TABLE 2.

Correlation between cognitive function, Parkinson’s disease severity and plasma biomarkers.

	α-synuclein	Aβ1-40	Aβ1-42	T-Tau
Cognitive test
Mini-Mental State Examination	−0.283**	0.263*	–0.159	−0.213*
Clinical Dementia Rating	0.411**	−0.355**	0.337**	0.298**
Clinical Dementia Rating sum of box	0.384**	−0.345**	0.250*	0.325**
Parkinson’s disease severity
Modified Hoehn and Yahr scale, mean (S.D.)	0.620**	−0.477**	0.331*	0.545**
UPDRS I, mean (S.D.)	0.274*	−0.360**	0.150	0.228*
UPDRS II, mean (S.D.)	0.417**	−0.411**	0.213*	0.281**
UPDRS III, mean (S.D.)	0.390**	−0.419**	0.217*	0.289**
UPDRS total, mean (S.D.)	0.399**	−0.427**	0.217*	0.292**
TRODAT
Right visual grading	0.003	−0.315*	0.134	–0.170
Left visual grading	0.012	–0.295	0.049	–0.088
Right SUR ratio	–0.110	−0.321*	0.192	0.223
Left SUR ratio	–0.140	–0.273	0.140	0.127
Mean ratio	–0.130	–0.308	0.173	0.182

UPDRS = The Unified Parkinson’s Disease Rating Scale, SUR = striatal uptake ratio, CDR = Clinical Dementia Rating, MMSE = Mini-Mental State Examination, Spearman rank correlation analysis to determine relationship between plasma biomarkers and cognitive test, Parkinson’s disease severity and TRODAT. ** = p < 0.01; * = p < 0.05.