Table 4.
Neuropsychological test performance ON and OFF treatment
| Test | STN DBS [mean (± SD)] |
Levodopa [mean (± SD)] |
Reference levela | ||
|---|---|---|---|---|---|
| OFF | ON | OFF | ON | ||
| Brief test of attention | 6.3 (1.9) | 6.3 (2.4) | 6.9 (2.4) | 7.0 (2.4) | 7.9 (1.6) |
| Symbol digit modality test* | 26.9 (6.5) | 29.3 (6.6) | 39.4 (6.6) | 42.0 (7.1) | 41.5 (8.6) |
| Controlled oral word association | 34.1 (16.6) | 34.9 (17.3) | 40.4 (9.0) | 38.1 (11.2) | 35.6 (12.5) |
| Hopkins verbal learning test | |||||
| Trials 1–3 | 20.0 (5.8) | 19.8 (4.6) | 23.4 (6.2) | 24.7 (3.7) | 27.7 (4.3) |
| Delay* | 4.3 (3.9) | 5.9 (1.5) | 6.9 (2.1) | 9.0 (1.0) | 9.9 (1.9) |
| % Retention* | 48.9 (37.5) | 79.1 (15.7) | 73.7 (18.8) | 88.6 (11.9) | 92.4 (14.4) |
| Recognition/discrimination | 8.3 (2.9) | 7.9 (1.4) | 8.0 (2.8) | 11.1 (0.9) | 10.8 (1.3) |
Scores with significant interactions are given in boldface (P < 0.05; see text).
a
Reference based on average age of study participants.
*
Significant main effect of treatment (P < 0.01).