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

Table 1 Measurement and definition of variables

Variable	Measurement	Characteristics
Sociodemographic factors	Age	Continuous variable
	Gender	Male or female
	Education	Middle school graduate and below or high school graduate and above
	Mainly used hand	Left hand, right hand, or both hands
	Family dementia history	Yes or No
	Family PD history	Yes or No
Environmental factors	Exposure to pesticide	Never, currently not exposed but exposed previously, or currently exposed to pesticide
Health behaviors	Pack-years	Non-smoking, 1-20, 21-40, 41-60, or ≥ 61 pack-years
	Coffee-drinking	Yes or No
	Mean coffee intake per day (cups/d)	No, ≤ 1, 2-3, or ≥ 4 cups
	Coffee drinking period (yr)	No, ≤ 5, 6-9, or ≥ 10
Disease history	Carbon monoxide poisoning	Yes or No
	Manganese poisoning	Yes or No
	Encephalitis	Yes or No
	Traumatic brain injury	Yes or No
	Stroke	Yes or No
	Alcoholism	Yes or No
	Diabetes	Yes or No
	Hypertension	Yes or No
	Hyperlipidemia	Yes or No
	Atrial fibrillation	Yes or No
Neuropsychological characteristics	Total score of KMMSE	Continuous variable
	Total score of KMoCA
	Global CDR score
	Sum of boxes in CDR
	K-IADL
	Total score of UPDRS
	Motor score of UPDRS
	H&Y staging
	Schwab & England ADL
Sleep behavior disorders	REM sleep behavior disorders	Yes or No
Exercise characteristics related to PD (PD related motor signs)	Tremor	Yes or No
	Rigidity	Yes or No
	Bradykinesia	Yes or No
	Postural instability	Yes or No
	LMC	Yes or No

PD: Parkinson’s disease; KMMSE: Korean Mini Mental State Examination; KMoCA: 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 scale; REM: Rapid eye movement; LMC: Late motor complications.