Table 4.
Results of ROC analysis
| Cognitive test | Smell test score cut-off* | ||||||
|---|---|---|---|---|---|---|---|
| < 8 | < 9 | < 10 | < 11 | < 12 | AUC (95% CI) | ||
| VF | Sensitivity | 10.4 | 19.0 | 37.8 | 63.0 | 86.4 | 0.55 |
| Specificity | 92.1 | 84.8 | 69.3 | 44.4 | 16.1 | (0.52–0.57) | |
| Youden’s index | 2.5 | 3.8 | 7.1 | 7.4 | 2.5 | p < 0.001 | |
| WLL | Sensitivity | 15.7 | 28.1 | 50.0 | 71.5 | 92.6 | 0.58 |
| Specificity | 89.4 | 79.9 | 63.3 | 39.8 | 13.5 | (0.55–0.62) | |
| Youden’s index | 5.1 | 8.0 | 13.3 | 11.3 | 6.1 | p < 0.001 | |
| WLR | Sensitivity | 15.9 | 32.6 | 49.2 | 72.0 | 93.2 | 0.59 |
| Specificity | 89.1 | 79.8 | 62.5 | 39.2 | 13.2 | (0.54–0.64) | |
| Youden’s index | 5.0 | 12.4 | 11.7 | 9.4 | 6.4 | p = 0.001 | |
| TMT-A | Sensitivity | 14.9 | 29.6 | 50.4 | 71.3 | 90.4 | 0.62 |
| Specificity | 92.2 | 85.3 | 69.8 | 44.5 | 16.2 | (0.59–0.65) | |
| Youden’s index | 7.1 | 14.9 | 20.2 | 15.8 | 6.6 | p < 0.001 | |
| TMT-B/A | Sensitivity | 10.5 | 19.1 | 38.3 | 63.8 | 88.2 | 0.55 |
| Specificity | 92.1 | 84.8 | 69.3 | 44.4 | 16.2 | (0.53–0.58) | |
| Youden’s index | 2.6 | 3.9 | 7.6 | 8.2 | 4.4 | p < 0.001 | |
Youden’s index = sensitivity + specificity − 1. Highest Youden’s index is indicated in italics
Sensitivity, specificity, and Youden’s index are given as percentages
*Individuals having a smell test score below the cut-off are “test positive”, i.e., suspected of being cognitively impaired