Table 3.

Intraclass correlation coefficient (ICC) of gain and phase for first and second visit in eight subjects

Maneuver (n)	Gain						Phase
	‐CO 2			+CO 2			‐CO 2			+CO 2
	ICC	Lower bound	Upper bound	ICC	Lower bound	Upper bound	ICC	Lower bound	Upper bound	ICC	Lower bound	Upper bound
SinTilt (Hz)(8)
0.042	0.288	−0.250	0.774	0.407	−0.405	0.848	0	−0.524	0.629	0.318	−0.490	0.816
0.067	0.453*	−0.072	0.842	0.717*	0.105	0.936	0.348	−0.093	0.783	0.587	−0.132	0.901
0.1	0.804*	0.362	0.956	0.950*	0.791	0.990	0.333*	−0.024	0.757	0.679*	0.093	0.924
0.167	0.778*	0.277	0.950	0.751*	0.175	0.944	0.788*	0.293	0.953	0.815*	0.345	0.960
PB (Hz) (7)
0.1	0.616	−0.073	0.909	0.529	−0.241	0.885	0.380	−0.290	0.828	0.203	−0.681	0.780
0.167	0.042	−0.751	0.707	0	−0.984	0.597	0.738*	0.163	0.941	0.533	−0.236	0.887
0.25	0	−0.870	0.329	0	−1.307	0.409	0.275	−0.533	0.800	0	−0.902	0.649
Rest 0.1 Hz
Supine (8)	0.424	−0.325	0.836	0.585*	−0.027	0.886	0.320	−0.444	0.797	0.222	−0.580	0.761
HUT 30° (7)	0.145	−0.746	0.785	0.044	−0.904	0.755	0.142	−0.772	0.786	0	−1.037	0.659
HUT 70° (8)	0.641*	0.011	0.906	0.598*	−0.054	0.893	0.502*	−0.057	0.851	0.009	−0.574	0.625

Intraclass correlation coefficients (agreement) during sinusoidal tilt (eight subjects), paced breathing at 30° HUT (PB) (seven subjects) and resting recordings in three body positions (7–8 subjects) who participated a second time almost a year after the first. Values are calculated separately for gain and phase and for each of the stimulus frequencies during SinTilt, PB, and rest, respectively (*indicates P ≤ 0.05). Inclusion of the absolute P_ETCO₂ level during each stimulus as covariate in the ANOVA model increased ICC during SinTilt considerably. During PB only at 0.167 Hz and without P_ETCO₂ in the model, a significant ICC could be determined. In the resting recordings, only at HUT 70° significant ICC values were present in both gain and phase. Values of 0 indicate that no valid ANOVA model was found. (Lower‐ and upper bounds are the 95% confidence limits.)