Table 3. Descriptive statistics including mean, standard deviation (SD), Cronbach’s alpha (α) at each occasion and test–retest reliability for the RPQ (n = 145 × 3 occasions).
| Item | Mean | SD | α | Test–retest (ICC, r) |
|---|---|---|---|---|
| 1. Headaches | 1.2 | 1.2 | ||
| 2. Feelings of dizziness | 1.0 | 1.1 | ||
| 3. Nausea and /or vomiting | 0.4 | 0.8 | ||
| 4. Noise sensitivity | 0.8 | 1.1 | ||
| 5. Sleep disturbance | 1.2 | 1.2 | ||
| 6. Fatigue, tiring more easily | 1.4 | 1.3 | ||
| 7. Irritable, easily angered | 1.0 | 1.1 | ||
| 8. Depressed or tearful | 0.7 | 1.0 | ||
| 9. Frustrated or impatient | 1.1 | 1.1 | ||
| 10. Forgetful, poor memory | 1.4 | 1.2 | ||
| 11. Poor concentration | 1.2 | 1.2 | ||
| 12. Taking longer to think | 1.3 | 1.2 | ||
| 13. Blurred vision | 0.8 | 1.1 | ||
| 14. Light sensitivity | 0.8 | 1.2 | ||
| 15. Double vision | 0.4 | 0.8 | ||
| 16. Restlessness | 1.0 | 1.1 | ||
| Occasion | ||||
| 1 (Baseline/within 1 month) | 1.0 | 1.2 | ||
| 2 (6 months post-injury ) | 1.0 | 1.2 | ||
| 3 (12 months post-injury) | 1.0 | 1.2 | ||
| RPQ 16 Items summed score | (ICC) .63(CI ± .08) | |||
| 1 (Baseline/within 1 month) | 19.5 | 13.6 | .94 | – |
| 2 (6 months post-injury) | 14.4* | 12.5 | .95 | (r) .57(CI ± .10) |
| 3 (12 months post-injury) | 12.9* | 12.2 | .94 | (r) .56(CI ± .10) |
Notes.
Note: Grand mean, 1.0; SD, 1.2; ICC, Intraclass Correlation Coefficient across three occasions; r, Pearson’s correlation between baseline (1) time 2 and 3; CI, 95% Confidence Interval.
*
Significant mean difference compared to the baseline using paired t-test p < .001.