Table 3. Principal components analysis and reliability analysis for Test A.
| Correct answers Mean (Standard Deviation) % Correct response |
Principal component analysis |
||||
|---|---|---|---|---|---|
| Patients | Controls | Reliability analysis | Corrected Item-Total Correlation | Cronbach’s Alpha if Item Deleted | |
| Word categories task | 8.24 (4.49) 81.4% | 11.59 (4.03) 92.1% | 0.818 | 0.744 | 0.888 |
| Attention task II | 19.94 (10.79) 93.7% | 22.16 (7.79) 98.0% | 0.698 | 0.614 | 0.900 |
| Sequences | 5.24 (3.53) 88.0% | 8.80(4.16) 97.0% | 0.777 | 0.704 | 0.892 |
| Visual memory task I | 5.59 (2.68) 84.8% | 6.22 (1.82) 93.6% | 0.495A | – | – |
| Puzzles | 2.00 (1.37) 100% | 2.71 (1.79) 100% | 0.693 | 0.614 | 0.900 |
| Written comprehension | 14.18 (3.22) 88.0% | 15.35 (3.49) 97.9% | 0.789 | 0.717 | 0.891 |
| Shopping task | 3.90 (2.88) 88.0% | 6.29 (3.22) 96.0% | 0.803 | 0.728 | 0.890 |
| Verbal memory task | 4.02 (2.14) 89.1% | 4.96 (2.36) 96.8% | 0.774 | 0.704 | 0.892 |
| Inhibitory control | 23.94 (8.46) 86.1% | 26.18 (8.08) 97.7% | 0.819 | 0.750 | 0.888 |
Overall Cronbach’s Alpha = 0.91; Variance explained by the first component was 55.8%.
ASubtest discarded after observing the principal component analysis results (factor loading <0.50).