Table 3.

Correlation analysis between the total score of nonmotor symptoms assessed by the MDS-UPDRS Part I and variables.

Variable	Correlation coefficient ρ a	p value
Age	0.192	0.002
Disease onset age	0.005	0.940
Duration of disease	0.278	<0.001
HY	0.457	<0.001
SE-ADL	−0.524	<0.001
BDI	0.621	<0.001
MMSE	−0.243	<0.001
PDQ-39 SI	0.617	<0.001
MDS-UPDRS II	0.579	<0.001
MDS-UPDRS III	0.364	<0.001
MDS-UPDRS IV	0.160	0.009
Duration of levodopa therapy	0.285	<0.001
Daily dose of levodopa	0.300	<0.001

^aSpearman rank coefficient.

HY, Hoehn and Yahr stage; SE-ADL, Schwab and England Activities of Daily Living Scale; BDI, Beck Depression Inventory; MMSE, Minimental State Examination; PDQ-39 SI, Parkinson's Disease Questionnaire Summary Index; MDS-UPDRS, Movement Disorders Society's Unified Parkinson's Disease Rating Scale.