Table 2.

Comparison of demographic data and abnormality in nigrosome 1 and nigrosome 4 between early‐stage IPD and late‐stage IPD

Per patient analysis		Early‐stage IPD patients (n = 89)	Late‐stage IPD patients (n = 39)	Cohen's d	P value
Age		68.0 [62.−74.0]a	75.0 [67.0–79.0]a	0.70	0.001b
Gender (female, %)		48 (53.9%)	19 (48.7%)	Not applicable	0.587c
Onset age (year)		67.0 [59.0–73.0]a	72.0 [64.0–77.5]a	0.43	0.017
Disease duration (months)		12.0 [4.0–13.0]a	24.0 [6.5–51.0]a	0.67	0.002
UPDRS I		1.0 [1.0–4.0]a	4.0 [2.0–7.0]a	0.90	<0.0001b
UPDRS II		6.0 [4.0–8.0]a	14.0 [10.0–18.0]a	1.59	<0.0001b
UPDRS III		15.0 [12–19.0]a	29.0 [23–38.5]a	1.66	<0.0001b
Both nigrosome 1 and 4 affected in both SNs	No	72 (80.9%)	15 (38.5%)		<0.0001c
	Yes	17 (19.1%)	24 (61.5%)

Per substantia nigra analysis		Substantia nigra of early‐stage IPD (n = 178)	Substantia nigra of late‐stage IPD (n = 78)		P value
Nigrosome 1 only affected		116 (65.2%)	20 (25.6%)		<0.0001c
Both nigrosome 1 and 4 affected		62 (34.8%)	58 (74.4%)
Nigrosome 1 affected with or without nigrosome 4 affected		161 (90.4%)	78 (100%)		0.005c
Both nigrosome 1 and 4 intact		17 (9.6%)	0 (0%)

^aData are median [interquartile range].

^bMann‐Whitney U test.

^cChi‐square test.