Subject characteristics
| Normal controls (n=23) mean (SD) | Frontal lobe patients (n=9) mean (SD) | p | |
| Age | 68.3 (7.2) | 61.2 (16.3) | NS |
| Education (y) | 16.1 (3.0) | 15.4 (2.5) | NS |
| Estimated IQ | 121.5 (5.5) | 116.4 (10.0) | NS |
| Zung score (20–80) | 30.8 (5.1) | 37.0 (11.7) | NS |
| Apathy scores | |||
| • Self report scale (0–42) | 5.9 (3.7) | 11.3 (6.5) | p<0.04 |
| • Informant based inventory (0–40) | 6.1 (5.0) | 17.0 (6.4) | p<0.00005 |
For both Zung and apathy scales, higher numbers indicate more severe symptomatology.