TABLE 3.

Comparison of cardiac baroreflex, and cardio-postural coupling between healthy controls and Parkinson’s disease patients during supine, tilt, and standing positions. Table lists mean ± SD of gain, active gain (AG), fraction time active (FTA), and causality values. The Bolded values indicate a significant difference (Wilcoxon rank sum test) between Parkinson’s patients (PD) and healthy controls (HC). *, § represent a significant difference (post-hoc analysis with Bonferroni adjustment) from supine, tilt, respectively.

Cardiac baroreflex and effect of heart on BP	Supine		Tilt		Standing
	HC	PD	HC	PD	HC	PD
$\text{SBP}\to \text{ RR}$ gain	8.37 ± 3.76	8.41 ± 5.16	5.78 ± 3.71*	3.69 ± 1.57*	3.28 ± 2.01*§	2.88 ± 1.30*
$\text{SBP }\to \text{RR}$ FTA	0.42 ± 0.20	0.23 ± 0.18	0.42 ± 0.24	0.23 ± 0.19	0.48 ± 0.25	0.29 ±0.24
$\text{SBP }\to \text{ RR}$ AG	3.58 ± 2.40	1.85 ± 1.73	2.16 ± 1.61*	0.98 ± 0.94	1.78 ± 1.61*	0.95 ± 0.93*
$\text{SBP}\to \text{ RR}$ causality	0.97 ± 0.04	0.95 ± 0.07	0.98 ± 0.02	0.94 ± 0.07	0.96 ± 0.04	0.91 ± 0.14
$\text{RR}\to \text{ SBP}$ causality	0.98 ± 0.02	0.97 ± 0.03	0.98 ± 0.02	0.95 ± 0.04*	0.98 ± 0.02	0.95 ± 0.05
Cardio-postural coupling and muscle-pump
$\text{SBP}\to {\text{ EMG}}_{\text{imp}}$ gain	0.65 ± 1.14	0.96 ± 0.65	1.11 ± 1.29	1.97 ± 2.06*	1.61 ± 1.07*§	3.15 ± 1.83*§
$\text{SBP}\to {\text{ EMG}}_{\text{imp}}$ FTA	0.16 ± 0.15	0.06 ± 0.05	0.12 ± 0.13	0.06 ± 0.06	0.09 ± 0.09	0.04 ± 0.04
$\text{SBP}\to {\text{EMG}}_{\text{imp}}$ AG	0.06 ± 0.08	0.05 ± 0.05	0.08 ± 0.08	0.07±0.06	0.13 ± 0.11*	0.13 ± 0.13*
$\text{SBP}\to {\text{EMG}}_{\text{imp}}$ causality	0.94 ± 0.03	0.94 ± 0.04	0.96 ± 0.04*	0.95 ± 0.02	0.91 ± 0.05*§	0.91 ± 0.05*§
${\text{EMG}}_{\text{imp}}\to \text{SBP}$ causality	0.99 ± 0.02	0.96 ± 0.07	0.98 ± 0.02	0.96 ± 0.03	0.98 ± 0.03	0.95 ± 0.04