Concussion: Symptoms, Recovery, and Treatment

What exactly is a concussion?

A concussion is a mild traumatic brain injury (mTBI) that affects brain function without causing visible structural damage. It occurs when an external force causes the brain to rapidly accelerate inside the skull. It's like when you brake suddenly in a car: anything not secured continues to move.

The term mild traumatic brain injury (mTBI) is also used to describe this injury. In the sports world, the term concussion is more commonly used. Both terms describe the same reality: a temporary disruption of brain function.

The brain floats in a protective fluid inside the skull. During an impact or sudden acceleration, the brain hits the walls of the skull. This movement stretches and twists neurons, the cells that transmit information. The result? Chemical and metabolic changes that temporarily disrupt their function.

A functional injury, not structural

A concussion is a functional injury. This means your brain isn't working as well, but it isn't physically damaged. It's like a computer infected by a virus: all the components are intact, but the system runs slowly.

That's why imaging tests like CT scans or MRIs appear normal after a concussion. These tests show the brain's structure, not its function. The absence of visible abnormalities does not mean you don't have a concussion.

What are the causes and mechanisms of concussion?

Concussion occurs when the brain undergoes rapid acceleration inside the skull. The most common causes include contact sports, falls, road accidents, and direct impacts to the head. The injury mechanism involves a coup-contrecoup or rotational force.

Most common causes

In sports:

• Ice hockey (checking)
• Football (tackled)
• Soccer (heading, collision)
• Cycling (fall)
• Downhill skiing and snowboarding

In daily life:

• Falls (stairs, ladder, ice)
• Car or motorcycle accidents
• Direct blows to the head
• Workplace accidents

Important Fact: A direct blow to the head is not always necessary. A sudden acceleration of the body can be enough. For example, a football tackle without head contact can cause a concussion if the head undergoes rapid acceleration.

The coup-contrecoup mechanism

When your head hits an object, the brain first strikes the skull wall on the side of the impact. This is the "coup." The brain then bounces back and hits the opposite wall. This is the "contrecoup." This double impact explains why symptoms can be felt on both sides of the head.

Rotational forces

Rotational forces are particularly dangerous for the brain. When the head turns rapidly, different parts of the brain move at different speeds. Neurons stretch and twist. This diffuse axonal injury disrupts communication between brain cells.

Side blows to the head produce more rotation than frontal blows. This is why hooks to the face in boxing cause more concussions than direct punches.

What are the symptoms of a concussion?

Concussion symptoms fall into four categories: physical, cognitive, emotional, and sleep-related. The most common symptoms include headaches, dizziness, fatigue, difficulty concentrating, and sensitivity to light. Even a single symptom after an impact is enough to suspect a concussion.

Physical symptoms

Physical symptoms are among the most common:

• Headaches (most common)
• Dizziness or lightheadedness
• Nausea or vomiting
• Excessive fatigue
• Blurred or double vision
• Sensitivity to light (photophobia)
• Sensitivity to noise (phonophobia)
• Balance problems
• Tinnitus (ringing in the ears)

Cognitive symptoms

Cognitive symptoms affect your ability to think clearly:

• Difficulty concentrating
• Memory problems
• Feeling confused or mentally foggy
• Slowness in processing information
• Difficulty finding words
• Slowed reaction time

Emotional Symptoms

Emotional symptoms are very real and are part of the clinical picture of a concussion:

• Irritability
• Sadness or depressive mood
• Anxiety
• Mood swings
• Feeling "not like yourself"

Sleep Disturbances

Sleep is often disrupted after a concussion:

• Sleeping more than usual
• Sleeping less than usual
• Difficulty falling asleep
• Unrefreshing sleep

When do symptoms appear?

Symptoms may appear immediately after the impact or develop gradually over the following hours and days. That is why it is important to monitor a person during the hours and first few days following a potential impact.

Important: Just because you feel fine in the minutes following an impact doesn't mean you haven't sustained a concussion. Never return to play on the same day after a blow to the head.

How is a concussion diagnosed?

A concussion diagnosis is based on the injury history and a clinical examination. There are no lab tests or imaging scans that can confirm a concussion. The evaluation uses validated tools like the SCAT6 to measure symptoms and deficits.

Clinical evaluation

A healthcare professional trained in concussion will ask you about:

• The circumstances of the impact (what, when, how)
• Your current symptoms and how they have changed
• Any loss of consciousness or amnesia
• Your history of concussions
• Your existing health problems

Standardized Assessment Tools

The SCAT6 (Sport Concussion Assessment Tool, 6th edition) is the most widely used assessment tool worldwide.

Additional tests

Your physiotherapist or doctor might perform additional tests:

Vestibular Assessment: To check if the inner ear is affected. Vestibular symptoms (dizziness, nausea with movement) are common after a concussion. Consult our Guide on Vertigo and Dizziness to learn more. Eye Movement Assessment: To check how your eyes are working. Problems with eye teaming (convergence), visual tracking, or quick eye movements (saccades) are common. Neck Assessment: To determine whether the neck is contributing to the symptoms. Whiplash often accompanies a concussion.¹⁰. Check out our guide to theneck sprain to understand this associated injury.

When is imaging necessary?

Imaging tests like CT scans or MRIs do not show concussions. However, they may be necessary to rule out more serious injuries if you have any red flags (see section "When to seek emergency care").

What are the phases of recovery?

Concussion recovery is divided into three phases: the acute phase (relative rest), the subacute phase (gradual return to activity), and the complete recovery phase. Most adults recover within 10 to 14 days. Children and adolescents may take up to 4 weeks.

Phase 1: Relative rest (24 to 48 hours)

The first 24 to 48 hours are^crucial.¹"Relative rest" means:

What You Can Do:

• Light activities that do not significantly increase your symptoms
• Short walks
• Reading for short periods
• Light conversations
• Light cooking

What to Avoid:

• Activities that significantly worsen your symptoms
• Intense sports and physical activities
• Prolonged screen time (television, phone, computer)
• Alcohol and recreational drugs
• Demanding cognitive tasks

Important: Complete rest in a dark room is no longer recommended. Recent studies show that overly strict rest can delay recovery. Stay active within your symptom limits.

Phase 2: Gradual Return (after 24-48 hours without symptoms)

Starting within the first 24 hours after the injury, you can begin a gradual and cautious return to your activities, as long as it does not^{significantly} worsen your symptoms^.¹ This phase follows a step-by-step protocol.

Return to Cognitive Activities:

• Light cognitive activities, gradually increasing the duration as tolerated
• Half-days at school or work
• Full days with accommodations
• Normal return

Return to Physical Activity:

• Walking or stationary cycling (light intensity)
• Jogging or sport-specific exercises (non-contact)
• Team practices (non-contact)
• Full contact practices
• Return to play or competition

Golden Rule: If your symptoms significantly increase at any stage, return to the previous stage and wait 24 hours without symptoms before trying again.

Phase 3: Full Recovery

Most people recover completely. A full return to play or work requires:

• No symptoms at rest or during exertion
• Normal performance on cognitive tests
• Medical evaluation confirming recovery
• For contact sports: authorization from a doctor or physiotherapist

What are the treatment options?

Concussion treatment combines initial rest, a gradual return to activities, and active rehabilitation of affected systems. Specialized physiotherapy addresses the vestibular system, oculomotor system, and neck. Aerobic exercise performed below the symptom threshold can speed up recovery.

Initial relative rest

Relative rest during the first 24 to 48 hours allows the brain to begin healing. Limit intense stimulation while remaining moderately active.

Active Rehabilitation

Scientific understanding has changed: active treatment is now favored over extended rest. Active approaches include:

Aerobic Exercise Below Symptom Threshold: Light physical activity (walking) can begin as early as 24 to 48 hours after the injury, provided it does not significantly worsen the symptoms. A more structured aerobic exercise program can then begin between 2 and 10 days after the injury¹. The intensity must remain below the level that causes symptoms to worsen. Vestibular Rehabilitation: If you experience dizziness or balance problems, specific exercises can help. Eye Movement Rehabilitation: Eye exercises can help treat vision problems and reduce headaches. Neck Treatment: The neck is often injured at the same time as the brain¹⁰. The Physiotherapy for neck pain can significantly reduce headaches and dizziness. If you also have persistent headaches, consult our guide on headaches.

Psychological Treatment

Anxiety, stress, and depressive symptoms are common after a concussion. Psychological support can be part of the treatment plan, especially if symptoms persist.

How Does Physiotherapy Help After a Concussion?

Physical therapy specializing in concussions assesses and treats three key systems: the vestibular system, the oculomotor system, and the cervical spine. Physical therapists trained in concussions can guide patients’ return to activity and significantly speed up their recovery.

The Complete Assessment

Your physiotherapist will conduct a detailed assessment including:

Symptom Assessment: Standardized questionnaires to measure your symptoms and track their progress. Vestibular Assessment: Tests to check how your inner ear is working and to assess your balance. Eye Movement Assessment: Tests for eye movements, convergence, and visual tracking. Neck Assessment: Examination of your neck's mobility, strength, and sensitivity. Exertion Test: Assessment of your exercise tolerance on a treadmill or stationary bike.

Treatment for Vestibular Problems

Depending on the stage and the population, between 30 and 60 percent of people with a concussion experience^vestibular symptoms7^,8. Vestibular rehabilitation involves:

• Gaze stabilization exercises (fixing your eyes on a target while moving your head)
• Habituation exercises (gradual exposure to movements that provoke symptoms)
• Balance training (on unstable surfaces, with eyes closed)

In the only available randomized trial, approximately 73% of patients treated with cervico-vestibular rehabilitation were cleared to return to play within 8 weeks, compared with 7% in the^control group.^⁹

Treatment for Oculomotor Problems

Vision problems are common: difficulty focusing, double vision, light sensitivity. Oculomotor exercises may include:

• Convergence exercises (bringing your eyes closer together)
• Saccade exercises (quickly shifting your gaze)
• Pursuit exercises (following a moving target)

Neck Treatment

Whiplash often occurs alongside a^{concussion.¹⁰} When the brain is subjected to acceleration, so is the neck. Cervical physical therapy includes:

• Joint mobilizations to restore movement
• Releasing tight muscles
• Neck stabilization exercises
• Postural correction

Treating neck pain can significantly reduce headaches and dizziness. For more information, see our guide on neck pain.

Return-to-Play Protocol

Your physiotherapist can supervise your return to sport following a validated protocol. The progressive steps ensure a safe recovery:

Each stage lasts at least 24 hours. If symptoms appear, you return to the previous stage.

Returning to Work or School

Your physical therapist, often in collaboration with your doctor, also plans your gradual return to work or school after your initial time off. They can advise you on the necessary accommodations:

• Limiting the amount of homework and exams at school
• Managing the amount of time spent in front of screens
• Restricting the amount of physical exertion at work

The young person should not be put in stressful situations at school, such as exams or academic catch-up, until they are much better. The main goal of this step is to get used to resuming a schedule, seeing people, and being back in their work or school environment.

What is Post-Concussion Syndrome?

Post-concussion syndrome (PCS) occurs when symptoms persist beyond the normal recovery period. The term “post-concussion syndrome” is generally used when symptoms persist for more than 4 weeks, in both adults and^children.¹ Between 10 and 30 percent of people with concussions develop prolonged symptoms.

Why do symptoms persist?

Several factors can explain why symptoms persist:

Unresolved Vestibular System Injury: If the inner ear remains affected, dizziness and balance issues will continue. Untreated Neck Injury: The neck can continue to contribute to headaches and dizziness. Oculomotor Problems: Uncorrected visual difficulties can maintain symptoms. Autonomic Dysfunction: The autonomic nervous system can remain unbalanced, leading to exercise intolerance. Psychological factors: Anxiety, depression, and post-traumatic stress can amplify and maintain symptoms.

Common Symptoms of PCS

• Persistent headaches
• Chronic Fatigue
• Difficulty concentrating
• Memory problems
• Irritability and mood changes
• Sleep Disorders
• Sensitivity to light and noise
• Dizziness

Treatment for Post-Concussion Syndrome

Treating PCS requires a multidisciplinary approach:

Specialized Physiotherapy: Treatment for vestibular, oculomotor, and cervical components. Sub-threshold Aerobic Exercise: A progressive exercise program that does not trigger symptoms. Psychological Management: Cognitive-behavioral therapy for anxiety and coping strategies. Medical Management: Medication for headaches or other specific symptoms as needed.

The prognosis is generally favorable. Most people with PCS improve with adequate treatment, even if it takes longer.

When to seek medical advice and what are the warning signs?

Consult a healthcare professional as soon as you suspect a concussion. The sooner you seek advice, the faster you will receive the right guidance for recovery. Most concussions are benign, but some symptoms require urgent attention.

Good Reasons to Seek Prompt Consultation

• You have received a blow to the head and are experiencing at least one symptom
• Your symptoms persist after a few days
• Your symptoms prevent you from functioning normally
• You have a history of concussions
• You are an athlete and want to return to your sport

Red Flags: When to Go to the Emergency Room

Certain symptoms may indicate a more serious injury. Go to the emergency room immediately if you observe:

These symptoms are rare but serious. If in doubt, always consult a doctor.

Who to consult?

Concussion-Trained Physiotherapist: Can assess and treat concussions, as well as vestibular and cervical issues, and oversee your return to activities. In Quebec, you can consult without a prescription. Doctor: Can confirm the diagnosis, prescribe medication if needed, and refer you to specialists. Neuropsychologist: Can assess cognitive functions in detail if symptoms persist.

Frequently Asked Questions about Concussion

Is it necessary to lose consciousness to have a concussion?

No. Between 8 and 19 percent of concussions result in a loss of^{consciousness}.^⁶ The presence of even a single symptom following an impact is enough to raise suspicion of a concussion.

How long does a concussion last?

Most adults recover within 10 to 14 days. Children and adolescents may take up to 4 weeks. Approximately 10 to 30% of people experience symptoms that last longer.

Do helmets protect against concussions?

Helmets protect against skull fractures and serious injuries, but they do not prevent concussions. The brain still moves inside the skull during an impact, even when wearing a helmet. However, helmets remain important for preventing more severe injuries.

Can I look at screens after a concussion?

Limit screen time during the first 24 to 48 hours. After this period, you can use screens if it doesn't significantly worsen your symptoms. Start with short periods and gradually increase your usage.

Should I stay in the dark?

No. Complete rest in a dark room is no longer recommended. Rest that is too strict can even delay recovery. Stay lightly active within the limits of your symptoms.

When can I return to sports?

You must be completely symptom-free both at rest and during exertion before starting the return-to-play protocol. A full return to contact sports requires authorization from a healthcare professional.

Is a second concussion more serious?

People who have already had a concussion are at greater risk of having another one. The risk of prolonged symptoms also increases with repeated concussions. That is why it is best to wait until the symptoms have gone away before resuming high-risk activities.

Can physiotherapy really help?

Yes. Studies show that specialized physiotherapy speeds up recovery. Treating vestibular, oculomotor, and cervical components is particularly effective in reducing symptoms and recovery time.

Helmet, Mouthguard, and Prevention

Some protective gear reduces the risk of injury, but not necessarily the risk of a concussion itself.

The helmet

Helmets do not reduce the risk of concussion. They reduce the risk of skull injuries, such as fractures. They are therefore still very important for limiting serious skull injuries, but wearing a helmet does not provide the brain with any additional protection against acceleration.

Wearing a helmet even seems to create a false sense of security in contact sports, which can lead some athletes to use it to make contact. This behavior should be avoided, as it increases the risk of a blow to the head.

Mouthguards

A mouthguard is also not a way to reduce the risk of a concussion. It remains an important and effective way to reduce injuries to the mouth and teeth, whether it is custom-fitted or not.

Related conditions to explore

If you have experienced a concussion, other conditions might be related:

• Cervical Sprain: often associated with concussion during an impact
• Neck Pain: A Complete Guide: the neck often contributes to post-concussion symptoms
• Physiotherapy for Neck Pain: treatments for the cervical component
• Headaches: a common symptom after a concussion
• Vertigo and Dizziness: if you have vestibular issues

Key takeaways

A concussion is a functional brain injury that typically heals within 10 to 14 days. Prolonged complete rest is no longer recommended. Active treatment, including aerobic exercise below the symptom threshold and rehabilitation of the vestibular, oculomotor, and cervical systems, speeds up recovery. Specialized physiotherapy is an effective first-line treatment. Consult a professional quickly after an impact to receive the right advice and optimize your recovery.

Book an appointment with a physiotherapist

If you have experienced a concussion or suspect you have one, don't wait. Our physiotherapists, trained in concussion management, can assess your condition, treat the affected systems, and guide you towards a full recovery.

Make an appointment

References

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2. Schneider KJ, Leddy JJ, Guskiewicz KM, et al. Rest and treatment/rehabilitation following sport-related concussion: a systematic review. British Journal of Sports Medicine. 2017;51(12):930-934.
3. Leddy JJ, Haider MN, Ellis MJ, Willer BS. Exercise is medicine for concussion. Current Sports Medicine Reports. 2018;17(8):262-270.
4. Reneker JC, Moughiman MC, Cook CE. The diagnostic utility of clinical tests for differentiating between cervicogenic and other causes of dizziness after a sports-related concussion. International Journal of Sports Physical Therapy. 2015;10(7):998-1007.
5. Ellis MJ, Leddy JJ, Willer B. Physiological, vestibulo-ocular and cervicogenic post-concussion disorders: an evidence-based classification system with directions for treatment. Brain Injury. 2015;29(2):238-248.
6. National Research Council, Committee on Sports-Related Concussions in Youth. Sports-related concussions in youth: improving the science, changing the culture. National Academies Press; 2014 Feb 4.
7. Ellis MJ, Cordingley D, Vis S, et al. Vestibulo-ocular dysfunction in pediatric sports-related concussion. Journal of Neurosurgery: Pediatrics. 2015;16(3):248-255.
8. Ellis MJ, Cordingley DM, Vis S, et al. Clinical predictors of vestibulo-ocular dysfunction in pediatric sports-related concussion. Journal of Neurosurgery: Pediatrics. 2017;19(1):38-45.
9. Schneider KJ, Meeuwisse WH, Nettel-Aguirre A, et al. Cervicovestibular rehabilitation for sports-related concussion: a randomized controlled trial. British Journal of Sports Medicine. 2014;48(17):1294-1298.
10. Gil C, Decq P, et al. How similar are whiplash and mild traumatic brain injury? A systematic review. Neurochirurgie. 2021;67(3):238-243.