Table 2.

Comparison of performance on tests of executive function before electrode implantation and after, with stimulator turned “off” and “on”

TestBefore3 monthsp Value*12 monthsp Value†Time, p Value‡
“off”“on”“off”“on”
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, † p, effect of stimulation; ‡, p, global effect of time of assessment.
Wisconsin Card Sorting Test
Criteria
STN15.1 (1.1)5.1 (1.2)5.3 (1.0)0.185.1 (1.5)5.2 (1.2)0.390.52
GPi15.1 (1.4)4.9 (1.7)5.1 (1.1)0.795.5 (1.4)5.0 (0.9)0.100.69
Perseverations
STN12.4 (2.1)2.0 (2.5)1.8 (1.8)0.492.8 (3.6)2.5 (2.6)0.490.11
GPi12.9 (2.2)1.6 (1.8)3.1 (2.6)0.243.1 (4.9)2.3 (2.2)0.920.48
Abandons
STN11.0 (1.3)1.1 (1.3)1.0 (1.2)0.341.0 (1.3)1.2 (1.9)0.520.43
GPi11.0 (1.2)1.6 (2.3)0.9 (1.4)0.110.5 (0.8)1.1 (1.1)0.060.69
Lexical fluency
Category
STN114.6 (3.9)12.3 (4.1)12.7 (4.2)0.4312.1 (4.0)12.9 (3.7)0.210.0006
GPi114.8 (3.9)12.4 (1.3)12.9 (3.9)0.9313.5 (5.0)13.8 (1.8)0.780.34
Literal
STN112.3 (5.0)10.8 (4.8)11.0 (4.9)0.6511.1 (4.7)11.3 (4.9)0.640.08
GPi110.6 (4.6)11.1 (3.3)11.5 (3.5)0.4612.8 (4.5)12.3 (4.1)0.730.27
Series
Graphic
STN18.2 (2.2)7.5 (3.1)7.9 (2.9)0.227.4 (2.7)8.2 (2.6)0.020.56
GPi18.1 (2.7)8.1 (2.8)7.0 (3.3)0.296.0 (3.7)6.7 (2.6)0.600.23
Motor
STN18.5 (2.5)8.8 (2.1)8.6 (2.1)0.348.5 (1.9)8.8 (1.9)0.180.73
GPi19.3 (0.7)8.1 (3.5)8.9 (1.6)0.299.7 (0.8)9.0 (2.2)0.690.78
Stroop Test
Words
STN196.4 (17.5)96.0 (15.8)96.0 (13.6)0.5290.4 (16.0)96.9 (18.8)0.00140.92
GPi187.0 (16.0)92.2 (12.1)93.6 (16.8)0.7597.6 (9.7)92.6 (13.1)0.930.88
Colors
STN162.9 (10.6)60.0 (13.1)61.1 (11.1)0.3857.6 (15.0)60.0 (13.2)0.020.89
GPi162.8 (5.3)63.0 (3.1)62.6 (7.5)0.5065.4 (6.1)63.6 (11.0)0.670.85
Colors of words
STN135.7 (8.6)33.8 (10.1)34.8 (7.6)0.2134.4 (10.0)35.6 (10.0)0.260.93
GPi136.0 (10.8)39.0 (8.3)35.0 (5.2)0.1740.0 (12.6)40.9 (11.6)0.500.74
Trail Making Test
A
STN157.2 (20.6)59.6 (31.7)54.2 (30.4)0.0462.2 (30.3)53.6 (15.4)0.050.16
GPi159.6 (24.7)53.0 (13.7)44.9 (13.0)0.1154.0 (7.7)44.7 (9.5)0.170.22
B
STN1136.8 (64.8)154.7 (129.7)136.9 (142.4)0.13142.0 (75.0)119.1 (47.6)0.010.01
GPi1131.6 (50.3)130.0 (75.4)111.9 (57.2)0.13105.3 (37.8)97.0 (30.8)0.690.22
B-A
STN179.6 (50.4)102.4 (111.3)89.5 (119.1)0.2379.9 (53.9)66.4 (36.9)0.060.16
GPi172.0 (27.6)77.0 (64.8)67.0 (49.2)0.2450.8 (32.2)52.3 (27.7)0.680.31