Purpose
The SCAT3 evaluates injured athletes aged 13+ for concussions.
Link to Instrument
Acronym
SCAT3
Primary Image
Sport Concussion Assessment Tool-3
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Populations
Key Descriptions
- Symptom Evaluation:
1) Patient rated scale of current symptoms (22 symptoms possible)
2) Completed in resting state 10 minutes post exercise
3) Item-level scores range from 0-6, determined by symptom level
4) Item scores are summed: minimum = 0; maximum = 132 - Standardized Assessment of Concussion (SAC):
1) A cognitive screen assessing orientation, immediate memory and delayed recall, and concentration
2) Item scores are summed
3) Score range, 0-30: higher scores indicate better performance - Modified Balance Error Scoring System (mBESS):
1) Assesses postural stability errors while in 3 positions on a hard surface for 20 seconds each: double leg stance, single leg stance with non-dominant foot, and tandem stance with non-dominant foot at the back
2) 10 errors maximum per trial
3) Score range, 0-30 errors
4) Scores are summarized, repeated, and compared to baseline or normative data
5) Administration instructions are listed on the SCAT-3 form - If younger than 13, the Child SCAT3 may be used.
- The SCAT3 consists of:
1) Symptom Evaluation
2) Standardized Assessment of Concussion (SAC)
3) Modified Balance Error Scoring System (mBESS).
Number of Items
Symptom evaluation: 22
Standardized Assessment of Concussion: 30
Modified Balance Error Scoring System: 3
Equipment Required
- Stop watch
Time to Administer
15-25 minutes
Required Training
Reading an Article/ManualAge Ranges
13 - 65
yearsInstrument Reviewers
Wade Welton, MS, LAT, ATC
ICF Domain
Body FunctionBody Structure
Professional Association Recommendation
NATA Position Statement (Broglio et al., 2014):
- Athletes at high risk for concussion should undergo baseline examinations before the competitive season. When the rapid assessment of concussion is necessary, a brief concussion-evaluation tool (e.g., Standardized Assessment of Concussion (SAC)) should be used in conjunction with a motor-control evaluation and symptom assessment to support the physical and neurologic clinical evaluation.
Considerations
- Any athlete suspected of having a concussion should be removed from play and not allowed to return to play on the same day of injury.
- If an athlete is suspected of having a concussion and a medically trained individual is not immediately available, the athlete should be referred to a medical facility for assessment.
- Athletes suspected of having a concussion should not consume alcohol and drugs, and they should not drive a motor vehicle until medically cleared.
- Repeated evaluation should be part of concussion assessment as signs and symptoms evolve over time.
- The diagnosis of a concussion is a clinical judgement made by a medical professional. The SCAT3 should not be used as the sole means of concussion diagnosis. Concussion may still be present even if SCAT3 is normal.
Mixed Conditions
back to PopulationsStandard Error of Measurement (SEM)
SCAT 3: (Chin, Nelson, Barr, McCrory, & McCrea, 2016; n=166; mean time post pre-season baseline= 196 days; post-test also performed at 7 days).
Post-Concussion Time | Symptom Score (points) | SAC (Points) | mBESS (Points) |
24 Hours | 13.78 | 2.09 | 2.01 |
8 Days | 7.98 | 1.55 | 1.86 |
15 Days | 3.96 | 1.55 | 1.60 |
45 Days | 2.38 | 1.52 | 1.73 |
SAC: (Barr & McCrea, 2000; n = 68; mean age = 17.2 years; mean interval between baseline testing and time of injury = 46.9 days).
- SEM (n = 68): 1.03 points
BESS: (Riemann, Guskiewicz & Shields; n = 111; mean age = 19.8 (1.4) years; mean height = 182.0 cm (8.5 cm); Weight = 91.7 kg (20.5 kg)
- SEM (n = 18): Single leg stance of firm surface for postural stability = 0.45 (Errors)
- SEM (n = 18): Tandem leg stance of firm surface for postural stability = 0.04 (Errors)
Symptom Evaluation: (Lovell et al., 2006; N = 1,746 high school and university student athletes; 15 high schools, 10 universities; n = 1391 young men; n = 355 young women).
Group | N | SEM1 (Symptom scores- points) | 0.802 (Symptom scores- Points) |
Normative High School |
|
|
|
Young men | 588 | 2.62 | 3.35 |
Young women | 119 | 3.36 | 4.30 |
College |
|
|
|
Young men | 803 | 2.60 | 3.33 |
Young women | 236 | 3.57 | 4.57 |
Combined sample |
|
|
|
Young men | 1391 | 2.66 | 3.40 |
Young women | 355 | 3.46 | 4.43 |
Athletes with concussions |
|
|
|
Young men | 217 | 5.13 | 6.57 |
Young women | 43 | 6.34 | 8.12 |
Combined sample | 260 | 5.29 | 6.77 |
1Standard error of measurement; 2Confidence interval
Minimal Detectable Change (MDC)
SCAT3: (Chin, Nelson, Barr, McCrory, & McCrea, 2016: n = 166; mean time post pre-season baseline = 196 days; post-test also performed at 7 days).
| Symptom Score (Points) | SAC (Points) | mBESS (Points) |
24 Hours | 38.08 | 5.78 | 5.55 |
8 Days | 22.05 | 4.28 | 5.14 |
15 Days | 10.94 | 4.28 | 4.42 |
45 Days | 6.58 | 4.20 | 4.78 |
SAC: (Barr & McCrea, 2000)
- MDC in concussion patients (n = 68): 1.85 (Points)
BESS: (Riemann, Guskiewicz, & Shields, 1999)
- MDC for postural stability on single leg stance on firm surface (n = 18): 1.24 (errors)
- MDC for postural stability on tandem leg stance on firm surface (n = 18): 0.11 (errors)
Symptom Evaluation: (Lovell, Iverson, Collins, Podell, Johnston, & Pardini, 2006)
Group | N | MDC1 (Points) |
Normative High School |
|
|
Young men | 588 | 7.24 |
Young women | 119 | 9.29 |
College |
|
|
Young men | 803 | 7.19 |
Young women | 236 | 9.87 |
Combined sample |
|
|
Young men | 1391 | 7.35 |
Young women | 355 | 9.56 |
Athletes with concussions |
|
|
Young men | 217 | 14.18 |
Young women | 43 | 17.52 |
Combined sample | 260 | 14.62 |
1 Minimal Detectable Change
Minimally Clinically Important Difference (MCID)
SAC: (Barr & McCrea, 2000; n = 50; mean age = 17.2; mean interval between baseline testing and time of injury = 46.9 days).
- MCID (n = 50): 3*
*Increase or decrease in test score of 3 = significant change in performance at 90% confidence level
Cut-Off Scores
SCAT3: (Chin, Nelson, Barr, McCrory & McCrea, 2016: N = 166)
Symptom Score
- Cut-off score for concussed athlete at 24 hours post-concussion interval (n = 164); ≥ 11 points.
- Cut-off score for concussed athlete at day 8 post-concussion interval (n = 164); ≥ 6 points
- Cut-off score for concussed athlete at day 15 post-concussion interval (n = 164); ≥ 4 points
- Cut-off score for concussed athlete at day 45 post-concussion interval (n = 164); ≥ 3 points
SAC
- Cut-off score for concussed athlete at 24 hours post-concussion interval (n = 164); ≥ 26.4 points
- Cut-off score for concussed athlete at day 8 post-concussion interval (n = 164); ≥ 27.10 points
- Cut-off score for concussed athlete at day 15 post-concussion interval (n = 164); ≥ 26.9 points
- Cut-off score for concussed athlete at day 45 post-concussion interval (n = 164); ≥ 27 points
mBESS
- Cut-off score for concussed athlete at 24 hours post-concussion interval for (n = 164); ≥ 3.58 errors
- Cut-off score for concussed athlete at day 8 post-concussion interval (n = 164); ≥ 3.1 errors
- Cut-off score for concussed athlete at day 15 post-concussion interval (n = 164); ≥ 2.9 errors
- Cut-off score for concussed athlete at day 45 post-concussion interval (n = 164); ≥ 3.1 errors
SAC: (Barr & McCrea, 2000)
- Combined sensitivity and specificity was the highest to the effects of concussion at a value of 1.70 points.
- Reliable change indices ≥ 3 indicates clinical significance at a 90% confidence level.
Normative Data
SAC: (McCrea, Kelly, Randolph, Kluge, Bartolic, Finn, & Baxter, 1998; n=353 high school football players; n=215 college football players; preseason baseline testing).
| Normal Controls (n = 568) Mean Points(SD) | Concussed Players (n = 33) Mean Points (SD) | p |
Orientation | 4.82 (.43) | 4.30 (1.24) | < .0001 |
Memory | 14.51 (.98) | 13.03 (1.81) | < .0001 |
Concentration | 3.40 (1.27) | 2.64 (1.06) | < .0007 |
Delayed Recall | 3.84 (1.11) | 2.91 (1.28) | < .0001 |
Total Score | 26.58 (2.23) | 22.88 (3.14) | < .0001 |
Symptom Evaluation: (Lovell, Iverson, Collins, Podell, Johnston, & Pardini et al., 2006; N = 1,746 high school and university student athletes; 15 high schools, 10 universities, n = 1,391 young men, n = 355 young women)
| Normative Sample (Percentage) |
| Concussed Sample (Percentage) |
|
Classification1 | Young men | Young Women | Young Men | Young Women |
Low-normal | 42 | 28 | 6.5 | 2.3 |
Broadly normal | 32 | 45 | 14.7 | 23.3 |
Borderline | 15 | 17 | 11.5 | 23.2 |
Very high | 8 | 7 | 32.7 | 25.6 |
Extremely high | 2 | 2 | 34.6 | 25.6 |
1 descriptors reflecting raw score ranges and percentile rank ranges in the natural distribution of scores
SCAT 2 & 3: (Zimmer, Marcinak, Hibyan, & Webbe, 2014; n = 477 (332 male; 145 female); average age = 19.24 years; participants were members of 14 sports including: football, lacrosse, basketball, soccer, tennis, swimming, track and field, baseball, softball, cross country, golf, crew, cheerleading, and volleyball).
|
|
| Means and Standard Deviation for the Total Sample |
Score | N | M (Mean point values) | SD (Points) |
Symptom Total1 | 476 | 1.75 | 3.00 |
Balance Total | 475 | 25.64 | 4.07 |
SAC Total | 476 | 27.17 | 2.01 |
SCAT 2 Total | 475 | 91.08 | 5.60 |
1 represents actual mean symptom frequency
SCAT 3: (Chin, Nelson, Barr, McCrory & McCrea, 2016: n = 164)
Symptom Score
- Adequate test-retest reliability (ICC = 0.43)
SAC
- Poor test-retest reliability (ICC = 0.39)
mBESS
- Adequate test-retest reliability (ICC = 0.54)
SAC: (Barr & McCrea, 2000)
- Adequate test-retest reliability (r = 0.55)
SCAT : (Mrazik, Lenchyshyn, Borza & Naidu, 2017; N = 165; mean age = 21.26 years; athletes from a Canadian university)
| Intraclass Correlation | Pearson r Correlation |
Frequency |
|
|
History of Concussion (n = 67) |
|
|
Symptom Total | 0.68 = Adequate reliability | 0.69 = Adequate reliability |
Severity Total | 0.70 = Adequate reliability | 0.67 = Adequate reliability |
Balance Total | 0.88 = Excellent Reliability | 0.87 = Excellent Reliability |
SAC Total | 0.77 = Excellent Reliability | 0.89 = Excellent Reliability |
No History of Concussion (n = 85) |
|
|
Symptom Total | 0.60 = Adequate reliability | 0.66 = Adequate reliability |
Severity Total | 0.55 = Adequate reliability | 0.60 = Adequate reliability |
Balance Total | 0.84 = Excellent Reliability | 0.91 = Excellent Reliability |
SAC Total | 0.78 = Excellent Reliability | 0.91 = Excellent Reliability |
Test/Retest Reliability
SCAT 3: (Chin, Nelson, Barr, McCrory & McCrea, 2016: n = 164)
Symptom Score
- Adequate test-retest reliability (ICC = 0.43)
SAC
- Poor test-retest reliability (ICC= 0.39)
mBESS
- Adequate test-retest reliability (ICC = 0.54)
SAC: (Barr & McCrea, 2000)
- Adequate test-retest reliability (r = 0.55)
SCAT : (Mrazik, Lenchyshyn, Borza & Naidu, 2017; N = 165; mean age = 21.26; athletes from a Canadian university)
| Intraclass Correlation | Pearson r Correlation |
Frequency |
|
|
History of Concussion (n = 67) |
|
|
Symptom Total | 0.68 = Adequate reliability | 0.69 = Adequate reliability |
Severity Total | 0.70 = Adequate reliability | 0.67 = Adequate reliability |
Balance Total | 0.88 = Excellent Reliability | 0.87 = Excellent Reliability |
SAC Total | 0.77 = Excellent Reliability | 0.89 = Excellent Reliability |
No History of Concussion (n = 85) |
|
|
Symptom Total | 0.60 = Adequate reliability | 0.66 = Adequate reliability |
Severity Total | 0.55 = Adequate reliability | 0.60 = Adequate reliability |
Balance Total | 0.84 = Excellent Reliability | 0.91 = Excellent Reliability |
SAC Total | 0.78 = Excellent Reliability | 0.91 = Excellent Reliability |
Interrater/Intrarater Reliability
SCAT 3: (Chin, Nelson, Barr, McCrory & McCrea, 2016: n = 164)
Symptom Score
- Adequate interrater reliability at 7 day interval (ICC = 0.62)
SAC
- Poor interrater reliability at 7-day interval (ICC = 0.39)
mBESS
- Adequate interrater reliability at 7-day interval (ICC = 0.52)
BESS: (Riemann, Guskiewicz, & Shields, 1999)
- Excellent inter-rater reliability for postural stability with single leg stance on firm surface (ICC = 0.93)
- Excellent inter-rater reliability for postural stability with tandem stance on firm surface (ICC = 0.96)
Internal Consistency
Symptom Evaluation: (Lovell, Iverson, Collins, Podell, Johnston, & Pardini et al., 2006)
- Excellent internal consistency (Cronbach’s alpha = 0.93)
Criterion Validity (Predictive/Concurrent)
Concurrent Validity:
BESS: (Riemann, Guskiewicz & Shields, 1999; n = 111)
- Adequate correlation for postural stability between BESS error scores and target sway measures for single leg stance on firm surface (r = 0.4205)
- Adequate correlation for postural stability between BESS error scores and target sway measures for tandem leg stance on firm surface (r = 0.5887)
Predictive Validity:
SAC: (Barr & McCrea, 2000)
- Excellent Area Under the Curve: (AUC = 0.939, SE = 0.021)
Construct Validity
SAC: (McCrea, Kelly, Randolph, Kluge, Bartolic, Finn, & Baxter, 1998; n = 33; assessed for concussion immediately following injury and 48 hours post-injury)
- Players displayed a statistically significant drop in score after concussion as compared to pre-injury baseline scores: t = 4.6; p < .0001
- Orientation: t = 2.7; p < .01
- Immediate memory: t = 4.6; p < .0001
- Concentration: t = 2.4; p < .02
- Delayed Recall: t = 2.0; p < .05; approached significance
Floor/Ceiling Effects
SAC: (McCrea, Kelly, Randolph, Kluge, Bartolic, Finn, & Baxter,1998; n = 568; average score for normal subjects)
- Average score for normal subjects falls 1.60 standard deviations below ceiling.
- Adequate Ceiling effect: 7% of normal subjects managed a perfect score of 30 points.
Responsiveness
SCAT 3: (Chin, Nelson, Barr, McCrory & McCrea, 2016)
- Large responsiveness for Symptom Score 24 hours post-injury (Effect Size (ES) = 1.52); n = 166
- Small responsiveness for SAC 24 hours post-injury (ES= -0.36); n = 166
- Moderate responsiveness for mBESS 24 hours post-injury (ES = 0.46); n = 166
Bibliography
Barr, W., & McCrea, M. (2001). Sensitivity and specificity of standardized neurocognitive testing immediately following sports concussion. Journal of The International Neuropsychological Society, 7(6), 693-702. http://dx.doi.org/10.1017/s1355617701766052
Broglio, S., Cantu, R., Gioia, G., Guskiewicz, K., Kutcher, J., Palm, M., & McLeod, T. (2014). National Athletic Trainers' Association Position Statement: Management of Sport Concussion. Journal Of Athletic Training, 49(2), 245-265. http://dx.doi.org/10.4085/1062-6050-49.1.07
Chin, E., Nelson, L., Barr, W., McCrory, P., & McCrea, M. (2016). Reliability and Validity of the Sport Concussion Assessment Tool–3 (SCAT3) in High School and Collegiate Athletes. The American Journal Of Sports Medicine, 44(9), 2276-2285. http://dx.doi.org/10.1177/0363546516648141
Lovell, M., Iverson, G., Collins, M., Podell, K., Johnston, K., & Pardini, D. et al. (2006). Measurement of Symptoms Following Sports-Related Concussion: Reliability and Normative Data for the Post-Concussion Scale. Applied Neuropsychology, 13(3), 166-174. http://dx.doi.org/10.1207/s15324826an1303_4
McCrea, M., Kelly, J., Randolph, C., Kluge, J., Bartolic, E., Finn, G., & Baxter, B. (1998). Standardized Assessment of Concussion (SAC): On-Site Mental Status Evaluation of the Athlete. Journal Of Head Trauma Rehabilitation, 13(2), 27-35. http://dx.doi.org/10.1097/00001199-199804000-00005
Mrazik, M., Lenchyshyn, J., Borza, C., & Naidu, D. (2017). Psychometric Properties of a Concussion Evaluation Tool in College Athletes. EC Psychology And Psychiatry, 4(3), 85-93.
Riemann, B., Guskiewicz, K., & Shields, E. (1999). Relationship between Clinical and Forceplate Measures of Postural Stability. Journal Of Sport Rehabilitation, 8(2), 71-82. http://dx.doi.org/10.1123/jsr.8.2.71
Zimmer, A., Marcinak, J., Hibyan, S., & Webbe, F. (2014). Normative Values of Major SCAT2 and SCAT3 Components for a College Athlete Population. Applied Neuropsychology: Adult, 22(2), 132-140. http://dx.doi.org/10.1080/23279095.2013.867265