Persistent Symptoms After Concussion

Also called Postconcussion syndrome (PCS) or Persistent Post-Concussive Symptoms (PPCS)

Overview

Prolonged symptoms: different terms in use

There are different definitions of prolonged symptoms, including post-concussion syndrome (PCS) and persistent post-concussive symptoms (PPCS). The newest term, used by the most recent international consensus, is persisting symptoms after concussion (PSAC).

Timeframe for prolonged symptoms

According to the most recent international consensus, symptoms persisting after 4 weeks are considered persisting symptoms, and these patients would be referred to multidisciplinary care.

Incidence of prolonged symptoms

Researchers have reported varying percentages of people with concussions who then develop prolonged 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 2018 study estimated that between 11.4% and 38.7% of people with concussions will develop postconcussion syndrome.

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.

"Recent literature suggests that the physiological time of recovery may outlast the time for clinical recovery,” meaning that the patient appears well to the doctor overseeing her case. "The consequence of this is as yet unknown, but one possibility is that athletes may be exposed to additional risk by returning to play while there is ongoing brain dysfunction."

Prolonged symptoms fall into four categories:

Except for their persistence, the types of symptoms people may experience with postconcussion syndrome are the same as those experienced in the immediate/early stage of a concussion.

Each person with prolonged symptoms will have their own unique cluster of symptoms.

Physical

  • Headache or "pressure" in the head (the most common symptom)

  • Neck pain

  • Light-headedness

  • Sensitivity to Light

  • Sensitivity to Sound

  • Ringing in the Ears

  • Balance problems, dizziness

  • Fatigue

  • Fuzzy, double, or blurry vision, trouble with reading

  • Rarely, decreases in taste and smell

  • Reduced tolerance to stress, emotional excitement, or alcohol.

Cognitive

  • Difficulty with memory, or remembering new information

  • Difficulty with attention

  • Difficulty with thinking clearly

  • Difficulty with focus or concentrating

  • Confusion

  • Feeling slowed down mentally

Sleep

  • Sleeping more than usual (most common with a recent concussion)

  • Sleeping less than usual, or trouble falling asleep (typically when more time has elapsed since the concussion)

  • Sleep disturbance (sleep cycle is interrupted)

Mood/Behavioral

  • Irritability that didn't exist before the concussion

  • Sadness or depression that didn't exist before the concussion

  • Anxiety or nervousness that didn't exist before the concussion

  • More emotional

  • Apathy that didn't exist before the concussion

    **these mood/behavioral symptoms could be pre-existing and made worse/altered by the concussion

What makes a person more vulnerable to prolonged symptoms?

Who you are

  • Children 8-12 years old

  • Teenagers 13-18 years old
    There is some evidence that the teenage years, particularly the high-school years, might be the most vulnerable time period for having persistent symptoms—with greater risk for girls than boys.

  • 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 prolonged 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

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 prolonged symptoms

Various systems in the body can be affected by persistent symptoms, so an assessment for PCS needs to be broad and comprehensive. Additionally, a collaborative approach between different specialists is often needed in these cases.

History

  • 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.

Examination

  • targeted to focus on the key domains identified in history

  • may include assessment of

    • neck (movement, tenderness, strength, etc.)

    • balance and vestibular function

    • eye movement and vision

    • brain function (memory, ability to process information, reaction times, etc.)

  • special tests may sometimes be required

    • graded aerobic exercise test for assessment of exercise tolerance

    • formal neuropsychological testing (to further assess brain function)

    • other

Conventional Imaging

  • may be used to rule out underlying structural head injury

  • CT/MRI are usually normal or show incidental changes in the brain

  • ultimately they can be used to help reassure that specialists are not missing an underlying structural head injury

Advanced Investigation Techniques

  • PET scans, functional MRI, Blood biomarkers, etc.

  • all show '“changes” in concussed individuals when compared to non-injured “controls”

  • some have promising early results, but the research design is limited

  • these techniques are only available to researchers at this point

**This section summarizes information from the University of Calgary and Université Laval’s Massive Open Online Course (MOOC) on concussions

Are prolonged 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). Another study showed that individuals who had four or more concussion symptoms were at double the risk of prolonged symptoms.

Prognosis for recovery from prolonged 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.)"

The Center for Disease Control & Prevention notes that "In general, recovery may be slower among older adults, young children, and teens. Those who have had a concussion in the past are also at risk of having another one. Some people may also find that it takes longer to recover if they have another concussion."

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 rehabilitation/treatment for persistent symptoms”)

Treatment for prolonged symptoms

"Treatment of PCS typically focuses on relieving the individual symptoms, as the underlying cause of PCS isn’t known and therefore can’t be addressed as a condition, like giving an antibiotic for pneumonia, for example. However, both medication and non-medication therapies are used to treat individual PCS symptoms."

Common treatments for PCS include:

  • Physical Therapy:

    • This involves guided rehabilitative exercises with a physical therapist in order to reintegrate the patient into daily activities and combat symptoms.

    • See our page on Physical Therapy and Vestibular Therapy for more information

    • The Concussion Legacy Foundation recently hosted a webinar, How Physical Therapy Can Treat Post-Concussion Syndrome.

    • For additional information, read our blog post detailing the importance of telehealth and vestibular therapy with Sara Gallagher. 

  • Other Types of Treatments Recommended by the 5th Consensus on Concussion in Sport 

  • Light Therapy (Photobiomodulation)

    • *This therapy is currently being researched and there isn’t definitive evidence for its efficacy

    • This type of therapy uses devices that deliver LED lights in the form of visible red light and near-infrared wavelengths to aid in the healing process.

    • See our blog post outlining an eight-week case study for a home-use light therapy treatment that showed improvements in brain structure and function.

A 2016 study that used collaborative care (which “integrates medical and behavioral health care for patients with chronic disorders in which both physical and psychological symptoms are present”) for adolescent patients with persistent postconcussive symptoms showed a statistically significant reduction in symptoms (78% reduction in the treatment group versus 45.8% reduction in the control group) over six months.

Patients with consistently occurring symptoms that do not resolve may refer to a neurologist and get an MRI to confirm that there is no permanent physical damage in the brain before continuing to treat individual symptoms.

See our Treatment section to learn about rehabilitative, medical, complementary & alternative therapies and self-care for postconcussion syndrome.

Prolonged symptoms and how they can affect your life

We’ve gone into depth into how prolonged symptoms can affect your life in our pages on The Invisible Injury and Mental Health.

Postconcussion syndrome “can result in significant physical, emotional, and cognitive stress,” according to momsTeam.

PCS “can be extremely disruptive to a patient’s life. In addition to having to constantly manage concussion symptoms, which can intensify with normal activity, long-term PCS patients often have to restructure their lives to avoid activities and situations that cause symptoms to worsen. For children, this can mean extended absences from school and removal from sports and extra-curricular activities. In severe cases, it may be necessary for a child to repeat a grade. In adults, PCS can seriously impact a patients’ personal and professional life, interfere with family life, as well as the ability to focus, communicate, and be effective at work."

Resources