Residency · Residency · Physical Medicine Rehabilitation

Concussion Assessment and Return-to-Play Protocols

Definition and Pathophysiology

Definition

A concussion is a traumatic brain injury induced by biomechanical forces that results in a complex pathophysiological process affecting the brain. Does NOT require loss of consciousness (LOC occurs in <10% of concussions). Functional disturbance rather than a structural injury; standard neuroimaging is typically normal. Also termed "mild traumatic brain injury" (mTBI), though the terms are not perfectly synonymous.

Biomechanics

Direct blow to the head, face, neck, or body with impulsive force transmitted to the head. Linear acceleration causes focal injury; rotational acceleration causes diffuse shear strain. Rotational forces are most important for producing concussion symptoms. No minimum force threshold exists; individual vulnerability varies significantly.

Neurometabolic Cascade

Mechanoporation of neuronal membranes causes indiscriminate ion flux. Massive potassium efflux and glutamate release cause widespread depolarization. Sodium-potassium ATPase pumps work overtime to restore ionic balance, creating an energy crisis. Increased glucose demand coupled with decreased cerebral blood flow.

Calcium influx leads to mitochondrial dysfunction and oxidative stress. Axonal injury from cytoskeletal disruption. Neuroinflammatory response with microglial activation. Recovery timeline: metabolic normalization typically takes 7-10 days but can extend weeks.

<image>Diagram of the neurometabolic cascade following concussion showing sequential steps from mechanical force causing membrane disruption, to ionic flux and glutamate release, energy crisis with increased glucose demand and decreased cerebral blood flow, mitochondrial dysfunction, and neuroinflammation, with typical recovery timeline</image>

Sideline and Acute Assessment

Immediate Assessment

Remove from play for any suspected concussion. ABCs and cervical spine precautions if indicated. Assessment for red flags requiring emergency department transfer: Deteriorating consciousness (GCS decline). Increasing headache severity. Seizure. Repeated vomiting. Focal neurological deficit. Signs of skull fracture (Battle sign, raccoon eyes, CSF rhinorrhea/otorrhea). Neck pain or cervical spine tenderness.

SCAT6 (Sport Concussion Assessment Tool, 6th Edition)

Standardized sideline assessment tool endorsed by the Concussion in Sport Group (CISG). Components: Symptom checklist (22 symptoms rated 0-6 for severity). Physical signs and neurological screening.

Cognitive assessment: orientation, immediate memory (10-word list), concentration (digits backward, months in reverse). Cervical spine and balance examination. Delayed recall (5-minute interval). Modified Balance Error Scoring System (mBESS).

Baseline testing is recommended but not required for interpretation. Cannot make a concussion diagnosis; used as a structured assessment tool.

Vestibular/Oculomotor Screening (VOMS)

Assesses vestibular and oculomotor function. Components: smooth pursuits, horizontal and vertical saccades, convergence, VOR (horizontal, vertical), visual motion sensitivity. Each item assessed for symptom provocation. Near point of convergence (NPC) >5 cm is abnormal. Positive VOMS findings predict prolonged recovery.

King-Devick Test

Rapid-number naming test assessing saccadic eye movements, attention, and processing speed. Quick sideline tool (2-3 minutes). Time increase from baseline suggests concussion. Validated as a sideline screening adjunct.

Clinic-Based Evaluation

Comprehensive History

Mechanism of injury and acute symptoms. Symptom timeline and trajectory (improving, stable, worsening). Concussion history (number, recovery duration, threshold for subsequent injury). Pre-existing conditions: migraine, ADHD, learning disability, mood disorders, sleep problems. Medications and substance use. Academic and occupational demands.

Symptom Assessment

Post-Concussion Symptom Scale (PCSS): 22 symptoms rated 0-6. Symptom clusters: Physical/somatic: headache, nausea, balance problems, dizziness, visual problems, fatigue, light/noise sensitivity. Cognitive: feeling foggy, difficulty concentrating, difficulty remembering, feeling slowed down.

Emotional: irritability, sadness, nervousness, more emotional than usual. Sleep: drowsiness, sleeping more or less than usual, difficulty falling asleep.

Physical Examination

Neurological examination (cranial nerves, motor, sensory, coordination, reflexes). Cervical spine assessment (ROM, palpation, spurling, upper cervical ligament testing). Vestibular examination (VOMS, head impulse test, Dix-Hallpike, BPPV assessment). Oculomotor assessment (convergence, accommodation, saccades, smooth pursuits). Balance testing (modified BESS, Romberg, tandem gait). Cognitive screening.

Neuropsychological Testing

Computerized tools: ImPACT, CogSport/CogState, CNS Vital Signs. Assess processing speed, reaction time, memory, attention. Most useful when baseline testing is available for comparison. Controversy regarding reliability of baseline testing and whether it changes management. Formal neuropsychological evaluation reserved for persistent symptoms or complex cases.

Imaging Indications

Standard CT and MRI are typically normal in concussion (by definition). CT indicated acutely per Canadian CT Head Rule or NEXUS criteria (LOC, amnesia, focal deficits, vomiting, coagulopathy, age >60). MRI indicated for focal neurological findings, prolonged symptoms, or concern for structural injury. Advanced neuroimaging (DTI, fMRI, SWI) remains primarily research tools.

<image>Flowchart of the graduated return-to-play protocol showing six stages from symptom-limited activity through light aerobic exercise, sport-specific exercise, non-contact training drills, full-contact practice, and return to competition, with minimum 24-hour intervals between stages and criteria for stage advancement</image>

Return-to-Play Protocol

Graduated Return-to-Play (GRTP) -- 2023 Consensus

Must be symptom-free at rest before beginning (or stable at baseline for those with pre-existing symptoms). Minimum 24-48 hours between stages; most athletes complete the protocol in 7-10 days. If symptoms recur at any stage, return to the previous asymptomatic stage for 24 hours.

Medical Clearance

Required before Stage 5 (full-contact practice). Must be provided by a physician or designated healthcare provider experienced in concussion management. Consider neuropsychological testing, especially if available baseline.

Special Considerations for Pediatric Athletes

Children and adolescents have longer recovery times than adults (median 4 weeks vs. 10-14 days). More conservative return-to-play timelines recommended. Must not return to full-contact practice on the same day as injury (universal consensus). Return-to-learn should be prioritized alongside return-to-play. No same-day return to play for any suspected concussion (consensus statement).

Return-to-Learn Protocol

Graduated Return to School

Stage 1: daily activities at home (limited screen time, reading). Stage 2: school activities at home (homework, reading, online classes). Stage 3: partial school attendance (increased tolerance, gradual academic load). Stage 4: full school attendance with accommodations (extended test time, reduced workload).

Stage 5: full school attendance without accommodations. Academic accommodations may include: rest breaks, reduced homework, extended deadlines, quiet testing environment, excusal from standardized testing.

Emerging Biomarkers

Blood-Based Biomarkers

GFAP (glial fibrillary acidic protein) and UCH-L1 (ubiquitin C-terminal hydrolase-L1): FDA-cleared for ruling out intracranial lesions on CT (Banyan BTI). Neurofilament light chain (NfL): marker of axonal injury, elevated in concussion. S100B: glial marker, used in European guidelines to reduce unnecessary CT scans. Biomarkers may help with diagnosis, prognosis, and return-to-play decisions in the future.

Risk Factors for Prolonged Recovery

History of prior concussion (especially with prolonged recovery). Female sex. Younger age (pediatric and adolescent). Pre-existing migraine history.

Pre-existing mood disorder (depression, anxiety). ADHD or learning disability. High initial symptom burden. Vestibular and oculomotor abnormalities on initial assessment. Loss of consciousness or amnesia (modest association).

Clinical Pearls

Loss of consciousness is NOT required for concussion diagnosis and occurs in less than 10% of cases. "When in doubt, sit them out" remains the cardinal rule for sideline management. Most concussions resolve within 10-14 days in adults and 4 weeks in children; symptoms beyond this warrant further evaluation. Brief cognitive and physical rest (24-48 hours) followed by gradual return to sub-symptom-threshold activity is now recommended over prolonged "cocoon" rest.

Cervicogenic contributions to persistent symptoms are frequently overlooked; always assess the cervical spine. Vestibular rehabilitation is one of the most effective treatments for persistent vestibular-type symptoms. Each concussion should be managed individually; there is no magic number of concussions that mandates retirement. Pre-existing conditions (migraine, anxiety, ADHD) prolong recovery and must be managed concurrently.

References

• Patricios JS, et al. Consensus Statement on Concussion in Sport: The 6th International Conference on Concussion in Sport. Br J Sports Med. 2023;57(11):695-711.
• McCrory P, et al. Consensus Statement on Concussion in Sport: The 5th International Conference on Concussion in Sport. Br J Sports Med. 2017;51(11):838-847.
• Mucha A, et al. A Brief Vestibular/Ocular Motor Screening (VOMS) Assessment to Evaluate Concussions. Am J Sports Med. 2014;42(10):2479-2486.
• Leddy JJ, et al. Early Subthreshold Aerobic Exercise for Sport-Related Concussion: A Randomized Clinical Trial. JAMA Pediatr. 2019;173(4):319-325.
• Harmon KG, et al. American Medical Society for Sports Medicine Position Statement: Concussion in Sport. Br J Sports Med. 2013;47(1):15-26.

Read this lecture as Markdown