsequent depolarization that can lead to depression-like responses that are attributed to the post-concussive impairments. To combat this, ionic pumps that require ATP are overactive, which leads to hyperglycolysis. This results in an imbalanced energy supply and demand, which ultimately leads to a variety of metabolic changes that are serious to say the least. The force of an impact can also damage the cytoskeletal structures like dendritic arbors, axons, and astrocytic processes. This often leads to the loss of integrity of axons, and in extreme cases axonal disconnection occurs. Overall, it is not just one specific thing that can be pinpointed when determining the cause for a concussion but rather many things that can and do contribute to the effects of a concussion.

CONCUSSIONS are one of the most commonly encountered sports injuries where rates are estimated at two million sport related concussions per year in the United States according to the Brain Injury Research Institute. This number is potentially much larger due to the lack of knowledge and awareness about concussion and brain injuries. There has been an increase in research attempting to understand what happens in the concussed brain, but there is a long way to go to help identify treatment plans and return to play protocols. For now, we maybe shouldn’t listen to Zac Efron and his High School Musical buddies. So let’s keep our head out of the game and, instead, focus on raising awareness about concussions and other injuries to the brain.

A vast array of symptoms that can be associated with concussions and traumatic brain injuries (TBI) are a result of the diversity and broadness of factors relating to basic neurobiology and a neurometabolic cascade. These factors include ionic flux and glutamate release, energy crisis, cytoskeletal damage, axonal dysfunction and altered neurotransmission, and inflammation.

IONIC FLUX AND GLUTAMATE RELEASE

Upon a biomechanical injury, potassium efflux and sodium and calcium influx occur due to a damaged phospholipid membrane. An efficient action potential will not be able to be produced because of abnormal depolarization from the rapid influx of sodium and calcium.

ENERGY CRISIS

In an effort to maintain cellular homeostasis regarding ionic flux, ionic pumps that require ATP are shifted into overdrive. This leads to a depletion of energy reserves, thus resulting in reduced cerebral blood flow and an imbalance between energy supply and demand. Prolonged calcium influx leads to increased intracellular calcium and greater amounts of calcium to be sequestered in the mitochondria. Too much sequestration can result in mitochondrial dysfunction which causes the energy crisis.

CYTOSKELETAL DAMAGE

The cytoskeletal structure which include microtubules and microfilaments consist of delicate and complex components. When damage is implemented to a brain region, neurofilaments can easily be phosphorylated and break. Axonal influx of calcium results in the breakdown of proteins into smaller polypeptides on cytoskeletal components. This damage makes the neurons more prone to axonal disconnection and death. After a TBI, ongoing cerebral and hippocampal atrophy may be present. The progressive atrophy can show the appearance of cognitive deficits later in life. The occurrence of a TBI before full recovery from a previous TBI may more likely trigger activation of intracellular proteases and the cascade that leads to apoptotic cell death.

AXONAL DYSFUNCTION AND ALTERED NEUROTRANSMISSION

Increased axonal permeability after a TBI is a result of the vulnerability of the axon. Consequently, this can lead to overall axonal dysfunction. A damaged neuron where neurofilaments and microtubules are altered allows for the neuron to not normally function. Injury to the axon and other white matter areas occurs along with mechanoporation, stretching of individual axons, disruption of axonal transport, axonal misshaping, and axonal disconnection.

Altered neuronal transmission is present after a TBI and occurs due to an imbalance in excitatory and inhibitory neurotransmission. This imbalance is seen due to alterations in the glutamate receptors or GABA receptors which alter excitation and inhibition. Alterations in glutamate, an excitatory neurotransmitter, affect the normal functions of calcium flux and the activation of downstream signal transduction molecules. Decreased levels of GABA, an inhibitory neurotransmitter, affect fear-based learning associated in the amygdala.

INFLAMMATION

Changes in inflammatory markers following a TBI has shown an activation of microglia in the cortex. Microglia function as macrophages in the central nervous system to mediate immune responses. Upon damage to the brain, inflammatory changes are triggered by the upregulation of cytokine and inflammatory genes. Inflammation, although an evolutionary mechanism for protection, has also been shown to induce damage to brain regions that relate to long term side effects. For example, microglial response to damage in the substantia nigra has been shown to increase risk of Parkinson’s Disease after a TBI.

WHY IS THIS SO IMPORTANT?

The research presented above sheds light onto why there are so many symptoms involved with brain injury and concussion. A list of symptoms is listed below:

• Migraine headache
• Photophobia and phonophobia
• Vulnerability to second injury
• Impaired cognition
• Slowed processing and slowed reaction time
• Chronic atrophy
• Development of persistent impairments

Concussions affect each individual differently and symptoms depend on a number of factors including strength of trauma and the brain area affected by the trauma. When an individual is experiencing these symptoms, they must be monitored closely. Both physical and mental rest can speed the recovery of concussions. Unfortunately, there is still much more research to better understand how to prevent concussions and the symptoms associated with them.

CONCUSSIONS and any injury to the brain are not to be taken lightly. The broadness of symptoms associated can have long term affects. Management of concussions will continue to evolve as more research develops. This will allow us to better understand the steps toward prevention, treatment, and return to play protocols. Protection of athletes and all those more prone to concussion is the number one priority. If you are experiencing any of the concussion symptoms talk to a health professional and play it safe by getting your head out of the game!

For more information on the research presented, follow:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4479139/

For more information on the symptoms associated with concussion, follow:

https://www.mayoclinic.org/diseases-conditions/concussion/symptoms-causes/syc-20355594