Table 4.
Performance of cortical thickness signature scores with the hazard ratio for total conversion and sensitivity/specificity for differentiating dementia-first vs. motor-first conversion in iRBD
| Total disease conversion in iRBD | Hazard ratio [95% Confidence interval] |
|---|---|
| MRI (DLB-pattern) | 2.27 [0.70, 7.61] |
| MRI(Mean cortical thickness) | 9.33 [1.16, 74.12] |
| 18F-FP-CIT PET (posterior putamen SUVR < 0.65) | 8.65 [2.54, 29.41] |
| Hyposmia (B-SIT) | 4.38 [1.47, 13.08] |
| Objective motor examination* | 2.89 [0.91, 9.18] |
| Dementia-first (n = 7) vs Parkinsonism-first (n = 10) among the converters | Overall discrimination | ||
|---|---|---|---|
| Sensitivity (%) | Specificity (%) | Diagnostic accuracy (%) | |
| MRI (DLB-pattern) | 85.7 | 90 | 88.2 |
| MRI (Mean cortical thickness) | 85.7 | 0 | 35.3 |
| 18F-FP-CIT PET (posterior putamen SUVR < 0.65) | 57.1 | 10 | 29.4 |
| Hyposmia (B-SIT) | 66.7 | 33.3 | 31.3 |
| Objective motor examination* | 85.7 | 30.0 | 58.2 |
*Objective motor examination was defined by UPDRS part III score > 3 excluding action tremor[1]
AD Alzheimer’s dementia, B-SIT Brief smell identification test, DLB Dementia with Lewy bodies, iRBD Idiopathic rapid-eye-movement sleep behavior disorder, SUVR Standardized uptake ratio
Sensitivity, specificity and diagnostic accuracy were calculated by detection of dementia-first converters among total converters as follows
a = number of dementia-first converters with positive biomarker
b = number of total dementia-converters
c = number of motor-first converters with negative biomarker
d = number of total motor-first converters
(a/b for sensitivity, c/d for specificity and (a + c)/(a + b + c + d) for diagnostic accuracy)