Purpose
The SCAT3 evaluates injured athletes aged 13+ for concussions.
Link to Instrument
Acronym
SCAT3
Primary Image
Sport Concussion Assessment Tool-3
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.
Non-Specific Patient Population
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.
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.
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.
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.
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.
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.
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.