. 2022 Feb 1;37(5):1064–1069. doi: 10.1002/mds.28933

TABLE 1.

Demographic, clinical characteristics and SNc measurements

Demographics	HVs	iRBD	PD	t test ^a (P value)
Demographics	HVs	iRBD	PD	HVs vs. PD	HVs vs. iRBD	iRBD vs. PD
No. of subjects	55	47	134
Age, y	61.4 ± 8.8	67.7 ± 5.0 ^b ^, ^c	61.6 ± 9.4	0.90	<0.001	<0.001
Male/Female	27/28	41/6 ^b ^, ^c	84/50	0.84	<0.001	0.001
Clinical characteristics
MMSE	29.4 ± 0.8	29.0 ± 1.0 ^d	29.0 ± 1.2 ^e	0.01	0.01	0.93
MDS‐UPDRS I	5.1 ± 3.4	8.9 ± 4.9 ^b	9.4 ± 3.9 ^f	<0.001	<0.001	0.53
MDS‐UPDRS II	1.2 ± 1.8	2.3 ± 2.2 ^b ^, ^c	8.1 ± 3.8 ^e	<0.001	0.00	<0.001
MDS‐UPDRS III off	5.7 ± 5.4	11.7 ± 6.5 ^b ^, ^c	29.5 ± 7.9 ^f	<0.001	<0.001	<0.001
MDS‐UPDRS IV	NA	NA	0.1 ± 0.7	NA	NA	NA
Hoehn and Yahr score	0.1 ± 0.5	0.7 ± 0.9 ^b ^, ^c	2.0 ± 0.3 ^f	<0.001	<0.001	<0.001

				GLM‐ANCOVA: group factor
SNc imaging measurements				HVs vs. PD vs. iRBD		HVs vs. PD		HVs vs. iRBD		iRBD vs. PD
Automated				F value	P value	F value	P value	F value	P value	F value	P value
Volume (mm³)	297.1 ± 55.1	240.3 ± 47.5 ^b ^, ^g	218.8 ± 51.0 ^f	44.32	<0.001	85.39	<0.001	29.85	<0.001	6.18	0.01
Corrected volume (C_vol)	0.21 ± 0.04	0.16 ± 0.04 ^b ^, ^g	0.15 ± 0.04 ^f	51.00	<0.001	99.29	<0.001	31.47	<0.001	8.16	0.00
SNR	110.1 ± 1.5	109.7 ± 1.9 ^c	108.4 ± 1.5 ^f	25.70	<0.001	47.27	<0.001	1.79	0.18	20.40	<0.001
CNR	1.58 ± 0.27	1.45 ± 0.34 ^d ^, ^g	1.30 ± 0.30 ^f	18.34	<0.001	37.74	<0.001	4.80	0.03	8.28	0.00
Manual
Volume (mm³)	261.8 ± 41.3	229.5 ± 26.3 ^b	217.9 ± 56.3 ^f	16.06	<0.001	27.50	<0.001	21.41	<0.001	1.82	0.17
Corrected volume (C_vol)	0.18 ± 0.03	0.16 ± 0.02 ^b	0.14 ± 0.04 ^f	21.74	<0.001	38.31	<0.001	20.61	<0.001	3.37	0.07
SNR	111.1 ± 1.5	110.7 ± 1.7 ^c	109.4 ± 1.6 ^f	25.75	<0.001	43.39	<0.001	1.68	0.20	21.38	<0.001
CNR	1.74 ± 0.28	1.60 ± 0.33 ^d ^, ^g	1.46 ± 0.34 ^f	16.05	<0.001	30.94	<0.001	5.20	0.02	6.76	0.01

Demographical and clinical characteristics were compared using t‐tests. Significant differences are considered at P value <0.05.Trends are indicated in italics. Data represented as mean ± standard deviation.

^{^a}

Sex was compared using χ².

^{^b}

For P value <0.001.

^{^c}

For P value <0.001.

^{^d}

Indicates significant difference between HVs and iRBD with P value <0.01.

^{^e}

Indicates significant difference between HVs and PD with P value <0.01.

^{^f}

For P value <0.001.

^{^g}

Indicates significant difference between iRBD and PD with P value <0.0.

Abbreviations: SNc, substantia nigra pars compacta; HVs, healthy volunteers; iRBD, isolated REM sleep behavior disorder; PD, Parkinson's disease; MMSE, Mini‐Mental State Examination; SNR, signal‐to‐noise ratio; CNR, contrast‐to‐noise ratio.