Table 1.

Prevalence and index of sighs in N3 sleep and REM sleep in participants with multiple system atrophy (MSA), Parkinson’s disease (PD), isolated REM sleep behavior disorder (iRBD), and controls

	MSA	PD	iRBD	Controls	P value	Post-hoc test
	A	B	C	D
Number	73	257	111	115	–	–
Stage N3
Participants with sighs, N (%)	57 (78)	130 (51)	73 (65.7)	79 (68)	<0.001	A = C = D > B
Sigh index/h of N3	2.75 (2.40)	0.93 (1.37)	1.18 (1.46)	1.06 (1.14)	<0.001	A > B = C = D
Range	0–15.9	0–6.5	0–6.4	0–4.7
Stage REM
Participants with sighs, N (%)	24 (32.9)	38 (14.8)	28 (25.2)	9 (7.83)	<0.001	A = C > B = D
Sigh index/h of REM	0.8 (1.6)	0.33 (1.2)	0.26 (0.55)	0.08 (0.34)	<0.001	A = B > C = D
Range	0–6.8	0–12.9	0–3.2	0–2.55