Table 4.

Comparison of performance on tests of global cognitive efficiency, memory, and mood before and after electrode implantation (stimulator turned “on”)

TestBefore3 months12 monthsp Value
Values are mean (SD). Boldface indicates statistical significance. Two groups are described, one with stimulation of the subthalamic nucleus (STN1), one with stimulation of the internal globus pallidus (GPi1). p = global effect of time of assessment.
Mattis Dementia Rating Scale
Total score
STN1137.0 (4.7)136.6 (5.5)136.7 (7.0)0.80
GPi1137.3 (5.3)134.8 (4.8)139.5 (3.0)0.07
Attention
STN136.0 (0.9)36.0 (0.9)35.8 (1.1)0.60
GPi136.0 (0.8)35.9 (0.6)35.8 (1.2)0.86
Initiation
STN133.9 (3.8)33.4 (3.9)33.2 (4.5)0.50
GPi133.9 (3.4)32.3 (3.7)36.6 (0.7)0.02
Construction
STN16.0 (0.0)6.0 (0.0)6.0 (0.0)1.0
GPi16.0 (0.0)6.0 (0.0)6.0 (0.0)1.0
Conceptualization
STN137.4 (1.7)37.2 (2.0)37.4 (1.8)0.39
GPi136.6 (1.8)36.3 (1.8)36.5 (1.8)0.88
Memory
STN123.9 (1.1)24.0 (1.2)24.2 (1.1)0.33
GPi124.8 (0.5)24.4 (0.7)24.6 (1.1)0.23
Grober and Buschke Verbal Learning Test
Free recall
STN128.8 (5.8)26.4 (6.3)28.5 (7.5)0.02
GPi126.0 (7.2)25.7 (7.1)27.0 (7.1)0.86
Total recall
STN146.4 (2.2)45.8 (3.1)46.6 (1.8)0.13
GPi146.2 (3.1)45.8 (1.8)45.2 (3.8)0.70
Delayed free recall
STN110.8 (2.5)9.9 (2.8)10.2 (3.0)0.18
GPi110.2 (2.1)10.3 (2.7)11.7 (2.7)0.35
Delayed total recall
STN115.9 (0.3)15.6 (0.9)15.7 (0.7)0.16
GPi115.7 (0.5)15.2 (1.6)15.7 (0.5)0.63
Beck Depression Scale
STN115.1 (7.0)11.0 (7.8)11.9 (7.8)0.0005
GPi113.7 (7.2)9.1 (6.1)10.0 (5.4)0.35