Table 3.

Data of internal consistency of the preliminary MDS‐NMS in Parkinson's disease patients

	Cronbach's alpha	Inter‐item correlation	Item homogenity index	Item‐total correlation
A. Depression	0.91	0.41–0.57	0.67	0.73–0.84
B. Anxiety	0.85	0.37–0.68	0.59	0.53–0.82
C. Apathy	0.91	0.41–0.70	0.73	0.76–0.83
D. Psychosis	0.59	0.19–0.62	0.38	0.07–0.69
E. ICD & related disorders	0.42	‐0.04–0.56	0.17	0.04–0.48
F. Other NPS	0.61	‐0.06–0.59	0.25	0.19–0.76
G. Cognition	0.85	0.19–0.62	0.48	0.51–0.87
H. Orthostasis*	0.79	0.70	0.65	‐
I. Urinary	0.84	0.05–0.64	0.51	0.42–0.83
J. Sexual*	0.72	0.43	0.56	‐
K. Gastrointestinal	0.63	0.03–0.22	0.33	0.23–0.60
L. Thermoregulatory*	0.54	0.32	0.40	‐
M. Sleep & wakefulness	0.75	‐0.03–0.41	0.31	0.33–0.55
N. Pain	0.77	0.13–0.56	0.45	0.40–0.66
O. Others	0.49	‐0.01–0.41	0.26	0.04–0.43
P. Non‐motor fluctuations	0.93	0.10–0.80	0.64	0.68–0.85

Abbreviations: MDS‐NMS Movement Disorder Society Non‐Motor Symptoms scale.

^* Each of these domains has only two items.