Table 3.
Test-retest reliability, sensitivity, and group differences
| 24- to 48-hour follow-up | 8-day follow-up | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| 22-item | 14-item | 10-item | 5-item | 3-item | 22-item | 14-item | 10-item | 5-item | 3-item | |
| Test-retest reliability (controls)a | .53 | .54 | .53 | .49 | .42 | .51 | .42 | .42 | .40 | .36 |
| Reliable change cutoffs | ||||||||||
| 80th percentile | 7.3 | 5.2 | 4.2 | 3.1 | 2.1 | 7.3 | 5.8 | 4.7 | 3.2 | 2.1 |
| 90th percentile | 9.4 | 6.6 | 5.5 | 3.9 | 2.7 | 9.4 | 7.4 | 6.0 | 4.1 | 2.7 |
| 95th percentile | 11.2 | 7.9 | 6.5 | 4.7 | 3.2 | 11.3 | 8.9 | 7.1 | 4.9 | 3.2 |
| Sensitivity | ||||||||||
| 80% CI | 68.5% | 70.0% | 65.5% | 54.6% | 51.5% | 15.4% | 17.5% | 17.9% | 13.0% | 12.6% |
| 90% CI | 64.0% | 67.8% | 61.1% | 54.6% | 51.5% | 13.1% | 14.3% | 14.3% | 10.8% | 12.6% |
| 95% CI | 57.2% | 65.6% | 58.5% | 51.1% | 41.5% | 11.8% | 13.9% | 12.1% | 10.8% | 9.0% |
| False positive rate in controls | ||||||||||
| 80% CI | 5.7% | 4.3% | 4.8% | 3.4% | 3.9% | 1.8% | 3.1% | 3.6% | 2.2% | 1.8% |
| 90% CI | 3.5% | 3.5% | 3.5% | 3.4% | 3.9% | 1.8% | 1.8% | 2.7% | 2.2% | 1.8% |
| 95% CI | 1.8% | 2.2% | 1.7% | 2.6% | 0.9% | 1.4% | 1.3% | 1.3% | 2.2% | 1.3% |
| Concussed vs. control difference | ||||||||||
| d | 1.45 | 1.51 | 1.46 | 1.35 | 1.27 | 0.40 | 0.44 | 0.39 | 0.31 | 0.33 |
| (95% CI) | (1.24–1.64) | (1.31–1.71) | (1.26–1.66) | (1.16–1.55) | (1.08–1.47) | (0.22–0.58) | (0.26–0.62) | (0.21–0.57) | (0.13–0.49) | (0.15–0.51) |
| Sensitivity (symptomatic) | ||||||||||
| 80% CI | 69.9% | 71.5% | 66.7% | 55.1% | 51.9% | 33.3% | 39.7% | 41.1% | 28.8% | 26.0% |
| 90% CI | 65.1% | 69.2% | 62.0% | 55.1% | 51.9% | 26.4% | 30.1% | 31.5% | 21.9% | 26.0% |
| 95% CI | 57.9% | 66.8% | 59.3% | 51.4% | 41.7% | 22.2% | 28.8% | 26.0% | 21.9% | 17.8% |
| False positive rate (asymptomatic) | ||||||||||
| 80% CI | 12.5% | 12.5% | 12.5% | 12.5% | 12.5% | 2.2% | 2.2% | 2.9% | 2.2% | 2.2% |
| 90% CI | 12.5% | 12.5% | 12.5% | 12.5% | 12.5% | 2.2% | 2.2% | 2.2% | 2.2% | 2.2% |
| 95% CI | 12.5% | 12.5% | 12.5% | 12.5% | 0.0% | 2.2% | 2.2% | 2.2% | 2.2% | 1.4% |
| Positive Predictive Valueb | ||||||||||
| 80% CI | 99.3% | 99.4% | 99.3% | 99.2% | 99.1% | 88.9% | 90.6% | 88.2% | 87.5% | 86.4% |
| 90% CI | 99.3% | 99.3% | 99.3% | 99.2% | 99.1% | 86.4% | 88.0% | 88.5% | 84.2% | 86.4% |
| 95% CI | 99.2% | 99.3% | 99.2% | 99.1% | 100% | 84.2% | 87.5% | 86.4% | 84.2% | 86.7% |
a
Test-retest reliability (r) computed for non-injured controls from preseason baseline to the 24–48-hour or 8-day follow-up.
b
Positive predictive value were calculated using the base rate of concussed athletes remaining symptomatic at each time point (96% at 24–48 hours, 34% at day 8).