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  2. Sport Concussion Assessment Tool-3

Sport Concussion Assessment Tool-3

Last Updated

Purpose

The SCAT3 evaluates injured athletes aged 13+ for concussions.

Link to Instrument

Instrument Details

Acronym SCAT3

Administration Mode

Paper & Pencil

Cost

Free

Actual Cost

$0.00

Populations

Non-Specific Patient Population

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/Manual

Age Ranges

13 - 65

years

Instrument Reviewers

Wade Welton, MS, LAT, ATC

ICF Domain

Body Function
Body 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 Populations

Standard 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

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