Computational Intelligence and Neuroscience

Research Article

Effects of Between- and Within-Subject Variability on Autonomic Cardiorespiratory Activity during Sleep and Their Limitations on Sleep Staging: A Multilevel Analysis

Table 4

Coefficients and their standard errors (SE) of the optimized multilevel model without the between-subject centering effect (Model #1) for the six cardiorespiratory parameters analyzed in this study.


Model coef.	Respiratory parameters		Cardiac parameters
Model coef.	BR, ln-Hz	SDBR, ln-Hz	HR, ln-bpm	SDNN, ln-ms	LF, nu	HF, nu

Fixed	Coefficient (SE)
	−1.458 (0.087)	−3.320 (0.032)	4.221 (0.016)	4.823 (0.255)	0.464 (0.014)	0.535 (0.027)
	Baseline	Baseline	Baseline	Baseline	Baseline	Baseline
β_REM	0.002 (0.008)^NS	−0.205 (0.026)	−0.028 (0.001)	−0.104 (0.027)	0.030 (0.007)	−0.037 (0.007)
β_light	−0.035 (0.008)	−0.611 (0.026)	−0.061 (0.001)	−0.052 (0.021)	−0.027 (0.006)	0.039 (0.006)
β_deep	−0.044 (0.010)	−0.997 (0.033)	−0.055 (0.001)	−0.249 (0.026)	−0.096 (0.008)	0.106 (0.008)
				−0.009 (0.002)		−0.002 (0.001)
			0.042 (0.021)	−0.247 (0.069)	−0.045 (0.018)	0.052 (0.017)
	0.011 (0.004)			−0.025 (0.011)
		0.001 (0.0004)	−0.0001 (0.2e − 4)	0.001 (0.0002)	0.0004 (0.0001)	−0.0004 (0.0001)
				−1.0e − 5 (0.3e − 5)

		−2.8e − 5 (1.3e − 5)			−1.7e − 5 (0.5e − 5)	1.7e − 5 (0.5e − 5)

Random	Coefficient (SE)
Ω₀
Ω_wake	0.030 (0.003)	0.159 (0.018)	0.018 (0.002)	0.224 (0.025)	0.018 (0.002)	0.014 (0.002)
Ω_REM	0.029 (0.003)	0.171 (0.020)	0.019 (0.002)	0.280 (0.031)	0.022 (0.002)	0.018 (0.002)
Ω_light	0.030 (0.003)	0.219 (0.024)	0.020 (0.002)	0.256 (0.028)	0.019 (0.002)	0.017 (0.002)
Ω_deep	0.031 (0.003)	0.257 (0.029)	0.020 (0.002)	0.324 (0.036)	0.020 (0.002)	0.017 (0.002)
	1.2e − 7 (0.1e − 7)	6.6e − 7 (0.8e − 7)	3.5e − 8 (0.4e − 8)	7.2e − 7 (0.8e − 7)	5.0e − 8 (0.6e − 8)	4.6e − 8 (0.5e − 8)

Residual
	0.019 (0.0001)	0.290 (0.001)	0.003 (0.00001)	0.230 (0.001)	0.033 (0.0001)	0.033 (0.0001)

Deviance	−150487	217253	−398075	186380	−75029	−74306

Note: ln, natural logarithm; nu, normalized unit; NS, not significant. The statistically significant effects (Wald -test, ), the fixed constant intercept , and sleep stage intercepts are presented.