Sport Concussion Assessment Tool, version 6 — a stepwise sideline protocol for evaluating suspected concussion in athletes aged 13+, from red-flag screening to the final return-to-play decision
Before a single question of the SCAT6 is asked, the on-field assessor must rule out a catastrophic or unstable injury. The SCAT6 explicitly begins with an emergency-triage step: a checklist of red-flag signs and symptoms that, if present, override everything else and mandate activation of emergency action plans and transport to the nearest emergency department. Only once these are cleared does gentle removal from the field and cervical spine precautions allow the assessor to proceed to the observable-signs checklist and, later, the symptom and cognitive testing.
The SCAT6 red-flag list is deliberately simple and memorable so it can be applied under sideline pressure by non-physician first responders:
• Neck pain or tenderness • Double vision • Weakness or tingling/burning in the arms or legs • Severe or increasing headache • Seizure or convulsion • Loss of consciousness (any duration) • Deteriorating conscious state • Vomiting • Increasingly restless, agitated, or combative
Any single item present means the athlete is treated as having a potential catastrophic head or cervical spine injury. The correct action is not to continue the SCAT6 — it is to activate the venue’s emergency action plan, immobilize the cervical spine if trauma is suspected, and arrange emergency transport. The red-flag step exists precisely because a screening tool designed for concussion must never be allowed to delay recognition of a bleed, fracture, or unstable spinal injury.
The red-flag checklist is a hard gate, not a scoring item. A single positive red flag overrides every other SCAT6 finding — including a subsequently "normal" symptom score or cognitive test — and mandates emergency transport regardless of how the athlete looks minutes later.
While red flags are being ruled out, the assessor scores the Glasgow Coma Scale (GCS): best eye-opening response (1–4), best verbal response (1–5), and best motor response (1–6), summed to a maximum of 15. Any GCS below 15, or any deterioration on repeat scoring, is itself an indication for emergency management.
Alongside GCS, the assessor watches for observable signs that suggest concussion even before the athlete can answer questions: lying motionless on the ground, slow to get up, disorientation or confusion, blank or vacant look, balance or gait difficulties, facial injury, or a visible impact seizure/tonic posturing. Observable signs do not require the athlete’s cooperation and can be scored by a teammate, coach, or spectator with basic training — making them one of the most sensitive early triggers to stop play and begin assessment.
Because helmet-to-helmet, head-to-ground, and high-velocity collision mechanisms that cause concussion can simultaneously injure the cervical spine, SCAT6 assessment protocol requires cervical spine precautions to be maintained until an unstable neck injury has been actively excluded. This means: minimizing movement of the head and neck, maintaining spinal alignment if the athlete must be moved, and only proceeding with active range-of-motion neck screening (covered later in the balance/neurological stage) once gross instability has been ruled out by a qualified provider.
This stage-1 gate reflects a core philosophy of SCAT6: it is a concussion-specific tool nested inside a broader emergency medical framework, and it is only valid to administer once life-threatening and spine-threatening injuries have been excluded.
Once red flags are excluded, the athlete completes the SCAT6 symptom checklist: 22 physical, cognitive, sleep, and emotional symptoms, each self-rated on a 0–6 severity scale (0 = none, 6 = severe). The checklist yields two numbers that anchor every later stage of assessment and every follow-up visit: the symptom number (how many of the 22 are present, 0–22) and the symptom severity score (the sum of all 22 ratings, 0–132).
The checklist groups naturally into four symptom clusters, though SCAT6 presents them as a single flat list to avoid biasing responses:
Somatic/physical: headache, "pressure in head," neck pain, nausea or vomiting, dizziness, blurred vision, balance problems, sensitivity to light, sensitivity to noise
Cognitive: feeling slowed down, feeling "in a fog," difficulty concentrating, difficulty remembering
Sleep/arousal: fatigue or low energy, drowsiness, trouble falling asleep (if applicable that night)
Emotional: more emotional than usual, irritability, sadness, nervousness or anxiety
General: a nonspecific "don’t feel right" item that captures symptoms not otherwise listed
Each item is rated independently by the athlete, ideally without coaching staff prompting specific answers, since self-report symptom scales are known to be influenced by suggestion and by the athlete’s motivation to report (or under-report) how they feel.
Two distinct scores are derived from the same 22 ratings:
Symptom number = count of items rated ≥1 (range 0–22). This answers "how many different things feel wrong."
Symptom severity score = sum of all 22 ratings (range 0–132). This answers "how bad, in total, does the athlete feel." A high symptom number with low individual severities (e.g., 15 symptoms all rated 1) produces a moderate severity score, while a low symptom number with a few severe items (e.g., 3 symptoms rated 6) can still produce a clinically significant severity score. Both numbers matter, and both are far more informative when compared against the athlete’s own pre-season baseline than against a fixed population cutoff, because normal, uninjured athletes commonly endorse a handful of low-grade symptoms (poor sleep, mild fatigue) at baseline.
Because symptom scores are dynamic, SCAT6 explicitly recommends serial administration: at the time of injury, then again at intervals over the following hours and days, rather than treating one score as a final answer. A symptom score that is elevated immediately after injury but resolving over 30–60 minutes still represents a suspected concussion at the time of injury and should be managed as such — the SCAT6 is not intended to "clear" an athlete based on rapid symptom resolution alone, since symptoms are known to fluctuate and can be masked by adrenaline in the minutes after an on-field collision.
The Standardized Assessment of Concussion (SAC) forms the cognitive core of the SCAT6. It is a brief, standardized battery covering four domains: sport-specific orientation, immediate (working) memory across repeated trials, concentration, and — later, in the balance stage — delayed recall of the same word list. Because concussion frequently impairs attention, encoding, and processing speed before it impairs anything else observable, the SAC is often the most sensitive component of the entire sideline exam.
Standard orientation questions (What is the date? Where are you?) are unreliable in a sport setting because athletes are frequently unsure of the exact date or venue name even when uninjured. The modified Maddocks questions instead ask sport-specific context the athlete should reliably know: What venue are we at today? Which half/period is it now? Who scored last in this match? What team did you play last week/game? Did your team win the last game? Correct, immediate answers to these questions are far more specific to acute cognitive impairment than generic orientation items, and rapid, confident, correct responses reduce false positives in a noisy sideline environment.
The examiner reads a list of 5 or 10 unrelated single-syllable words at a fixed rate (about one word per second) and asks the athlete to recall as many as possible, in any order, immediately afterward. The same list is presented again for two further trials (3 trials total), and the athlete’s score is the sum of correctly recalled words across all three trials (maximum 15 for a 5-word list, 30 for a 10-word list, though SAC scoring normalizes this into the 15-point immediate memory component).
Repeating the same list across trials tests learning — an uninjured athlete typically recalls more words on trial 2 and 3 than trial 1 as encoding strengthens with repetition. A concussed athlete often shows a flatter learning curve, plateauing early or even declining, reflecting impaired new-learning capacity rather than a simple attention lapse.
Concentration testing has two parts. First, digit strings of increasing length (starting at 3 digits, up to 6) are read aloud and the athlete must repeat them in reverse order — a working-memory task that requires holding and manipulating information rather than simple rote repetition. Second, the athlete recites the months of the year in reverse order (December, November, October…), a well-learned overlearned sequence that becomes surprisingly difficult to reverse under cognitive load, testing sequencing and mental flexibility.
Together, orientation (5 points), immediate memory (15 points), and concentration (5 points) sum with the later delayed-recall component (5 points) to produce the SAC total score out of 30. A lower-than-baseline SAC score, or a score meaningfully below normative expectations, supports — but on its own never confirms — a diagnosis of concussion; SAC performance is also affected by fatigue, prior concussion history, age, and even by test anxiety on the sideline.
Concussion frequently disrupts postural control through impaired integration of visual, vestibular, and proprioceptive input, even when the athlete feels subjectively steady. The modified Balance Error Scoring System (mBESS) quantifies this objectively across three stances, and is combined with a cervical spine screen, a coordination/gait check, and — completing the SAC — delayed recall of the word list learned in stage 3.
The athlete stands on a firm surface (the modified version omits the foam-pad condition used in the full BESS, though some protocols still include it) with hands on hips and eyes closed, and holds each of three stances for 20 seconds while the examiner tallies errors:
1. Double-leg stance: feet together, side by side 2. Single-leg stance: standing on the non-dominant foot, other leg held in ~20–30° hip flexion 3. Tandem stance: non-dominant foot directly behind the dominant foot, heel-to-toe
Countable errors include: opening the eyes, lifting hands off hips, stepping/stumbling/falling, moving the hip into more than 30° flexion or abduction, lifting the forefoot or heel, or remaining out of the proper testing position for more than 5 seconds. Each stance is capped at a maximum of 10 errors even if the athlete cannot maintain the position at all, so the total mBESS error score across all three 20-second trials ranges from 0 (perfect) to 30 (maximum errors).
With any gross instability already excluded in stage 1, the examiner now performs an active cervical spine screen: range of motion in flexion, extension, rotation, and lateral flexion, plus palpation for midline tenderness. Pain, restricted range, or point tenderness prompts referral for imaging and formal cervical spine assessment rather than continuing the concussion-specific exam.
Coordination is assessed with a finger-to-nose task and observation of gait — walking in a straight line, turning, and returning — watching for ataxia, veering, or asymmetry that would suggest a focal neurological deficit requiring more urgent evaluation than concussion alone.
Roughly 5 minutes after the immediate memory trials in stage 3 (filled by the balance and cervical screening in the interim), the athlete is asked — without warning beforehand — to recall as many words from the original list as possible. This delayed recall score (0–5, or 0–10 depending on list length, normalized to 5 points) is the fourth and final SAC component. Because it is unprompted and unrehearsed, delayed recall is particularly sensitive to concussion-related deficits in memory consolidation, and a disproportionate drop-off between immediate and delayed recall is a recognized red flag for cognitive impairment even when the immediate trials looked reasonable.
The single most important instruction in the entire SCAT6 document is not a scoring rule — it is a principle. SCAT6 is explicitly designed as a multi-modal screening aid that supports, but never replaces, clinical judgment. No combination of "normal" red-flag screen, symptom score, SAC score, and mBESS score is sufficient on its own to rule out a concussion, and the tool’s authors are emphatic that any suspected concussion means immediate removal from play.
A "normal" or baseline-equivalent SCAT6 score performed on the sideline in the minutes after a suspected head impact does not clear an athlete to return to play. This is because concussion signs and symptoms can be delayed by minutes to hours, adrenaline can mask symptoms acutely, and the SCAT6 itself has documented practice effects and limited sensitivity in some individuals (discussed below). Any athlete suspected of having sustained a concussion — based on mechanism of injury, observable signs, symptom report, or examiner concern — must be removed from play for that session, regardless of test scores, and should not be allowed to return to play the same day.
"If in doubt, sit them out" is deliberately framed as a floor, not a suggestion. The clinical cost of one missed concussion — second-impact risk, prolonged recovery from continued play, or catastrophic injury — is judged to far outweigh the cost of one unnecessary sideline removal. SCAT6 scores inform this decision; they do not override it.
The tool’s own developers list explicit limitations that every user must understand:
• Practice effects: repeated administration of the same word lists and orientation questions across a season can artificially inflate scores as athletes learn the test itself, not because they have recovered — alternate word-list forms are recommended for serial testing • Effort dependence: SAC and mBESS both require the athlete’s genuine effort; sub-maximal effort (intentional or due to fear of removal) lowers apparent scores or can mask deficits • Insensitivity in some individuals: athletes with high baseline cognitive or physical reserve may score in a "normal" range despite genuine concussion, especially on brief screening measures • Age restrictions: SCAT6 is validated for athletes 13 years and older; a separate Child SCAT6 exists for ages 8–12, using age-appropriate symptom lists and cognitive tasks and should not be substituted with the adult version • Not diagnostic in isolation: no SCAT6 score or component, alone, establishes or excludes a diagnosis of concussion — diagnosis is a clinical determination integrating history, mechanism, exam, and course over time
Because normative "cutoff" scores vary enormously between individuals — by age, sex, prior concussion history, learning differences, and even by sport — SCAT6 is most powerful when the post-injury score is compared to that specific athlete’s own pre-season baseline SCAT6, administered when healthy. A drop of several points in SAC, an increase in symptom number/severity, or new mBESS errors relative to a documented individual baseline is far more meaningful than comparison to a population average. Baseline testing is especially recommended for athletes in collision/contact sports and for those with a prior concussion history, where individual variability is highest and the stakes of missing a subtle change are greatest.
SCAT6 is explicitly validated and recommended for use only within the first 72 hours after a suspected concussion — it is an acute assessment tool. Beyond that window, its sensitivity to ongoing impairment declines and different, more specialized instruments are recommended for monitoring recovery and guiding graduated return to sport and return to learn: tools such as the Sport Concussion Office Assessment Tool (SCOAT6) for clinic-based follow-up, formal neuropsychological testing, vestibular-ocular motor screening, and graded exertion protocols. Treating SCAT6 as a one-time verdict rather than the first data point in a longer, individualized recovery pathway is one of the most common and most consequential misuses of the tool.