TABLE II.
Support vector machine learning classification discriminative measures. Training/Validation measures represent the averages with 95% confidence intervals during 5-fold cross-validation. Test measures represent the performance in the test dataset. Sample sizes for each comparison for the Training/Valiation and Test phases of machine learning can be found in Figure 2. Abbreviations: dMRI, diffusion MRI; MDS-UPDRS III, Movement Disorders Society Unified Parkinson’s Disease Rating Scale part III; AUC, area under the receiver operating characteristic curve; PPV, positive predictive value; NPV, negative predictive value; CON, control; PD, Parkinson’s disease; MSA, multiple system atrophy; PSP, progressive supranuclear palsy.
| PD vs. Atypical | ||||||
| dMRI + MDS-UPDRS III | dMRI Only | MDS-UPDRS III Only | ||||
| Training/Validation | Test | Training/Validation | Test | Training/Validation | Test | |
| AUC | 0·969 [0·955, 0·982] | 0·962 | 0·961 [0·943, 0·979] | 0·955 | 0·745 [0·701, 0·789] | 0·775 |
| Accuracy (%) | 85·06 [82·57, 87·55] | 91·49 | 85·21 [83·43, 86·98] | 90·24 | 63·00 [59·32, 66·68] | 66·61 |
| Sensitivity (%) | 79·23 [74·16, 84·30] | 92·5 | 78·05 [74·65, 81·45] | 90·00 | 41·53 [32·90, 50·16] | 67·50 |
| Specificity (%) | 90·89 [88·38, 93·40] | 90·48 | 92·37 [89·28, 95·45] | 90·48 | 84·47 [78·46, 90·48] | 65·71 |
| PPV (%) | 89·79 [87·16, 92·14] | 90·67 | 91·29 [88·07, 94·51] | 90·43 | 73·47 [66·24, 80·70] | 66·32 |
| NPV (%) | 81·64 [77·92, 85·36] | 92·35 | 90·91 [88·55, 93·27] | 90·05 | 59·36 [56·13, 62·59] | 66·91 |
| MSA vs. PSP | ||||||
| dMRI + MDS-UPDRS III | dMRI Only | MDS-UPDRS III Only | ||||
| Training/Validation | Test | Training/Validation | Test | Training/Validation | Test | |
| AUC | 0·971 [0·943, 0·998] | 0·897 | 0·965 [0·937, 0·992] | 0·926 | 0·765 [0·693, 0·838] | 0·582 |
| Accuracy (%) | 87·99 [84·23, 91·74] | 80·13 | 84·85 [79·65, 90·05] | 81·79 | 69·97 [62·07, 77·87] | 50·90 |
| Sensitivity (%) | 85·89 [79·50, 92·28] | 83·33 | 83·89 [77·52, 90·26] | 86·67 | 66·79 [57·57, 76·01] | 63·33 |
| Specificity (%) | 90·10 [86·96, 93·24] | 76·92 | 85·81 [80·11, 91·51] | 76·92 | 73·14 [62·24, 84·04] | 38·46 |
| PPV (%) | 89·70 [86·65, 92·75] | 78·31 | 85·64 [80·18, 91·10] | 78·97 | 72·35 [62·10, 82·60] | 50·72 |
| NPV (%) | 86·83 [81·57, 92·09] | 82·19 | 84·41 [78·79, 90·03] | 85·23 | 68·96 [61·15, 76·77] | 51·19 |