Best early-onset Parkinson dementia predictor using ensemble learning among Parkinson's symptoms, rapid eye movement sleep disorder, and neuropsychological profile

Table 4 The normalized importance of variables in the random forest model

Variables	Mean decrease Gini
K-MMSE	7.224
K-MoCA	2.992
Sum of boxes in CDR score	2.872
Global CDR score	2.304
Motor UPDRS	2.104
K-IADL	1.720
Total UPDRS	1.587
Schwab & England ADL	1.258
H&Y staging	1.040
Late motor complications	0.775
Consumption of coffee	0.699
Education level	0.527
Pack year	0.505
BDI	0.409
Tremor	0.338
Postural instability	0.338
Rigidity	0.331
Gender	0.255
REM sleep behavior disorders	0.249
Hypertension	0.168
Handness	0.151
Diabetes	0.146
Hyperlipidemia	0.129
Carbon monoxide poisoning	0.124
Family PD history	0.074
Family dementia history	0.066
Bradykinesia	0.034
Manganese poisoning	0.013
Traumatic brain injury	0.002
Atrial fibrillation	< 0.001

K-MMSE: Korean Mini Mental State Examination; K-MoCA: Korean Montreal Cognitive Assessment; CDR: Clinical Dementia Rating; K-IADL: Korean Instrumental Activities of Daily Living; UPDRS: Score of Untitled Parkinson’s Disease Rating; H&Y staging: Hoehn and Yahr staging; Schwab & England ADL: Schwab & England Activities of Daily Living; PD: Parkinson’s disease; REM: Rapid eye movement; BDI: Beck Depression Inventory.