Table 1

Neuropsychological and neurological data at baseline and at follow-up

	Baseline(0 wk)	FU 1 (26 wk)	FU 2 (52 wk)	FU 3 (156 wk)	FU 4 (157 wk)	FU 5 (163 wk)	FU 6 (180 wk)
AVLT, Auditory Verbal Learning Test; COWAT, Controlled Oral Word Association Test; DEX, Dysexecutive Questionnaire; FU, Follow-up; H&Y, Hoehn and Yahr scale; IGT, Iowa Gambling Task; LEU, levodopa equivalent unit; MADRS, Montgomery and Asberg Depression Rating Scale; PASAT, Paced Auditory Serial Addition Test; PDQL, Parkinson’s Disease Quality of Life; T, normally distributed score with a mean of 50 and SD of 10, corrected for age and education; UPDRS, Unified Parkinson’s Disease Rating Scale.
Significant changes in cognitive test scores (compared with baseline) are printed in bold typeface.
Stimulation parameters
Contacts, right/left monopolar		1-/1-2-	1-/1-2-	1-/1-2	Off	3-/2-3-	3-/2-3-
Amplitude (V) right/left		3.2/2.5	3.2/2.5	3.2/2.5		2.6/2.5	2.6/2.5
Pulse width (μs)		60	60	60		60	60
Frequency (Hz)		185	185	185		130	130
UPDRS-III (off/on)	56/34	21/13	21/13	/14		22/	/18
H&Y (off/on)	3/3	3/2,5	3/2,5	/2,5		3/	/2
Medication
Pergolide (mg)	6–8	4	3	2	2	2	0
LEU	880	750	510	760	760	760	560
Executive function
Category fluency (T)	47	43	44	37	46	33	35
COWAT letter fluency (T)	52	51	50	55	56	60	63
Stroop colour–word (T)	39	33	44	34	28	32	37
Trailmaking B (T)	49	51	60	42	47	44	56
PASAT number correct	47	33	25	29	39	38	38
Memory
AVLT immediate recall (T)	51	37	38	37	33	37	45
AVLT delayed recall (T)	46	30	34	31	35	35	39
Decision-making
IGT disadvantageous choices%				34	56	78	70
Go/no go commission errors%				48	43	68	77
Questionnaires
DEX Questionnaire self/proxy	11/23	10/29	6/22	15/42	11/56	9/50	10/28
PDQL	87	71	70	66		66	70
MADRS	8	9	3	7	9		9