Table 1.

Demographic and clinical characteristics of all samples.

Variables	Study 1	Study 2	Study 3	Study 4	P value
	(n = 71)	(n = 45)	(n = 60)	(n = 60)	1 vs 2	1 vs 3	1 vs 4
Age, years	60.04 ± 10.60 (28–83)	64.47 ± 9.41 (45–81)	53.58 ± 10.93 (24–69)	60.67 ± 7.88 (48–75)	0.021	<0.001*	0.699
Sex, male/female	29/42	30/15	33/27	41/19	0.012*	0.150	0.003*
Duration, years	5.92 ± 5.33 (0.17–32)	6.24 ± 4.61 (0.67–23)	7.13 ± 4.96 (0–20)	0.58 ± 0.68 (0.03–2.66)	0.733	0.180	<0.001*
Education, years	8.75 ± 3.83 (0–16)	8.03 ± 4.52 (0–18)	9.47 ± 3.61 (0–16)	15.17 ± 2.99 (8–22)	0.378	0.273	<0.001*
UPDRS III	26.30 ± 14.27 (2–67)	27.04 ± 12.81 (7–70)	33.45 ± 16.47 (8–73)	22.22 ± 10.63 (6–51)	0.770	0.009*	0.064
H&Y stage	2.15 ± 0.74 (1–5)	2.41 ± 0.71 (1–4)	2.51 ± 0.94 (1–5)	1.73 ± 0.49 (1–3)	0.066	0.020	<0.001*
MoCA#	21.82 ± 5.33 (5–30)	20.87 ± 5.03 (10–29)	22.26 ± 5.54 (6–30)	26.88 ± 2.81 (15–30)	0.335	0.652	<0.001*
Mean FD	0.11 ± 0.04 (0.03–0.19)	0.31 ± 0.14 (0.10–0.66)	0.08 ± 0.04 (0.02–0.18)	0.13 ± 0.05 (0.05–0.25)	<0.001*	<0.001*	0.007*
LEDD#	673.83 ± 236.76 (225–1350)	690.71 ± 148.52 (332–1089)	404.08 ± 214.37 (0–947.63)	355.49 ± 189.85 (50–800)	0.638	<0.001*	<0.001*

Notes: Values of variables are presented as mean ± SD (range). Statistical differences are listed between Study 1 and Study 2 (1 vs 2), Study 1 and Study 3 (1 vs 3), and Study 1 and Study 4 (1 vs 4). Chi-square test was performed on the sex, and two-sample t-test was performed on other variables. * indicates for the Bonferroni-corrected P < 0.05. ^# indicates for partially missed scores (MoCA: for Study 3 n = 7; LEED: for Study 4 n = 21). UPDRS III Unified Parkinson’s Disease Rating Scale motor subsection, SD Standard deviation, FD Framewise displacement, H&Y Hoehn and Yahr, MoCA Montreal Cognitive Assessment, LEDD levodopa equivalent daily dose.