Table 6.
Impairment Classification Accuracy of Short Forms Relative to Full Form Score for Parkinson’s Disease Patients
| Odd Form | Even Form | Two-Thirds Form | |
|---|---|---|---|
| Impaired to Unimpaired (False Negative) | 3 (2%) | 7 (5%) | 5 (4%) |
| Impaired to Impaired (True Positive) | 17 (12%) | 13 (9%) | 16 (11%) |
| Unimpaired to Impaired (False Positive) | 6 (4%) | 16 (11%) | 3 (2%) |
| Unimpaired to Unimpaired (True Negative) | 115 (82%) | 105 (75%) | 117 (83%) |
| Classification Change Significance a | p = 0.508 | p = 0.093 | p = 0.727 |
| Sensitivity | .85 | .65 | .76 |
| Specificity | .95 | .88 | .98 |
| Positive Predictive Value | .74 | .45 | .84 |
| Negative Predictive Value | .98 | .94 | .96 |
| Area Under the ROC Curve | .98 b | .90 b | .97 b |
| Brier Score c | .11 | .14 | .10 |
a
Based on the McNemar change test;
b
p < .01;
c
Full-form = .09
Note. A cut-off score of 20 and lower after the application of age and gender correction was used to classify patients as impaired (Benton et al., 1994). These calculations consider “impaired full Judgment of Line Orientation score” as the condition predicted by each Short Form Judgment of Line Orientation score.