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Concussion: The invisible injury

What goes on in the head of a concussed person is more than meets the MRI

Artistic rendering of geometric shapes inside a woman's head

The more I worked with patients post-concussion, the more I saw how frustrating and isolating their condition was for them. I would commonly hear "my family/friends/work don't understand" or "just because I look fine, doesn't mean I feel fine." And this is because, in more ways than one, concussion is an invisible injury. Medically, a concussion is not visible with our current imaging technology, including MRIs and CT scans. If you go to the emergency room after a concussion, you may hear "You're imaging is negative. You're fine. You can go home." But you may feel nothing close to fine. Socially, people are aware that you were in a motor vehicle accident or fell off your bike or hit a player's head in soccer, but nothing is broken and all your bruises have healed. They don't understand why you keep forgetting things, or why you're so tired all the time, or why you jump at the slightest sound. So what is going on inside your head that makes it so hard for others to see?

“Just because I look fine, doesn't mean I feel fine. ”

Concussion Myths

Before we dive into the nitty gritty pathophysiology of concussion, let's clear up a few myths.

You have to hit your head to get a concussion.

FALSE. Concussions can most definitely be caused by hitting your head, but you can also sustain a concussion with a fast acceleration-deceleration force as in a car accident or whiplash. In addition, you can get a concussion from being too close to a blast from an explosive device. The exact mechanism of blast injuries is still being determined, but it is thought that the shock wave from the blast transmits through the skull causing a rapid pressure increase inside and a subsequent concussion.

You have to lose consciousness to experience a severe concussion.

FALSE. Loss of consciousness has not been associated with the severity of persisting concussive symptoms.

Concussion is a form of brain damage.

TRUE and FALSE. A concussion is a mild traumatic brain injury (mTBI). There is no structural damage to your brain, which is why it isn't visible on imaging. However, a concussion does cause physiological changes in the brain. Metaphorically speaking, a concussion is a software issue, not a hardware issue.

You need to lay in a dark, quiet room for days immediately after a concussion.

FALSE. The most recent International Consensus Statement on Concussion in Sport reports that no more than 24-48 hours of relative rest is beneficial following a concussion. The term relative is to indicate that if you are an active person, you should not confine yourself to bed for days, but rather avoid your regular exercise routine and any cognitive (work/school) demands. If you are a very inactive person, then laying in bed may be the type of relative rest you require. Always consult with a healthcare provider who is knowledgable in concussion to determine how much rest is appropriate for you.

There is no treatment for concussion.

FALSE. Most people will recover from a concussion within 2 weeks. If you are experiencing symptoms beyond 2-3 weeks, there are specific treatment options to target your specific symptoms. Read on to learn more about what those are.

What is a concussion?

When you experience a concussion, you go through a few stages. If you want to nerd out, feel free to read the details of each stage. Or, just jump straight to the BOTTOM LINE.

Initial impact

As you now know, this could be a direct force to the head, a rapid deceleration, or from a blast injury. At this point, the neurons in your brain stretch from the force or pressure, causing channels along the neurons to open and let certain ions in (sodium) and other ions out (potassium). This flux in ions causes these neurons to be exited, or activate, and leads to the activation of all other neurons they are connected to (this is A LOT of neurons).

BOTTOM LINE: A ton of neurons in your brain "excite", or activate, all at once. This is sometimes referred to as an "excitatory storm."

Drawing of two neurons

Energy Crisis

After this "excitatory storm", your brain tries to restore homeostasis or its "normal" state by pumping these ions (sodium and potassium) back where they need to be. This pumping mechanism requires energy, or ATP. Your brain is using up so much ATP, that it experiences an energy deficit. This can last up to a week after the event and is why some people after a concussion feel fatigued and unable to resume their normal levels of activity.

BOTTOM LINE: Your brain uses a lot of energy to try and calm the excitatory storm. This places your brain in an energy crisis.

Symptom Resolution OR Persisting symptoms

Most people spontaneously recover from a concussion. For adults, 85-95% recover within 2 weeks (some research suggests 3 months). For children, 70-80% recover within 3 months. However, there is a significant group of people that do not recover in these time frames and can have symptoms persisting for months or even years if not properly addressed. So why do some people's symptoms persist? Great question! Read on.

BOTTOM LINE: Most people recover from a concussion within a couple of weeks, and if you don't, there's treatment!

Infograph showing recovering timeline (x-axis) and energy (y-axis) in the first few months to a year after a concussion

Persisting Post-Concussion Symptoms (PPCS)

This used to be called Post Concussion Syndrome (PCS); however, newer terminology is being encouraged as it more accurately reflects what people experience. We are moving away from the term "syndrome" because this suggest there is a consistent group of symptoms people experience. This couldn't be further from the truth. I'm always telling my students, "you've seen one concussion, you've seen one concussion," because these symptoms are unique to the individual and how they impact their life. So, because there are a variety of symptoms that may persist after a concussion, there are a variety of underlying reasons for those symptoms, including:


Our autonomic nervous system is responsible for all "automatic", or unconscious, bodily functions, including our heart rate, breathing, and digestion. This system can be imbalanced after a concussion causing symptoms with exertion or exercise including fatigue, dizziness, headache, digestion issues, and abnormal fluctuations in blood pressure or heart rate. At Whidbey Dizziness & Balance, I assess for autonomic sources of your symptoms with an exercise stress test and work with you to develop an individualized, progressive exercise program. This type of treatment is supported by some of the strongest evidence in concussion literature to date.


After a concussion, many people will report symptoms of dizziness and imbalance, blurred or double vision, difficulty reading or using a computer, or symptoms in visually busy environments (like riding in a car or going to a grocery store). These symptoms can arise from the visual system and/or the vestibular system. Some of my patients will say they went to their eye doctor after their concussion and everything looked fine. While their eye organ may be healthy, the way the brain is processing visual input is not operating efficiently and is causing their symptoms. This requires specialized knowledge to asses and treat, usually by a Neuro Optometrist. I am trained in screening for such deficits and recognizing when you may need this specialized help.

Some of these symptoms arise from the vestibular system. This system lies in our inner ear and tells our brain where we are in space and in which direction we are moving. A concussion can cause dysfunction in this system producing symptoms of dizziness, nausea, motion sensitivity, and imbalance. These symptoms can effectively be treated by a trained vestibular therapist, such as myself, and is my primary specialty and passion.


Oftentimes, you experience whiplash at the time of your concussion, as in the case of a car accident or any sudden impact. Whiplash can affect the joints, nerves, and blood flow to the neck (cervical spine). Symptoms may include neck pain and stiffness, dizziness, and headache. Cervical symptoms can be treated by a variety of professionals including physical therapists, massage/manual therapists, and chiropractors. At Whidbey Dizziness & Balance, I will perform a comprehensive assessment of your neck and determine if it is the source of your symptoms and identify the most appropriate treatment.


A significant amount of research shows that anxiety, depression, and post-traumatic stress can perpetuate persisting concussive symptoms. I have seen this to be true in some of my patients as well. This is not to say that your symptoms are in your head (although, technically-speaking, they are), but that worrying about or constantly thinking about your symptoms can actually make your symptoms worse and more challenging to resolve. Sometimes, simple techniques in relaxation, breathing, and stress reduction can alleviate a lot of these symptoms. However, in more severe cases, I recommend my patients work with a Licensed Mental Health Counselor or Psychologist.

Metabolic, Inflammatory, Hormonal

A concussion produces an inflammatory response in the brain. This inflammatory response can feed back and forth between your brain and your gut via the Gut-Brain Axis. This can affect your metabolism and also be the source of gut issues after a concussion. For this reason, many healthcare professionals experienced in concussion will recommend an anti-inflammatory diet. While, I provide my patients with generalized nutritional information about what foods are healthy for the brain and which are inflammatory, I always recommend you work with a Registered Dietician before making any significant dietary changes.

A concussion can also affect the function of our pituitary gland, our hormone regulator. In particular, people who have had a concussion may have Growth Hormone and Testosterone deficiencies. This hormonal imbalance can lead to a variety of symptoms. Talk to your primary healthcare provider for more information on assessment and treatment of hormonal causes of persisting symptoms.

Remember, concussion is treatable!

I've had so many patient says, "but I was told there's nothing I can do about it." Remember? Myth! A concussion is a form of trauma to the body. Our body reflexively (or automatically) responds to that trauma in order to protect us. However, sometimes these protective responses persist and we can experience concussion symptoms months or even years after the event. Common symptoms include light/noise sensitivity, dizziness, unsteadiness, and fatigue. At Whidbey Dizziness & Balance, these symptoms can be addressed by balancing the body's protective responses (fight, flight, freeze) with its productive responses (rest and digest) through gentle hands-on therapy to re-integrate these protective reflexes, tailored therapeutic exercises to re-educate your nervous system to process sensory input appropriately, and progressive return to play, learn, and work protocols.

If you have experienced a concussion and are still struggling with symptoms, book an evaluation with Dr. Brooke Lindsley. Or, if you are an athlete and have not received comprehensive baseline testing for this year, book a Baseline Assessment.


  1. Quatman-Yates CC, Hunter-Giordano A, Shimamura KK, et al. Physical Therapy Evaluation and Management after Concussion/Mild Traumatic Brain Injury. J Orthop Sports Phys Ther. 2020;50(4):CPG1-CPG73.

  2. Leddy, John J. Prescribing Aerobic Exercise Post-Concussion. Lecture presented at: 2020 Virtual Concussion Health Summit; September 21, 2020; virtual.


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