Persisting Symptoms
After Concussion
Previously called Postconcussion syndrome (PCS)
Symptoms that persist for more than 4 weeks after a concussion are considered persisting symptoms; it is important to seek rehabilitative treatment for these symptoms. Between 10–30% (approximately one-third) of concussion patients experience persisting symptoms post-concussion.
Contents
Overview
Are we talking about “Persisting symptoms after concussion” or “post-concussion syndrome”?
You may have heard of post-concussion syndrome (PCS), which used to be the common term for describing persisting concussion symptoms, but that has changed. The term that is now used internationally by researchers and clinicians is persisting symptoms after concussion (PSaC). The reason the term post-concussion syndrome is no longer used is that the term “syndrome” means a group of symptoms that always occur together. In contrast, a concussion is what is called a heterogeneous injury–each person who sustains a concussion will have a different combination of symptoms. Some symptoms are more common than others; for example, headache after a concussion is the most common symptom.
A concussion is a brain injury
A concussion is a mild traumatic brain injury that can occur when the head, neck, or body experiences a jolt or blow, resulting in an impulsive force being transmitted to the brain that causes the brain tissue to stretch, compress, and twist inside the skull.
This tissue movement causes a cascade of temporary chemical changes in the brain and can stretch and damage brain cells—often on a level that is too small to see on standard imaging tests. These chemical and physical changes cause symptoms that can affect how a person thinks, feels, acts, learns, and sleeps.
Timeframe for persisting symptoms
According to the most recent international consensus, symptoms persisting after 4 weeks are considered persisting symptoms.
How common is it to develop persisting symptoms?
Researchers have reported varying percentages of people with concussions who then develop prolonged symptoms, but the most common statistic is that 10-30% of concussion patients develop persisting symptoms. A 2018 study estimated that between 11.4% and 38.7% of people with concussions will develop persisting symptoms.
A 2022 study found that “50% reported three or more symptoms at a year after their injury, and >70% reported at least one problematic symptom.”
A 2016 study found that approximately one-third of pediatric concussion patients experience persisting symptoms.
A 2014 study explains that "By the age of sixteen, one in five children will sustain a mild traumatic brain injury (concussion). Our research found that one in seven school children with mild traumatic brain injury suffer postconcussion syndrome symptoms for three months or longer." Another 2014 study approximated that "10% to 20% of individuals" develop postconcussion syndrome.
“Evidence across multiple biomarker domains suggests that a time window of physiological change may extend beyond clinical recovery (ie, resolution of clinical signs and symptoms)”, meaning that the patient appears well to their doctor but may still be experiencing the physiological effects of their injury. There is ongoing research into physiological changes that persist beyond clinical recovery, though it is not yet known whether these changes interact with the recovery process or return to daily life. These physiological changes can include neuroinflammation, impaired autonomic function, and other changes outside of clinical signs and symptoms.
When to seek care for persisting syptoms
Individuals with persisting symptoms should be evaluated and then receive rehabilitative care
If symptoms are persisting, worsening, or not resolving, seek care between 2-4 weeks after concussion. Ask for a referral to a concussion clinic or an outpatient rehabilitation clinic; learn more about these clinics here. In general, a concussion patient with persisting symptoms needs individualized treatment covering the multiple body systems that may be involved.
A comprehensive assessment should come first, one that identifies issues within the different symptom domains. In other words, what type of symptoms do you have (physical, cognitive, sleep, etc.), and what might be contributing to these symptoms?
Once the assessment is done, you should be referred for rehabilitation, such as physical therapy or occupational therapy. Some symptoms should be treated before others. For example, neck issues should generally be addressed immediately, before vestibular symptoms such as dizziness: read more about this on our Physical Therapy page.
You may be referred to a neurologist to help with headaches; learn more about headaches after a concussion. You may be referred to a neuropsychologist to assess you for cognitive issues such as memory and attention problems; after being assessed, a speech-language pathologist may work with you to do cognitive rehabilitation. Or you may be referred to a mental health professional to help with mental health issues after a concussion, such as anxiety or depression.
Click here or on the images below to download a PDF of this flier.
In some cases, seek treatment for symptoms as soon as the second week after your concussion
Neck pain, headaches, and/or dizziness: if these symptoms last more than 10 days post-concussion, see a physical therapist for cervicovestibular (neck and vestibular) rehabilitation. See our resources on Physical Therapy and Vestibular Therapy for more information.
Sleep disturbance: If you have “sleep disturbance in the 10 days after” a concussion, see a sleep specialist for evaluation and treatment. See our resource Sleep and Sleep Problems.
Vision problems after a concussion: After 4 weeks, referral to a specialist in diagnosing concussion-related vision issues may be necessary; see our Vision Therapy resource.
Mental health issues: If you experience new or worsening mental health problems, including symptoms of anxiety, depression, or PTSD, contact a mental health professional to seek care as soon as possible. Concussions can affect your mental health both through the physical injury itself and the difficulty of navigating symptoms during recovery. See our resources Mental Health, Mental Health Among High Schoolers, and The Invisible Injury. We also recommend this flyer on mental health challenges after a concussion here.
More about where to get treatment for persisting treatments
Ask for a referral to a clinic that will do a comprehensive evaluation to identify issues within the different symptom domains (physical, cognitive, sleep) and then will create a treatment plan that may include physical therapy, cognitive rehabilitation, referrals to mental health specialists, etc.
Some concussion clinics have these resources. However, sometimes the best option is to get a referral to an outpatient rehabilitation clinic affiliated with a hospital. These clinics typically have many of the specialists necessary for concussion treatments, such as physical therapist, occupational therapists, speech language pathologists (SLP), etc. See our resource, Concussion and Rehabilitation Clinics.
Four categories of persisting symptoms and how to seek care
Each person with persisting symptoms will have their own unique cluster of symptoms.
Individuals with persisting symtoms should receive an assessment in a clinic; the assessment should cover all the different systems in the body that may be affected by the concussion.
Physical
Headache or "pressure" in the head (the most common symptom)
Neck pain
Sensitivity to light and sound
Dizziness or balance problems
Tired, no energy, drowsiness
Fuzzy, double, or blurry vision
Trouble with reading or looking at screens
Reduced tolerance to stress, emotional excitement, or alcohol.
Slurred speach
Ringing in the Ears
Decreases in taste and smell (a rare symptom)
If you have neck pain, dizziness, or headaches that persist beyond the first week:
Seek cervicovestibular therapy or vestibular therapy with a physical therapist.
Read our interview with a vestibular therapist and how she works with concussion patients with persisting symptoms:
Medication to help with headaches, sleep issues, or challenges with mood is sometimes appropriate. Learn more about medications in our Medications and Neurologist resources.
If you have vision problems that persist for more than 4 weeks, including trouble reading and looking at screens:
Seek vision therapy; see our Vision Therapy resource.
Cognitive
Difficulty with memory
Difficulty recalling events & information
Difficulty with attention
Getting distracted easily and having difficulty with focus and concentrating
Difficulty with thinking clearly
Simple tasks now feel difficult
Confusion
Feeling slowed down, mentally “foggy”
If you have difficulty with concentrating, thinking clearly, or memory persists for more than 4 weeks:
Seek assessment and cognitive rehabilitation from a neuropsychologist or speech-language pathologist. Often these specialists work at outpatient rehabilitation clinics–learn more.
To learn more about cognitive dysfunction after a concussion, assessment, rehabilitation, and the types of healthcare providers who can help:
Sleep
Sleeping less
Trouble falling asleep
Irregular sleep patterns
Waking up feeling unrested
Fatigue during the day
Sleeping more than usual (common with a recent concussion)
If you have problems with sleep that persist for the first 10 days after a concussion or longer, it’s important to see a sleep specialist. See our resource on Sleep and Sleep Problems.
Mood/Behavioral
A concussion patient can develop new mood and behavioral challenges after a concussion, or their pre-existing mental health issues may increase or change.
Increased Irritability
Becoming frustrated or upset more easily
Increased depression or anxiety
Feeling worried, sad, or hopeless
More emotional
Crying more easily or feeling overwhelmed
Increased apathy or lack of motivation
Seek care as soon as possible for issues related to mental health. Learn more about mental health challenges after a concussion, how to find help, and types of treatments, such as cognitive behavioral therapy. We have several resources with information.
What makes a person more vulnerable to persisting symptoms?
Who you are
Children 8-12 years old
Teenagers 13-18 years old
Elderly adults
Women
Your medical history
A history of previous concussion(s)
Symptoms lasted longer than one week (previous concussion)
A history of mood, anxiety, learning or seizure disorder
A history of migraines
The nature of the concussion
severe impact
double impact (hit twice in a short timeframe)
four or more concussion symptoms in the very early stage of the concussion
duration of the initial concussion symptoms
major visual symptoms soon after injury
CLICK ON THE IMAGE TO SEE A LARGER VERSION OF THIS CHART.
March 8, 2016, "Clinical Risk Score for Persistent Postconcussion Symptoms Among Children with Acute Concussion in the ED". "Sx duration" means symptom duration. "BESS" refers to Balance Error Scoring System.
What are the physical causes of persisting symptoms?
The medical community has a good understanding of what happens with the brain with the initial concussion but does not have a clear consensus regarding the explanation for prolonged symptoms.
Researchers and clinicians agree that concussions involve "neuronal dysfunction, cell death and altered connectivity including oxidative stress, metabolic dysfunction, neuroinflammation, axonal damage and alterations in cerebral blood flow." In terms of what is creating postconcussion syndrome, recent research points to "alterations in neuronal circuitry and neurotransmission."
According to the University of Calgary and Université Laval’s Massive Open Online Course (MOOC) on concussions, the causes for postconcussion syndrome can include:
unresolved concussion
headache syndromes
injury to the neck
vestibular dysfunction
autonomic dysfunction
sleep disorder
underlying anxiety/depression
Assessment for persisting symptoms
Various systems in the body can be affected by persistent symptoms, so an assessment for persisting symptoms needs to be broad and comprehensive. Additionally, a collaborative approach between different specialists is often needed in these cases.
This section draws in part from a 2025 virtual presentation by Sara Etheredge, PT, DPT, CKTP, CCI, CMTPT, AIB-VRC
History
Your doctor will ask questions about
the specific incident that caused the concussion
symptoms felt at the time of the injury and how they have changed over time
previous history of migraines/headache, neck pain, sleep problems, anxiety, medications, etc.
Questionnaire and screening tools
Your doctor may have you take a symptom questionnaire, such as the Concussion Clinical Profiles Screening Tool. This questionnaire will help your physician understand your symptom profile. Symptom profiles include cognitive-fatigue, ocular (eye), vestibular (balance or dizziness), mood (such as anxiety or depression), cervical (neck), and migraine.
Your doctor may have you take one or more psychosocial screenings (questionnaires) to assess for emotional and mood disturbances, such as anxiety or depression.
Examination
Your doctor, physical therapist, or other concussion specialist may check your:
neck function, such as movement, tenderness, strength, etc. See our resource on Physical Therapy for more information about the neck.
balance and vestibular function. See our resource on Vestibular Therapy.
how your eyes are functioning, called oculomotor function: this includes how well your eyes track an object side to side, how well they focus on an object as it gets close to your eyes, etc. See our resource on Vision Therapy.
autonomic nervous system (ANS): check for problems with the ANS, including tests of orthostatic vitals, heart rate variability testing, 10-minute stand test, marching test. See our resource Autonomic Nervous System Dysfunction.
brain function (memory, ability to process information, reaction times, etc.)
special tests may sometimes be required
graded aerobic exercise test, such as the Buffalo Concussion Treadmill, Bicycle, or Marching Tests for assessment of exercise tolerance. Read more on our Graduated Exercise Therapy page.
formal neuropsychological testing to further assess brain function. Read more about neuropsychological testing here.
Neuroendocrine screening for hormone imbalances, see our resource on Hormone Therapy.
test for benign paroxysmal positional vertigo (BPPV)
Conventional Imaging
CT and MRI scans are usually normal for concussions. Since CTs expose the patient to radiation and MRIs are expensive, doctors use these imaging methods sparingly.
A CT or MRI may be used to rule out underlying structural brain injury, such as a brain bleed (hematoma).
ultimately, imaging can be used to help reassure your doctor that they are not missing a structural injury such as bleeding in the brain.
Advanced Investigation Techniques: only available to researchers
PET scans, functional MRI, Blood biomarkers, etc.
all advanced investigation techniques show '“changes” in concussed individuals when compared to non-injured “controls”
**This section on advanced investigation techniques summarizes information from the University of Calgary and Université Laval’s Massive Open Online Course (MOOC) on concussions
Are persisting symptoms related to how severe your concussion was?
According to the Mayo Clinic, "the risk of developing persistent post-concussive symptoms doesn't appear to be associated with the severity of the initial injury." Individuals who do not lose consciousness during an impact are still prone to getting a concussion and/or postconcussion syndrome. (Many of the people we know with PCS did not lose consciousness when they were concussed.)
However, numerous studies do show a relationship between the severity of early concussion symptoms (within 24 hours) and longer recovery times. For example, a study of high school and college athletes with concussions found that loss of consciousness, amnesia about events before and after the concussion, and greater symptom severity within the first 24 hours following injury were associated with longer recoveries (7 or more days). (2014)
Another study showed that individuals who had four or more concussion symptoms were at double the risk of prolonged symptoms. (2014)
Prognosis for recovery from persisting symptoms
Dr. Elizabeth Sandel says, "The prognosis for PCS is good. It’s believed that around 50% of people with a history of mTBI (mild traumatic brain injury) or concussion are still experiencing symptoms three months after their injury, and at a year that number has dropped to 10–15%, meaning that the majority of the symptoms go away within a year of the injury. (It should be noted that these numbers are debated and no number has the full consensus of experts.)" (Shaken Brain: The Science, Treatment, and Care of Concussion
The Centers for Disease Control & Prevention (CDC) notes that "A person with a history of multiple or repeated mild TBIs or concussions may experience a longer recovery or more severe symptoms.” Additionally, they may have “ongoing problems with concentration, memory, and headache,” along with problems in “keeping one’s balance.”
Girls are known to be at a higher risk for concussions and have longer recovery times than boys, but the longer recovery times might be because they are taken to see a specialist later than boys. According to a 2019 study, the longer recoveries and more symptoms can be attributed to girls seeking specialist care more than a week later than boys, but if they seek care at the same time that boys tend to (within 7 days after the concussion), they have no differences in recovery times when compared with boys.
See our page on Guidelines to Recovery (under “Seek Care for Persisting Symptoms.”)
Persisting symptoms and how they can affect your life
We’ve gone into depth on how prolonged symptoms can affect your life in our pages on The Invisible Injury and Mental Health.
Persisting emotional symptoms are caused by multiple factors
A person who sustains a concussion is at increased risk for emotional (mood) symptoms after a concussion. This risk for emotional symptoms increases if you develop persisting symptoms after a concussion. There are primary and secondary factors for emotional symptoms after a concussion.
Primary factors for emotional symptoms after a concussion
Emotional symptoms are due to the concussion itself, such as irritability, mood instability (mood lability)
Secondary factors for emotional symptoms after a concussion
All the difficulties around concussion being an invisible injury: see Invisible Injury resource.
Uncertain timelines for when you will be fully recovered, when you can return to sport
Social impacts, for example, social isolation, missing out on sports or activities
Academic impacts on grades, SAT testing, and scholarship opportunities
Work impacts such as missing work, potential job loss, reduction or loss of income, loss of social connections at work
The resource for this section is from a 2025 clinical webinar presented by Christina L. Master, MD, FAAP, CAQSM, FACSM, and the Minds Matter Concussion Program at the Children’s Hospital of Philadelphia.
Related blog posts
Results from a recent study published in the Clinical Journal of Sports Medicine indicated that youth with exercise-induced vision dysfunction following sport-related concussion were at “a 3-folder greater risk” of developing persistent post-concussive symptoms (PPCS) compared to those without exercise-induced vision dysfunction.