Concussion

Question 1

1. What is a concussion?

Answer 1

A concussion is a type of traumatic brain injury caused by a direct blow to the head, neck, or body that results in an impulsive force being transmitted to the brain. This leads to a complex pathophysiological process affecting the brain, often involving a neurotransmitter and metabolic cascade, potential axonal injury, changes in blood flow, and inflammation (Patricios et al., 2023). For example, a soccer player who collides with another player and experiences a sudden jolt to the head may sustain a concussion.

Question 2

2. What are the rates and incidences of concussions in the general population versus in sports?

Answer 2

In Canada, approximately 1 in 450 individuals aged 12 and older reported a sport-related concussion (SRC) as their most significant injury with associated disability in the previous year (Gordon & Kuhle, 2022). In Ontario, there was an average incidence of 1,153 concussions per 100,000 residents between 2008 and 2016 (Langer et al., 2020). The prevalence of SRCs increased nearly 2.5 times from 2005 to 2013, with higher rates among youth aged 12-19 compared to adults over 19 years old (Gordon & Kuhle, 2022). This highlights the increased risk of concussions in sports compared to the general population.

Question 3

3. What are the symptoms of concussions?

Answer 3

• Concussion symptoms can be classified into four clusters:
• Somatic: headache, neck pain, nausea, dizziness, blurred vision, balance problems, sensitivity to light and noise.
• Cognitive: feeling slowed down, in a fog, difficulty concentrating, difficulty remembering, confusion.
• Arousal/Sleep problems: fatigue, drowsiness, trouble falling asleep.
• Emotional: irritability, sadness, nervousness, anxiety (Echemendia et al., 2017).
  For instance, a football player who sustains a concussion may experience a headache, dizziness, and difficulty concentrating in the days following the injury.

Question 4

4. What is the difference between a concussion and sport-related concussion?

Answer 4

A sport-related concussion (SRC) is a subset of concussions that occur specifically during sports or exercise-related activities. SRCs are characterized by the same pathophysiological processes as general concussions but are distinct due to their occurrence in a sporting context, necessitating specific management and return-to-play protocols tailored for athletes (Patricios et al., 2023). For example, a hockey player who sustains a concussion during a game would be diagnosed with an SRC and would follow sport-specific guidelines for recovery and return to play.

Question 5

5. How often do athletes typically sustain SRCs and what are the most common circumstances leading up to it?

Answer 5

Athletes, particularly in contact sports, have a higher incidence of SRCs. In Ontario, hockey accounted for the highest number of SRCs (44.3%), followed by soccer (19.0%) and football (12.9%) (Cusimano et al., 2013). Circumstances leading to SRCs often involve high-impact collisions, falls, or blows to the head during sports activities. For instance, a hockey player may sustain an SRC due to a body check or a soccer player may experience a concussion from a collision with another player or the ground.

Question 6

6. How are concussions objectively tracked and measured?

Answer 6

• Concussions are tracked and measured using a combination of subjective symptom reports and objective clinical assessments. Tools such as the Sport Concussion Assessment Tool (SCAT-5) provide standardized methods for evaluating symptoms, cognitive function, and neurological status. Neurocognitive tests like the Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT™) battery assess cognitive functions such as attention, memory, processing speed, and reaction time (Allen & Gfeller, 2011). Advanced imaging techniques like diffusion tensor imaging (DTI) and functional MRI (fMRI) can also provide insights into brain changes post-concussion.
• Moreover, accelerometers and gyroscopes located in helmets or mouthguards can be used to gather real-time data on head impacts encountered by athletes during play. These devices measure the acceleration forces and rotational velocities experienced by the head, providing objective data on the magnitude and direction of impacts. This information can help in identifying potentially concussive blows and contribute to a better understanding of the biomechanics involved in concussions.

For example, an athlete who sustains a concussion would complete the SCAT-5 and ImPACT™ tests to objectively measure their symptoms and cognitive function, which could be supplemented by data from accelerometers to understand the impact forces involved in the injury. This comprehensive approach helps clinicians make more informed decisions about diagnosis and management.

Question 7

8. What is the process of getting an SRC diagnosis?

Answer 7

• Diagnosing a sport-related concussion (SRC) involves a multi-step and multi-domain approach, integrating clinical evaluations, symptom reporting, cognitive testing, and sometimes neuroimaging. The process is designed to ensure a thorough and accurate assessment to guide appropriate management and return-to-play decisions.
• 1. Immediate Evaluation and Initial Assessment
• On-Field Examination
  ○ Primary Survey: Immediately after a suspected head injury, the focus is on primary survey protocols — checking airway, breathing, circulation, and conducting a spinal evaluation to rule out any severe injuries.
  ○ Observable Symptoms: The clinician will look for signs such as unconsciousness, confusion, balance issues, and other neurological symptoms.
  ○ Brief Cognitive and Physical Assessments: Tools such as the sideline concussion assessment tool (part of SCAT-5) help in initial assessment. This includes orientation questions (e.g., “What venue are we at?”, “Which half is it?”), immediate memory tests, and a brief neurological examination.
• Removal from Play
• If an SRC is suspected, the athlete is immediately removed from play to prevent further injury and to allow for a more comprehensive evaluation.
• 2. Comprehensive Clinical Evaluation
• Detailed History Taking
  ○ Mechanism of Injury: Understanding how the injury occurred, including the forces involved and any previous history of concussions, is critical.
  ○ Symptom Timeline: Documenting when symptoms appeared, their severity, and any changes over time.
• Comprehensive Symptom Evaluation
  ○ Symptom Checklists: The SCAT-5 includes a symptom scale where athletes rate 22 symptoms (like headache, dizziness, nausea) on a severity scale. This provides a quantitative tool to track symptom progression.
  ○ Daily Activities Impact: Evaluating how symptoms affect daily activities, such as school or work, helps gauge the concussion’s impact on the individual’s functionality.
• 3. Cognitive Function Testing
• Standardized Tests
  ○ SCAT-5 Cognitive Components: This includes orientation questions and memory tests involving word recall and concentration tests like digit span tasks.
  ○ Computerized Neurocognitive Testing (e.g., ImPACT™): These tests measure domains such as memory, processing speed, reaction time, and attention. ImPACT™ involves baseline testing for comparison post-injury, offering a reliable method to identify cognitive impairments.
• Clinical Neuropsychological Assessment
• For complex cases, detailed neuropsychological testing assesses cognitive deficits more comprehensively, examining domains such as executive function, language, and visual-spatial skills.
• 4. Physical and Neurological Examination
• Balance and Coordination Assessments
  ○ Balance Error Scoring System (BESS): This test involves the athlete performing a series of balance tasks, with errors in performance recorded.
  ○ Vestibular/Oculomotor Screening (VOMS): Evaluates balance and eye movements, including smooth pursuits, saccades, convergence, and the vestibulo-ocular reflex (VOR).
• Neurological Exam
• A full neurological examination checks cranial nerves, strength, sensation, reflexes, and coordination to rule out more serious neurological conditions.
• 5. Advanced Diagnostics (Optional)
• Neuroimaging
  ○ CT Scans and MRI: While not typically used for routine SRC diagnosis, these can be essential if structural brain damage or other emergencies (e.g., skull fracture, intracranial hemorrhage) are suspected.
  ○ Functional Imaging (e.g., fMRI, DTI): Cutting-edge imaging techniques like functional MRI (fMRI) and diffusion tensor imaging (DTI) can provide insights into brain function and structural connectivity. These are generally used in research settings or complex clinical cases.
• Biomarkers
  ○ Blood and CSF Biomarkers: Research is ongoing into specific biomarkers that could indicate brain injury, such as tau proteins or neurofilament light, although routine clinical use is currently limited.
• 6. Integration of Data and Diagnosis
• Combining clinical findings, symptoms, cognitive and physical assessments, and any additional data like imaging results, the clinician makes an informed diagnosis.
• Differential Diagnosis
• It is essential to rule out other medical conditions that may present similarly to concussions, such as neck injuries, psychological conditions, or other neurological disorders.
• 7. Patient and Family Education
• Educating the athlete and their family about the nature of the injury, expected symptoms, recovery trajectory, and the importance of adhering to prescribed management plans is crucial. This includes providing information about signs of worsening symptoms that necessitate immediate medical attention.
• 8. Follow-up and Monitoring
• Regular Follow-up
  ○ Symptom and Cognitive Monitoring: Reassessing symptoms and cognitive function regularly to track recovery and identify any persisting issues.
  ○ Engagement in Rehabilitation: If symptoms persist, involving physical therapists, cognitive rehabilitation specialists, or other professionals as needed.
• Return-to-Play Protocols
  ○ Stage-based Rehabilitation: Following the graduated return-to-play protocol, progressing from symptom-limited activities to full sport-specific exercise under healthcare provider supervision.
  ○ Final Clearance: Only when the athlete remains symptom-free at rest and with exertion, has normal cognitive function, and has no neurological deficits, is full return to play considered appropriate.
• The diagnosis and management of SRCs require a multidisciplinary approach and individualized care to ensure a safe and successful recovery.

Question 8

9. What are some of the most popular diagnostic tools for SRCs and what do they entail?

Answer 8

• Popular diagnostic tools for SRCs include:
• Sport Concussion Assessment Tool (SCAT-5): Evaluates symptoms, cognitive function, and neurological status.
• Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT™): Assesses cognitive functions such as attention, memory, and reaction time.
• Vestibular and oculomotor screening: Assesses balance and eye movements (Echemendia et al., 2017; Allen & Gfeller, 2011).
• These tools provide a comprehensive evaluation of the various domains affected by SRCs and help healthcare providers make accurate diagnoses and treatment plans.

Question 9

Describe the SCAT-5 in detail.

Answer 9

• The SCAT-5 includes several components:
• Immediate/on-field assessment: Evaluates immediate symptoms and observable signs following an injury using questions about the mechanism of injury and observable signs such as loss of consciousness or balance disturbances.
• Symptom evaluation: Assesses the frequency and severity of 22 symptoms (e.g., headache, dizziness, nausea) on a 7-point Likert scale, to quantify the athlete’s experience post-injury.
• Cognitive screening: Includes orientation questions (e.g., asking the date), immediate memory recall tests (e.g., word lists), and concentration tests (e.g., digit span).
• Neurological Screening: Assesses balance using the modified Balance Error Scoring System (mBESS), coordination tests (e.g., finger-to-nose), and delayed recall of memory items.
• Delayed recall: Tests memory 5-10 minutes after the initial memory test to evaluate short-term memory retention.
• The SCAT-5 is designed to provide a comprehensive evaluation of the domains affected by SRCs (Echemendia et al., 2017). For example, the immediate/on-field assessment would be used to evaluate an athlete’s symptoms and cognitive function immediately after a suspected concussion, while the symptom evaluation and cognitive screening would be used to track their recovery over time.

Question 10

What is the current return-to-sport protocol?

Answer 10

• The current return-to-sport (RTS) protocol involves a graduated, stepwise approach consisting of six stages:
• Symptom-limited activity: Activities of daily living that do not provoke symptoms.
• Light aerobic exercise: Gentle aerobic activities like walking or stationary cycling at slow to medium pace. No resistance training.
• Sport-specific exercise: Running or skating drills without head impact activities.
• Non-contact training drills: More complex training drills, such as passing drills or practice activities without direct contact. May start progressive resistance training.
• Full-contact practice: Following medical clearance, participate in normal training activities.
• Return to sport: Normal game play.
• Progression through each stage depends on the absence of symptom exacerbation and the athlete’s clinical status (Patricios et al., 2023). For instance, an athlete who sustains a concussion would begin with symptom-limited activity and gradually progress through each stage as their symptoms improve and they demonstrate tolerance for increased physical and cognitive demands.

Question 11

12. How has research supporting strict rest post-SRC shifted to the current support for graded aerobic exercise and relative rest with symptom-limited physical activity?

Answer 11

Existing research suggests that strict rest may not be beneficial for recovery following a concussion. A randomized controlled trial by Thomas et al. found that strict rest after acute concussion did not provide additional benefits compared to a more gradual return to activity (Thomas et al., 2015). Furthermore, a case-control study by Silverberg demonstrated that advising individuals to rest for more than 2 days after mild traumatic brain injury was associated with delayed return to productivity (Silverberg, 2019).

In contrast, recent work has suggested that light to moderate exercise can have positive effects on cognitive function and symptom improvement in individuals with traumatic brain injuries.

Chin et al. examined cognitive function in individuals with mild-to-moderate chronic traumatic brain injury. Participants who engaged in treadmill exercise three times per week for 30 minutes at 70-80% of their heart rate reserve demonstrated significant improvements in processing speed and executive function following the exercise training (Chin et al., Year).

Additionally, Leddy et al. found that male adolescents with sports-related concussions who engaged in early prescribed aerobic exercise experienced better recovery outcomes compared to those who were advised to rest. The exercise group had significantly fewer participants who remained symptomatic in physical, cognitive, and sleep domains (Leddy et al., Year).

Similarly, Dematteo et al. evaluated the response of youth with persistent post-concussive symptoms to an exertion test involving gradual increases in cycling workload. Participants experienced significant improvements in cognitive-sensory, affective, and sleep-arousal symptoms following the acute exercise assessment and 24 hours later (Dematteo et al., Year).

Collectively, these findings suggest that light to moderate exercise may be more beneficial than strict rest in promoting recovery and symptom resolution following a concussion. Individualized approaches to activity resumption based on the type and severity of concussion are recommended (Silverberg, 2013).

Question 12

At which stage is physical activity, specifically exercise safe for a person with an SRC?

Answer 12

Physical activity is safe during the symptom-limited activity stage, which is the first stage of the RTS protocol. Light-intensity activities such as walking or stationary cycling are recommended within 24-48 hours post-injury, provided they do not exacerbate symptoms beyond mild levels (Patricios et al., 2023). Early engagement in gentle, non-strenuous activities helps mitigate the negative effects of prolonged rest and supports physical and psychological recovery. For instance, an athlete who sustains a concussion may be advised to take short walks, engage in light stretching exercises, or perform mild stationary biking within the first few days of the injury, as long as these activities do not worsen their symptoms.

Question 13

What does the recovery trajectory look like for an athlete with an SRC versus a normal healthy adult?

Answer 13

Athletes with SRCs typically recover within 24 days, with recovery influenced by factors such as injury severity, age, concussion history, and adherence to rehabilitation protocols. Adolescents may take longer than adults to recover due to ongoing brain development and higher activity levels. Normal healthy adults, particularly those outside of athletic settings, usually recover within 14 days. Persistent symptoms beyond these timelines can lead to post-concussion syndrome, characterized by prolonged cognitive, physical, and emotional disturbances (McCrory et al., 2017; McAllister et al., 2023). For example, a high school athlete who sustains an SRC may take longer to recover compared to an adult who experiences a concussion in a non-sports setting, due to differences in brain development, functional demands, and pressure to return to play.

Question 14

Are there neuroprotective effects for playing sports?

Answer 14

Engaging in sports may have neuroprotective effects by promoting cardiovascular fitness, which enhances brain health, cognitive function, and neurogenesis. Physical activity is associated with improved vascular health, reduced neuroinflammation, and better mood regulation. However, the risk of concussions must be managed to prevent potential long-term consequences such as chronic traumatic encephalopathy (CTE) (McKee et al., 2013). For instance, participating in non-contact sports or using proper protective equipment, adhering to safe playing techniques, and following graduated return-to-play protocols can help athletes reap the benefits of physical activity while minimizing the risk of concussions.

Question 15

How does being part of a varsity team and having superior cardiovascular fitness affect one’s response to sustaining a concussion and their prognosis?

Answer 15

• Being part of a varsity team and having superior cardiovascular fitness can positively influence an athlete’s response to sustaining a concussion and their prognosis. Superior cardiovascular fitness is linked to better cerebral blood flow and recovery from brain injury. Fit athletes often have better baseline cognitive functioning and quicker recovery times. Moreover, being part of a varsity team provides access to structured medical care, supportive team environments, and professional rehabilitation resources. These factors can facilitate adherence to concussion management protocols, resulting in a more effective and timely recovery. However, the increased pressure to return to play quickly must be carefully managed to avoid compromising long-term brain health.

Question 16

17. Under what circumstances does a concussion turn into PCS?

Answer 16

Post-concussion syndrome (PCS) occurs when concussion symptoms persist beyond the typical recovery period (14 days for adults, 30 days for children). Risk factors for PCS include young age, female sex, severe early symptoms, history of repetitive concussions, and comorbidities such as migraines and psychiatric disorders (Broshek et al., 2015). For instance, a young female athlete with a history of migraines who sustains a severe concussion may be at increased risk for developing PCS.

Young age:

Younger individuals, especially children and adolescents, are at higher risk for PCS.
Their brains are still developing, and they may be more vulnerable to the effects of a concussion.
Younger individuals also have a longer recovery time ahead of them, which can increase the risk of developing persistent symptoms.
Female sex:

Studies have shown that women are more likely to develop PCS compared to men.
This may be due to factors such as hormonal differences, smaller brain size, and differences in neck strength and musculature.
Severe early symptoms:

Individuals who experience more severe symptoms immediately following a concussion, such as prolonged loss of consciousness, amnesia, or severe headaches, are more likely to develop PCS.
The severity of the initial injury can be an indicator of the extent of the brain damage, which may contribute to the development of persistent symptoms.
History of repetitive concussions:

Individuals with a history of multiple concussions, such as athletes in contact sports, are at a higher risk of developing PCS.
Repeated brain injuries can lead to cumulative damage, making the brain more vulnerable to the effects of subsequent concussions.
Comorbidities:

Conditions like migraines and psychiatric disorders, such as anxiety or depression, can increase the risk of PCS.
These comorbidities can exacerbate the symptoms of a concussion and make recovery more challenging.
Individuals with these pre-existing conditions may have a harder time recovering from the effects of a concussion.

Question 17

18. Under what circumstances does a concussion turn into CTE?

Answer 17

Chronic traumatic encephalopathy (CTE) is associated with a history of repetitive head injuries. While not all individuals with repeated concussions develop CTE, those with multiple concussions, particularly in contact sports, are at increased risk. The exact pathophysiological mechanisms linking concussions to CTE are still under investigation (McKee et al., 2013; Asken et al., 2016). For example, a professional football player who sustains multiple concussions over the course of their career may be at increased risk for developing CTE later in life. Younger age and shorter timing between injuries and genetic predisposition are risk factors.

Question 18

19. Are concussions detectable through neuroimaging?

Answer 18

Concussions are challenging to detect through standard neuroimaging techniques like CT and MRI, as these methods often do not show the microscopic damage characteristic of concussions. Advanced imaging techniques, such as functional MRI (fMRI) and diffusion tensor imaging (DTI), may reveal subtle changes, but their routine use in concussion diagnosis is limited (Slobounov et al., 2012). For instance, a concussed athlete may have a normal CT scan, but an fMRI may show changes in brain activation patterns compared to their pre-injury baseline.

Question 19

21. What are risk factors for concussion? Mention age, sex, gender, education, history of injury, type of sport played, psychiatric comorbidity, etc.

Answer 19

• Risk factors for concussions include:
• Age: Youth are at higher risk.
• Sex: Females are more susceptible to PCS.
• History of injury: Previous concussions increase risk.
• Type of sport: Contact sports like hockey, soccer, and football have higher rates of concussions.
• Psychiatric comorbidity: Conditions like anxiety and depression can prolong recovery (Broshek et al., 2015).
• For instance, a young female hockey player with a history of concussions and anxiety may be at increased risk for sustaining a concussion and experiencing prolonged symptoms.

Question 19

20. Are concussions detectable through EEG, FNIRS, TCD?

Answer 19

Electroencephalography (EEG):

EEG can detect changes in brain electrical activity following a concussion.
Concussions may be associated with changes in the power spectrum, including increased delta and theta power, and decreased alpha and beta power.
Alterations in event-related potentials (ERPs), such as reduced amplitudes and prolonged latencies, have also been observed in individuals with concussions.
Functional Near-Infrared Spectroscopy (fNIRS):

fNIRS is a non-invasive optical imaging technique that can measure changes in oxygenated and deoxygenated hemoglobin concentrations in the brain.
Concussions may result in altered patterns of brain activation and changes in cerebral blood flow and oxygenation, which can be detected using fNIRS.
Studies have reported decreased oxygenation and blood flow in the prefrontal cortex and other brain regions following a concussion.
Transcranial Doppler (TCD) Ultrasound:

TCD can measure changes in cerebral blood flow velocities, which may be affected by concussions.
Concussions have been associated with decreased cerebral blood flow velocities, particularly in the middle cerebral artery, as well as increased pulsatility index, which reflects changes in cerebrovascular resistance.

Question 20

22. What are the most common ocular and vestibular dysfunctions following an SRC?

Answer 20

Common ocular dysfunctions include difficulties with eye movements and visual processing, while vestibular dysfunctions involve balance problems and dizziness. These impairments can contribute to prolonged symptoms and delayed recovery (Mucha et al., 2014). For example, an athlete who sustains a concussion may experience blurred vision, difficulty tracking moving objects, and balance issues that persist beyond the initial recovery period.

Question 21

23. What are the most common psychological impairments following an SRC?

Answer 21

Psychological impairments following SRC include increased anxiety, depression, irritability, and emotional instability. Providing psychological support and interventions like cognitive-behavioral therapy (CBT) can help manage these symptoms (Broshek et al., 2015). For instance, an athlete who experiences persistent anxiety and depression following a concussion may benefit from CBT to help them cope with their symptoms and improve their overall well-being.

Question 22

24. What are the most common cognitive impairments following an SRC?

Answer 22

Cognitive impairments following SRC include difficulties with attention, memory, processing speed, and executive function. Neurocognitive testing, such as ImPACT™, helps assess these impairments and guide management (Allen & Gfeller, 2011). For example, an athlete who sustains a concussion may have difficulty concentrating, remembering new information, and making decisions, which can be identified through neurocognitive testing and addressed through targeted cognitive rehabilitation exercises.

Question 23

25. Describe the acute, subacute, postacute, and chronic stages of SRC.

Answer 23

• Acute stage: Immediate phase post-injury, characterized by symptoms such as headache, dizziness, and cognitive impairment.
• Subacute stage: Symptoms may persist but begin to stabilize. Initial rest followed by graded physical activity is recommended.
• Postacute stage: Symptoms persist beyond the typical recovery period, and interventions focus on rehabilitation and managing PCS.
• Chronic stage: Long-term symptoms and complications, potentially including CTE in cases of repeated concussions (McCrory et al., 2017).
  For instance, an athlete in the acute stage of a concussion may experience severe headache and confusion, while an athlete in the subacute stage may have milder symptoms and begin light physical activity. An athlete in the postacute stage may require more extensive rehabilitation to manage persistent symptoms, while an athlete in the chronic stage may develop long-term complications like CTE.

Question 24

26. Describe the key takeaway from the newest Concussion Consensus Statement in Amsterdam.

Answer 24

• The key takeaway from the 6th International Consensus Statement on Concussion in Sport held in Amsterdam in October 2022 is that there is no perfect diagnostic test or biomarker for acute concussion, and diagnosis remains a clinical judgment.
• The consensus statement emphasizes the importance of a multimodal assessment approach, including clinical history, symptom evaluation, cognitive assessment, and neurological examination.
• It also highlights the need for a standardized approach to diagnosis, management, and return-to-play decisions, while acknowledging the complex nature of concussion and the ongoing challenges in its assessment and treatment
• It emphasizes early, light-intensity physical activity within 24-48 hours post-concussion and the use of sub-symptom threshold aerobic exercise within 2-10 days post-injury. This approach is recommended to reduce persistent symptoms and promote recovery.
  For example, an athlete who sustains a concussion would be advised to engage in light physical activity, such as walking or stationary cycling, within the first few days of the injury, and progress to sub-symptom threshold aerobic exercise within the first two weeks to promote recovery and reduce the risk of persistent symptoms.

Question 25

Who is more at risk, who underreports, and who have more prolonged concussion recovery between males and female

Answer 25

Risk of Concussions:

Females are generally at a higher risk of sustaining a concussion compared to males, especially in sports.
Studies have shown that female athletes have a 1.5 to 2 times greater risk of concussion than their male counterparts playing the same sports.

Anatomical and Physiological Differences:

Females typically have smaller and weaker neck muscles compared to males, which may result in greater head and neck acceleration during an impact, leading to more brain movement and a higher risk of concussion.
Females also have a smaller average brain size, which may make them more susceptible to the effects of brain trauma.
Hormonal Differences:

Hormonal fluctuations throughout the menstrual cycle in females may affect the brain’s vulnerability to concussion and its ability to recover from injury.
Estrogen, for example, has been shown to have neuroprotective effects, and changes in its levels may influence the risk and severity of concussions.
Biomechanical Factors:

Females tend to have different biomechanical characteristics, such as center of gravity, muscle activation patterns, and landing mechanics, which may contribute to a higher risk of head impacts and concussions, particularly in sports.
Reporting and Diagnosis:

Females may be more likely to report concussion symptoms, which can lead to a higher rate of diagnosis compared to males, who may be more reluctant to report their symptoms.
Sport and Activity Participation:

The types of sports and activities that females participate in may also contribute to their higher concussion risk. For example, sports like soccer and basketball, which involve more head-to-head or head-to-ground contact, are popular among female athletes.
Previous Concussion History:

Females with a history of previous concussions may be at an even higher risk of sustaining subsequent concussions, as the brain may be more vulnerable to further injury.

Underreporting of Concussions:

Males are more likely to underreport their concussion symptoms and continue playing or engaging in physical activity despite a suspected concussion.
This is often due to cultural norms, perceived toughness, and a desire to avoid being removed from play.
Prolonged Concussion Recovery:

Females tend to have a longer recovery time and experience more persistent symptoms following a concussion compared to males.
This may be due to a combination of factors, including hormonal differences, smaller brain size, and differences in neck strength and musculature.

Question 26

Use the literature cited in your thesis to elucidate the role of exercise in concussion symptom resolution:

Answer 26

• Instead, relative rest, which involves engaging in activities of daily living and limiting screen time, is recommended for the first 1-2 days following the injury (Leddy et al., 2023).
• Convergent evidence indicates that carefully controlled exercise may be beneficial in promoting recovery and shortening the duration of symptoms associated with SRC (Kurowski et al., 2017; Leddy et al., 2013; Maerlender et al., 2015; Schneider et al., 2017).
• For example, Maerlender et al. (2015) investigated the effects of immediate (median = 2 days) post-SRC exercise compared to a no-exercise control group in collegiate athletes. The study found that moderate physical activity did not significantly affect recovery time, and SRC symptoms following exercise were only present initially and dissipated over subsequent exercise sessions. These findings suggest that moderate physical activity is safe during the initial phase of SRC recovery
• Kurowski et al. (2017) investigated the effects of a structured aerobic exercise program versus full-body stretching on recovery time and symptom burden in adolescents with mTBI experiencing persistent symptoms for 4-16 weeks. The aerobic exercise group demonstrated greater improvement in the Post-Concussion Symptom Inventory (PCSI) total score and the emotional and fatigue subscales compared to the stretching group, suggesting that structured aerobic exercise may be an effective treatment for adolescents with persistent post-mTBI symptoms.
• Leddy et al. (2013) compared fMRI activation patterns, exercise capacity, and symptoms in PCS patients and healthy controls at baseline and after approximately 12 weeks, during which they received either exercise treatment or placebo stretching. Exercise PCS patients showed similar fMRI activation to healthy controls after 12 weeks, whereas placebo-stretching PCS patients had significantly decreased resting-state cortical and subcortical activity.

As well, Schneider et al.’s (2017) review of rest, treatment and rehabilitation techniques following SRC, reported that athletes in submaximal exercise groups reported fewer symptoms, exhibited shorter recovery times to baseline cognitive and balance scores, and demonstrated more efficient fMRI activation patterns compared to matched controls.

Question 27

Use the literature cited in your thesis to describe current research on antisaccades in an SRC population

Answer 27

• To the best of my knowledge, only three studies to date have investigated antisaccades in healthy young adults with SRC.
• Johnson et al. (2015a; 2015b) examined behavioural data and fMRI measures of antisaccades in athletes with an SRC and age- and sex-matched controls at two distinct time points: initially (<7 days post-injury) and at follow-up (30 days post-injury). The concussed group exhibited longer antisaccade RTs and more directional errors at both assessments, with fMRI data showing hypo- and hyperactivity patterns across cortical and subcortical structures in the concussed group; however, follow-up fMRI findings did not significantly differ between groups.
• More recently, Webb et al. (2018) investigated athletes with an SRC and age- and sex-matched controls at 2-6 days post-injury (initial assessment) and 14-20 days after the initial assessment (follow-up assessment). At the initial assessment, the SRC group exhibited longer antisaccade RTs and more directional errors, whereas follow-up RTs were comparable between groups. Notably, however, the SRC group demonstrated more directional errors at the follow-up assessment even though they had been medically cleared for RTS. These findings suggest that antisaccades are sensitive to executive-related concussive deficits in both early and later stages of recovery. Moreover, the increased frequency of antisaccade directional errors reflects a failure to engage the high-level EF task-set required to evoke non-standard responses (Everling & Johnston, 2013). Although often considered purely inhibitory control tasks (Munoz & Everling, 2004), antisaccades also require working memory and cognitive flexibility to maintain the goal of performing an antisaccade instead of a prosaccade. Only deliberate practice can reduce antisaccade directional errors, as they represent a nonstandard task-set (Dyckman & McDowell, 2005). Thus, the increased directional errors in the SRC group, despite RTS clearance, suggest an oculomotor EF deficit (Everling & Johnston, 2013).
• Ayala et al. (2020) investigated whether oculomotor deficits associated with SRC result from impaired EF planning mechanisms or task-based increases in SRC symptomology. The authors employed SCAT-5, antisaccade performance, and pupillometry metrics in individuals with SRC during the early (≤12 days post-SRC) and later (14-30 days post-SRC) stages of recovery. The early assessment revealed longer RTs, more directional error, and larger task-evoked pupil dilations (TEPD) in the SRC group compared to controls. At the later stage of assessment, RTs did not significantly differ between groups; however, the SRC group continued to demonstrate increased directional errors and TEPDs. Notably, Ayala and Heath observed that SCAT-5 symptom scores at early and later assessments did not vary from pre- to post-oculomotor assessments; that is, oculomotor assessment did not result in an increase in task-based symptom burden. Taken as a whole, these studies highlight the potential of the antisaccade to serve as a valuable tool for detecting SRC EF deficits and monitoring recovery and safe RTS.

Question 28

Describe the three kinematic responses to SRC

Answer 28

Centroidal contact: Linear acceleration without head rotation, causing minimal brain motion/deformation.
Non-centroidal contact without linear acceleration: Rotational acceleration, leading to diffuse axonal injury.
Non-centroidal contact with linear acceleration: Both linear and rotational acceleration, causing microscopic shearing and stretching of brain structures.

Question 29

Compare and contrast the IMPACT with SCAT-5

Answer 29

• The IMPACT (Immediate Post-Concussion Assessment and Cognitive Testing) assessment and SCAT (Sport Concussion Assessment Tool) are both comprehensive concussion assessment batteries, but they have some key differences:
• 1. Computerized vs. Paper-and-Pencil:
• IMPACT is a computerized, neurocognitive test battery.
• SCAT is a paper-and-pencil assessment, with some components that can be administered digitally.
• 2. Cognitive Assessment:
• IMPACT focuses more on detailed, objective neurocognitive testing, including measures of verbal memory, visual memory, processing speed, and reaction time.
• SCAT includes more general cognitive screening tests, such as the Maddocks questions and the Standardized Assessment of Concussion (SAC).
• 3. Balance Assessment:
• IMPACT includes a standardized balance assessment, such as the Balance Error Scoring System (BESS).
• SCAT also includes a balance assessment, but it may be less comprehensive than the IMPACT balance evaluation.
• 4. Symptom Evaluation:
• Both IMPACT and SCAT include a symptom evaluation, but they may use different symptom checklists and rating scales.
• 5. Clinician Involvement:
• IMPACT is primarily a computerized assessment, with clinician involvement in interpreting the results.
• SCAT involves more direct clinician observation and assessment, with a more comprehensive clinical interview.
• 6. Normative Data
• IMPACT has a larger database of normative data, as it is more widely used, particularly in the United States.
• SCAT may have more limited normative data, as it is used more globally.
• 7. Administration Time:
• IMPACT typically takes 20-30 minutes to administer.
• SCAT can take 15-30 minutes, depending on the clinical interview and additional assessments.

In summary, IMPACT is more focused on objective, computerized neurocognitive testing, while SCAT provides a more comprehensive, clinician-administered assessment of various concussion-related domains. Both tools are valuable for the evaluation and management of sports-related concussions, and clinicians may use a combination of the two depending on the specific needs and resources of their sports medicine progra

Question 30

Do people with acute concussions have higher DLPFC and ACC functional activation and connectivity as a result of a compensatory mechanism to engage in EF tasks? Of do they have lower activation and connectivity because of lower CBF

Answer 30

• Research on individuals with acute concussions (typically within the first 2 weeks post-injury) has consistently demonstrated reduced activation and functional connectivity within the dorsolateral prefrontal cortex (DLPFC) and anterior cingulate cortex (ACC) during the performance of executive function (EF) tasks, when compared to healthy control subjects.
• This phenomenon is thought to be a direct consequence of the concussion-related reduction in cerebral blood flow (CBF), which occurs in the acute post-injury period.
• The acute concussive event triggers a complex neurometabolic cascade, which includes transient alterations in ion homeostasis, neurotransmitter release, and energy substrate availability.
• The decreased CBF impairs the ability of these critical brain regions to adequately support the increased metabolic demands required for successful EF task performance.
• This reduction in activation and connectivity within the DLPFC and ACC likely reflects a temporary disruption in the normal neurovascular coupling and metabolic processes that underlie cognitive functioning.
• Over time, as the neurometabolic cascade resolves and the brain’s compensatory mechanisms become more effective, the DLPFC and ACC may exhibit increased activation and connectivity during EF tasks as part of the recovery process.