ROC characteristics for between diagnostic group comparisons at optimal thresholds, determined using a ‘closest top left’ algorithm
| Threshold | Specificity (95% CI) | Sensitivity (95% CI) | PPV | NPV | |
|---|---|---|---|---|---|
| PSP vs PD | |||||
| ACE-R | 83.5 | 0.87 (0.80 to 0.94) | 0.70 (0.53 to 0.87) | 0.66 | 0.89 |
| MMSE | 27.5 | 0.80 (0.72 to 0.88) | 0.67 (0.50 to 0.83) | 0.54 | 0.87 |
| Fluency | 7.5 | 0.93 (0.87 to 0.98) | 0.87 (0.73 to 0.97) | 0.81 | 0.95 |
| Combined raw fluencies | 20.5 | 0.89 (0.81 to 0.95) | 0.87 (0.73 to 0.97) | 0.74 | 0.95 |
| Visuospatial | 14.5 | 0.84 (0.77 to 0.92) | 0.73 (0.57 to 0.87) | 0.63 | 0.90 |
| CBD vs PD | |||||
| ACE-R | 87 | 0.77 (0.67 to 0.85) | 0.74 (0.53 to 0.89) | 0.41 | 0.93 |
| MMSE | 25.5 | 0.94 (0.88 to 0.99) | 0.37 (0.16 to 0.58) | 0.58 | 0.87 |
| Fluency | 8.5 | 0.83 (0.74 to 0.91) | 0.63 (0.42 to 0.84) | 0.44 | 0.91 |
| Combined raw fluencies | 24.5 | 0.76 (0.66 to 0.84) | 0.68 (0.47 to 0.89) | 0.40 | 0.91 |
| Visuospatial | 13.5 | 0.92 (0.85 to 0.98) | 0.68 (0.47 to 0.89) | 0.65 | 0.93 |
| PSP vs CBD | |||||
| ACE-R | 79.5 | 0.63 (0.42 to 0.84) | 0.63 (0.47 to 0.80) | 0.73 | 0.52 |
| MMSE | 27.5 | 0.58 (0.37 to 0.79) | 0.67 (0.5 to 0.83) | 0.71 | 0.52 |
| Fluency | 7.5 | 0.58 (0.37 to 0.79) | 0.87 (0.73 to 0.97) | 0.81 | 0.97 |
| Combined raw fluencies | 16.5 | 0.79 (0.58 to 0.95) | 0.67 (0.5 to 0.83) | 0.83 | 0.60 |
| Visuospatial | 10.5 | 0.26 (0.11 to 0.47) | 0.9 (0.8 to 1.0) | 0.70 | 0.45 |
Corresponding ROC curves are shown in figure 2.
ACE-R, Addenbrooke's Cognitive Examination Revised; CBD, corticobasal degeneration; MMSE, Mini Mental State Examination; NPV, negative predictive value; PD, Parkinson's disease; PPV, positive predictive value; PSP, progressive supranuclear palsy; ROC, receiver operating characteristics.