Table 1. Overview of participantś baseline characteristics.

	Cntr	PD group		p-values
		non-DBS	DBS	Controls vs.non-DBS	Controls vs.DBS	non-DBS vs.DBS
	n = 19	n = 26	n = 21
		[n = 18]	[n = 19]
Characteristics
	M (± SD)	M (± SD)	M (± SD)
Age (years)	67.2 (±8.1)	67.3 (±8.2)	64.7 (±8.6)	.97	.35	.30
		[65.5 (±8.5)]	[65.2 (±8.0)]	[±.54]	[±.44]	[±.90]
Educ. (years)	10.7 (±1.9)	10.7 (±1.6)	10.2 (±1.5)	.88	.36	.38
		[10.8 (±1.7)]	[10.4 (±1.5)]	[±.38]	[±1.00]	[±.38]
Gender (f/m)	7/12	13/13	4/17	.38	.21	.03
		[9/9]	[4/15]	[±.42]	[±.28]	[±.07]
Handedness (r/l)	16/3	24/2	20/1	.39	.25	0.68
		[16/2]	[18/1]	[±.68]	[±.29]	[±.52]
net PANDA	19.5 (±3.1)	18.0 (±3.1)	17.5 (±3.3)	.17	.06	.65
(points)		[18.6 (±3.6)]	[17.5 (±3.4)]	[±.33]	[±1.00]	[±.33]
Disease duration		11.2 (±6.2)	14.1 (±4.5)			.07
(years)		[14.5 (±4.0)]	[15.1 (±3.5)]			[±.63]
Side of onset		14/9/3	17/2/2			.11
(r/l/b)		[9/6/3]	[15/2/2]			[±.16]
LED (mg)		1147.4 (±755.6)	573.6 (±383.2)			.00
		[1341.9 (±788.1)]	[570.1 (±349.3)]			[±.00]
UPDRS III (points)		25.0 (±14.1)	19.8 (±7.1)			.13
		[27.2 (±15.5)]	[20.6 (±6.9)]			[±.10]
HY (stage)		2.1 (±.9)	2.6 (±.7)			.08
		[2.1 (±1.0)]	[2.6 (±.7)]			[.92]

HY: Hoehn & Yahr; net PANDA: Parkinson Neuropsychometric Dementia Assessment (PANDA) after subtraction of the test item Verbal Fluency (max. = 23 pt); f: female; m: male; r: right; l: left; b: bilaterally; LED: total daily levodopa equivalent dose; UPDRS III: Unified Parkinson’s Disease Rating Scale – motor score (max. = 108 pt).

Values indicate the mean (± standard deviation). Values in each upper row relate to each entire group of patients. Values in the lower rows, given in brackets, relate to the subgroup of long-term diseased patients. Disease related values refer to the treatment ON condition.