Table 2.

Autonomic testing results

	iRBD (n = 25)	PD (n = 28)	Controls (n = 18)	P	Pairwise comparisons
Sympathetic cholinergic (sudomotor) function
QSART volume forearm	1.19 [0.93,1.81]	0.76 [0.36,1.06]	0.71 [0.42,1.01]	0.011	n/a
QSART volume proximal leg	0.64 [0.41,1]	0.91 [0.38,1.47]	0.97 [0.86,1.47]	0.041	n/a
QSART volume distal leg	0.55 [0.36,0.8]	0.57 [0.38,1.28]	1.13 [0.61,1.51]	0.079	n/a
QSART volume foot	0.41 [0.15,0.62]	0.49 [0.19,1.12]	1.11 [0.61,1.3]	0.015	n/a
Cardiovagal function
E:I ratio	1.15 [1.09,1.2]	1.13 [1.08,1.23]	1.28 [1.19,1.36]	3.72 × 10−3	n/a
Valsalva ratio	1.45 ± 0.26	1.37 ± 0.14	1.49 ± 0.16	0.20	n/a
Sympathetic adrenergic function
Valsalva baseline to P2 minimum (mmHg)	−31 [−49, −17.75]	−28 [−39.5, −21.75]	−20 [−24.5, −16]	0.013	n/a
Valsalva P2 recovery (mmHg)	8.42 ± 12.3	−21.32 ± 16.04	−2.75 ± 6.48	6.32 ×10−11	PD < Ctrl < iRBD
Valsalva P4 overshoot (mmHg)	11.21 ± 10.28	−2.36 ± 18.97	14.94 ± 8.02	1.10 ×10−3	PD < Ctrl
Tilt baseline SBP (mmHg)	143.32 ± 11.16	135.04 ± 16.4	127.5 ± 10.42	1.77 ×10−3	Ctrl < iRBD
Tilt baseline HR (bpm)	63 [60,68]	67.5 [61,75]	63 [61.7,70]	0.27	n/a
Tilt ΔSBP (mmHg)	−18 [−39, −5]	−20.5 [−31.25, −13]	−12.5 [−14.75, −8]	0.049	n/a
CASS scores
CASS sudomotor	0 [0–1.25]	0 [0–1.25]	0 [0,0]	0.014	n/a
CASS cardiovagal	1 [0–2]	1 [0–1.25]	0 [0–1]	0.064	n/a
CASS sympathetic	1.5 [0–3]	1 [1–3.25]	0 [0–1]	4.78 × 10−3	n/a
CASS total	3 [1–5]	2 [1–5]	1 [0–1.25]	8.68 ×10−4	Ctrl < PD, iRBD

Comparisons of continuous measures with Kruskal-Wallis test and categorical data with χ²/Fisher’s exact test. Group-wise differences that remained significant after Bonferroni correction for multiple comparisons (α = 0.0031) are bolded and italicized.

RBD, isolated REM sleep behavior disorder; PD, Parkinson’s disease; QSART, quantitative sudomotor axon reflex test; E:I, expiratory:inspiratory ratio; P2, phase 2 Valsalva; P4, phase 4 Valsalva; CASS, composite autonomic severity score.