Concussion Symptoms: Causes & How Long They Last
Concussion symptoms can be confusing. They don’t always show up immediately, they can come and go, and they don’t always go away without treatment. We treat concussion patients every day and answer these questions for our patients regularly. That’s why we’ve put together a guide to concussion symptoms, including:
- What symptoms can appear in adults, teenagers, or children and toddlers
- Types of concussion symptoms
- The long-term and short-term effects of a concussion on the brain
- How long common symptoms typically last
- Why symptoms of a concussion might be delayed
- Information on concussion recovery
In case you’re in a hurry, we’ve also put together this signs and symptoms of a concussion checklist:
If you have any of those symptoms, combined with a known head injury, you could have a concussion.
Note: Have your concussion symptoms lingered for weeks, months, or even years? On average, our patients’ symptoms improve by 60% after just one week of treatment at our center specializing in post-concussion therapy. To see if you are eligible for treatment, sign up for a consultation with our team.
Symptoms of a Concussion in Adults
We’ve categorized adult concussion symptoms by when they typically appear. Symptoms in the “Immediate or Early” column are often observed earlier than not. The symptoms in the second column, “Early or Delayed,” may appear early, but are often noticed later in recovery.
|Immediate or Early||Early or Delayed|
If you’re having balance problems, make sure you’re in a safe environment and that you have a loved one with you, if possible, to keep you safe until they resolve.
Memory loss is uncommon outside of brief amnesia associated with the event that caused the concussion. If you experience more than mild short-term memory loss, consult with a medical professional.
Symptoms that are more dangerous (but which still do not necessarily constitute an emergency) are weakness or decreased coordination, repeated vomiting or nausea, and slurred speech. Sometimes, head injuries cause startling, more severe symptoms. If you experience any of the following symptoms, get medical attention immediately.
Go to the Emergency Room if You:
- Are increasingly confused, restless, or agitated
- Can’t recognize certain people or places (disorientation)
- Exhibit strongly unusual behavior (like impulsive or dangerous decision-making, making odd or illogical statements, drunken appearance, etc.)
- Have convulsions or seizures
- Have one pupil that is larger than the other
- Experience excessive drowsiness or do not awaken
- Lose consciousness
These are symptoms of serious brain injury and necessitate immediate medical attention.
Symptoms of a Concussion in Teenagers
The list of concussion symptoms for teenagers is the same as the symptoms in adults listed above. However, parents often ask us how to tell the difference between adolescent angst and concussion symptoms.
Here’s our rule of thumb: If the behavior or complaints you observe in your teen are at all unusual for them, assume it’s the concussion. While some symptoms like irritability, depression, or anxiety may come from other sources, it’s entirely possible that they are from a previous concussion. Trust your instincts and when in doubt, pursue treatment options for a concussion.
It may be that they won’t feel better until they receive adequate medical care.
Symptoms of a Concussion in Children and Toddlers
Many everyday activities put young children at risk for concussions. Try as you might, it’s not possible to prevent every situation that could result in head trauma. But it’s harder to know if they have a concussion since toddlers can’t always tell you exactly what’s wrong. They’re still learning how to understand and express what they feel.
If you witness your child fall and hit their head or otherwise take a blow to the head, keep an eye out for symptoms and consider seeking medical advice. Nearly 50% of all traumatic brain injuries in children come from falls. You can find more health information at the CDC (Centers for Disease Control and Prevention) Heads Up website.
Clues to Symptoms
Children may behave in ways that help you know if they’re experiencing a concussion. Signs of pediatric concussion include these behaviors:
- Angered easily
- Appear dazed
- Cry more than usual
- Change their behavioral patterns around food
- Exhibit new sleep patterns and behaviors
- Lose their balance more frequently or seem unsteady
- Seem unusually tired
- Seem uninterested in favorite toys or activities
- Touch their head a lot to indicate it hurts
Further reading: How to recognize post-concussion syndrome in children
Go to the Emergency Department if:You know they bumped their head or experienced shaking or jolting, and...
- They have any of the emergency room-worthy symptoms listed for adults
- They just won’t stop crying
- They refuse nourishment
Ultimately, if there’s any question as to whether your child is suffering from a concussion, it’s always better to have your child’s doctor check them over than to assume nothing is wrong.
Types of Concussion Symptoms
Sometimes, patients are given a concussion grade based on the severity of the circumstances around their concussion. But often, these grades fail to predict the severity of symptoms or how long they last.
This study from January 2020 published in Neurosurgery offers a different way to think about concussion symptoms. People who have a concussion will often experience symptoms from more than one grouping:
- Vestibular symptoms (symptoms related to balance, like dizziness, trouble balancing, and nausea)
- Ocular-motor symptoms (symptoms related to vision and movement, like blurry vision and difficulty reading)
- Headache (learn more about post-traumatic headaches)
- Cognitive symptoms (symptoms that relate to how you make decisions and process information, like brain fog, memory problems, difficulty concentrating, and trouble with word retrieval)
- Mood-related symptoms (symptoms that affect how you feel, such as anxiety, depression, irritation, and feelings of overwhelm)
Knowing which types of symptoms you’re experiencing can help guide your treatment plan.
Effects of a Concussion on the Brain
A concussion is a mild traumatic brain injury (mTBI). You don’t have to receive a blow to the head to get a concussion: a concussion may occur whenever you receive a “bump, blow, or jolt to the head or by a hit to the body that causes the head and brain to move rapidly back and forth. This sudden movement can cause the brain to bounce around or twist in the skull, creating chemical changes in the brain and sometimes stretching and damaging brain cells.” (Centers for Disease Control and Prevention or CDC)
If your car stops suddenly, for example, there’s a chance your brain could be jarred enough to hit your skull and/or cause whiplash (even if you’re wearing a seat belt). That jostling is enough to cause symptoms.
Short-Term Effects of a Concussion on the Brain
In severe traumatic brain injuries, you might incur physical damage to the skull and brain. But a concussion, by definition, means you have not suffered severe physical damage. If you have a concussion, you suffer from the effects of a mild TBI: temporary damage to brain cells (popularly called “bruising”) and inflammation.
Inflammation is the body’s natural response to an injury. Blood and other fluids rush to the site of the injury so that the body can effect repairs. Brain swelling can result from this process.
During normal brain function, your brain calls for increased blood flow to deliver oxygen when and where it’s needed (a relationship known as neurovascular coupling, or NVC). For example, if you’re reading a book, then the parts of your brain governing sight and reading comprehension would call for increased blood flow. That gives your brain the energy it needs to help you perform those tasks.
If inflammation and cell damage from the concussion interfere with the signaling between cells and blood vessels, you might struggle with certain tasks. For example, if a brain region governing attention can’t get the right amount of nutrients at the right time, you might struggle to follow a conversation or find yourself unable to focus for more than a few minutes at a time. If other brain regions try to help, they have to work harder to complete the same task.
In other words, communication between neurons along the original pathways is disrupted because they don’t get enough oxygen (among other things). As a result, you may experience any number of concussion symptoms.
In an ideal recovery, the brain will resume using the most efficient pathways to deliver oxygen and information. But that doesn’t always happen.
Long-Term Effects of a Concussion on the Brain
Sometimes, the brain doesn’t return to using the most efficient pathways. Instead, it may continue using the less efficient pathways formed during rest and recovery. In most cases, the number of pathways affected is not enough for you to notice a difference in your day-to-day life. If it is, you might experience persistent post-concussion symptoms (also known as post-concussion syndrome, or PCS).
Some people develop PCS after just one concussion. Others develop it after a second concussion — or even multiple concussions. That’s because the more concussions you have, the more opportunities your brain has to solidify suboptimal (less good) ways of sending information and getting oxygen. Those changes can be responsible for everything from headaches to mood changes to forgetfulness.
Think about suboptimal signaling pathways in your brain like the different routes you can take to commute home from work. Some roads have more traffic than others. If you have to route around an accident, you’ll take longer to get home. And if you get stuck in traffic, who knows how long it will take. In those situations, you end up tired and frustrated because what should be an easy trip home, isn’t.
During healthy brain function, communication “traffic” would be equally distributed along existing roads. Suboptimal pathways are like getting stuck in a traffic jam or having to take the long way around. Those cells are unable to call for enough oxygen to do their jobs, so other cells have to do it. The more that happens, the more tired your brain becomes and the more opportunity there is for your symptoms to emerge.
Once those suboptimal pathways are set in place, it can be difficult to retrain them without expert assistance. Rest is not adequate health care to fix lingering brain dysfunction from a mild traumatic brain injury. But with a combination of physical therapy, cognitive therapy, diet, and calming activities like meditation, those pathways can be significantly improved.
Other Causes of Long-Term Symptoms
Certain post-concussion complications can result in long-term symptoms. Here’s some reading if you’d like to learn more:
- Autonomic nervous system dysregulation (dysautonomia) after a head injury
- Vestibular dysfunction after concussion
- Post-trauma vision syndrome
- Hormone dysfunction after head injury
- Risks & complications women face with concussions
When Do Symptoms of a Concussion Appear?
When it comes to symptoms, everyone is different. Most people have symptoms immediately. Those symptoms might go away and come back, or new symptoms could appear a few days later. Below are the answers to a few commonly asked questions about when concussion symptoms appear and disappear.
How Long Should the Symptoms of Concussion Last?
How long symptoms stick around depends on the severity of the concussion. It can also vary from person to person. Mental confusion at the time of the injury is the best predictor of long-lasting symptoms (meaning, if you experience confusion when injured, you’re more likely to have symptoms that don’t go away quickly).
In general, symptoms of a concussion should resolve in two weeks. Some people have symptoms for longer — up to three months. Concussive symptoms typically resolve in 7 to 10 days (sports-related concussions) or within 3 months (non-athletes) (Epps and Allen, 2017). If symptoms don't resolve after three months, they probably won’t go away without therapy.
The above guidelines hold true for roughly 80% of the population (although this number fluctuates in any given study). The remaining 20% take longer to recover than most people — or might not see their symptoms go away at all.
In this article published in JAMA Neurology, the authors state that many concussive patients experience the evolution of symptoms five years after mTBI, not the resolution of symptoms. 72% of patients had worsening global disability after five years. This clearly evidences that chronic concussion symptoms are likely to progress over time.
Recovery time isn’t correlated with the injury source. Someone who has a concussion from a car accident, for example, is likely to need the same recovery time as someone with a concussion in sports such as football or snowboarding.
In general, if your symptoms haven’t gone away after two weeks, it’s time to look for treatment alternatives. And if it’s been three months, you need to find a provider specializing in post-concussion syndrome treatment. (If that sounds like you, we offer a consultation to patients who would like to determine their eligibility for post-concussion treatment.)
Can Symptoms of a Concussion Come and Go?
Yes, symptoms of a concussion can come and go. Some patients feel great after their initial recovery. Then a few days or weeks later, those symptoms return with ferocity. Why?
It may be that your brain is still using suboptimal pathways to relay information and oxygen. When your symptoms are gone, that means your brain is still doing a pretty good job of compensating. But when symptoms return weeks, months, or even years later, it’s often because some other stressor — an illness, emotional trauma, extra stress at work — is too difficult for the brain to handle.
Can Symptoms of a Concussion Be Delayed?
Yes, symptoms of a concussion can be delayed (although it’s fairly rare). Some patients don’t feel any negative effects from their concussion. Or, they might have a few symptoms that resolve (like headaches), followed by new symptoms (like overwhelm or anger).
Remember those suboptimal pathways? The changes might not be severe enough for you to notice… at first. But sometimes it’s the start of a downward spiral. In these cases, when a certain section of the brain doesn’t receive enough oxygen, its ability to signal for more oxygen is negatively impacted. Over time, the reduced oxygen and signaling make each other worse.
Eventually, that negative loop increases enough for you to notice the symptoms. For example, you might have had no problems with vision immediately after your concussion. But a few months later, you might discover that your peripheral vision is disappearing. That negative cycle of oxygen insufficiency and reduced signaling is why.
Concussion Recovery: Which Doctors to See and When
If you experience trauma to the brain, watch out for the emergency symptoms listed above. If any of those symptoms emerge, visit a hospital immediately. They might have you undergo an MRI or a CT scan to make sure there is no other damage to your brain. (Unfortunately, MRI and CT scans cannot prove the existence of a concussion, but they can rule out other injuries such as a skull fracture or brain bleed.)
If you’re showing signs of concussion, it’s a good idea to see a healthcare professional soon after the injury. As long as you’re not showing any signs of an emergency, it’s your choice whether to go the same day or to book an appointment for the next day or two.
When you do seek a healthcare provider, look for a head injury doctor such as a physical medicine & rehabilitation (PM&R) physician, a sports medicine practitioner experienced with concussion treatment, or someone at a good concussion clinic. If you’re in the Salt Lake City, Utah area, we recommend Neural Effects for acute concussion treatment.
While many concussions fully resolve on their own, some don’t. And either way, you can speed up your recovery time by following a good recovery plan.
If you decide not to visit a physician, follow a strict 48-hour rest period. Avoid all over-the-counter pain medicines except Tylenol (acetaminophen) during this time. This is because NSAIDs (such as Ibuprofen, Aleve, and Advil) could exacerbate bleeding in the brain.
Afterward, you can gradually increase cognitive and physical activity (make sure to do exercise that is safe after a concussion). If you play contact sports, don’t resume practice until you’re fully healed. Athletes are especially at risk of second impact syndrome (SIS), a life-threatening condition that can develop when they sustain another concussion before the first one is healed. That said, developing SIS is not limited to concussion in sports — avoid any activity that could result in a concussion. Give yourself two weeks for symptoms to resolve; if they don’t, we highly recommend visiting a concussion treatment provider.
If the signs of a concussion are still present after two weeks, it’s time to get a professional involved. Post-concussion syndrome, in most cases, will not fully resolve on its own. Targeted physical and cognitive therapy can make a huge difference in outcomes. Read more here about therapy options for ongoing concussion symptoms or visit these posts about specific therapy types:
- Vestibular therapy for concussion and PCS
- Physical therapy for concussion and PCS
- Cognitive therapy for concussion and PCS
- Speech therapy for concussion and PCS
Note: Have your concussion symptoms lingered for weeks, months, or even years? Our patients’ symptoms improve by 60% on average after treatment at our center specializing in post-concussion therapy. To see if you are eligible for treatment, schedule a consultation with our team.
About Dr. Mark Allen PhD
Mark D. Allen earned a PhD in Cognitive Science at Johns Hopkins University with post-doctoral training in Cognitive Neuroscience and Functional Neuroimaging at the University of Washington. He has 15 years of research and clinical experience in fMRI, with 22 publications in tier-1 peer-reviewed scientific journals, 3 book chapters, and dozens of presentations at scientific and professional conferences in neuroscience, neuroimaging, and neuropsychology. Having collected and analyzed fMRI data from over 1,000 experimental subjects and over 300 clinically-referred patients, Dr. Allen is a pioneer and expert in the development of fMRI for use in clinical settings.