Table 1.

Demographic data of the subjects

	PD-N (n = 255)	PD-MCI (n = 161)	PD-D (n = 78)	p value	Group comparison‡
Male/female, n	145/110	92/69	42/36	0.88*	PD-N = PD-MCI = PD-D
Age, yr	69.3 ± 7.5	70.5 ± 7.3	74.2 ± 6.3	< 0.001†	PD-N = PD-MCI < PD-D
Education, yr	9.3 ± 4.7	7.7 ± 5.4	8.3 ± 5.5	0.004†	PD-N > PD-MCI
Duration of PD, yr	3.6 ± 3.5	4.8 ± 4.5	6.7 ± 4.5	< 0.001†	PD-N = PD-MCI < PD-D
UPDRS motor score	23.7 ± 11.6	24.6 ± 11.9	32.3 ± 10.0	0.006†	PD-N = PD-MCI < PD-D
Hoehn & Yahr stage	1.9 ± 0.6	2.1 ± 0.6	2.7 ± 0.7	0.003†	PD-N = PD-MCI < PD-D
LED, mg/day	208 ± 363	430 ± 479	602 ± 352	0.027†	PD-N < PD-D
BDI score	14.1 ± 9.9	12.2 ± 9.0	18.1 ± 11.9	0.19†	PD-N = PD-MCI = PD-D

Data are expressed as the mean ± SD.

^*chi-square test,

^†ANOVA,

^‡by Bonferroni’s method.

PD: Parkinson’s disease, PD-N: Parkinson’s disease with normal cognition, PD-MCI: Parkinson’s disease with mild cognitive impairment, PD-D: Parkinson’s disease with dementia, UPDRS: Unified Parkinson’s Disease Rating Scale, LED: levodopa equivalent dose, BDI: Beck’s Depression Inventory.