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 5

Coefficients and their standard errors (SE) of the optimized multilevel model with the additional between-subject centering effect (Model #2) 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)
β₀	−0.098 (0.079)^NS	−0.012 (0.017)^NS	0.104 (0.028)	−0.060 (0.047)^NS	−0.018 (0.034)^NS	0.131 (0.030)
	0.973 (0.011)	0.884 (0.020)	0.993 (0.007)	0.979 (0.011)	0.936 (0.012)	0.923 (0.011)
β_wake	Baseline	Baseline	Baseline	Baseline	Baseline	Baseline
β_REM	0.002 (0.008)^NS	−0.199 (0.025)	−0.027 (0.004)	−0.104 (0.027)	0.030 (0.007)	−0.037 (0.007)
β_light	−0.035 (0.008)	−0.606 (0.026)	−0.062 (0.004)	−0.052 (0.020)	−0.027 (0.005)	0.039 (0.006)
β_deep	−0.044 (0.010)	−0.992 (0.033)	−0.054 (0.004)	−0.248 (0.026)	−0.096 (0.008)	0.105 (0.008)
		−0.002 (0.001)	−0.0001 (0.5e − 4)		0.0004 (0.0001)	0.0002 (0.0001)
	−0.024 (0.012)
					0.005 (0.001)	−0.004 (0.001)
		0.0003 (0.0001)	−0.0001 (0.2e − 4)	0.001 (0.0001)	0.0004 (0.0001)	−0.0004 (0.0001)
				−1.0e − 5 (0.1e − 5)
	0.0001 (0.5e − 4)
					−1.8e − 5 (0.5e − 5)	1.7e − 5 (0.5e − 5)

Random	Coefficient (SE)
Ω₀
Ω_wake	0.012 (0.001)	0.093 (0.011)	0.004 (0.0004)	0.094 (0.011)	0.006 (0.001)	0.005 (0.001)
Ω_REM	0.014 (0.002)	0.099 (0.011)	0.003 (0.0003)	0.095 (0.011)	0.007 (0.001)	0.006 (0.001)
Ω_light	0.006 (0.001)	0.061 (0.007)	0.002 (0.0003)	0.044 (0.005)	0.004 (0.001)	0.003 (0.0004)
Ω_deep	0.010 (0.001)	0.131 (0.015)	0.003 (0.0003)	0.087 (0.010)	0.006 (0.001)	0.006 (0.001)
	1.1e − 7 (0.1e − 7)	6.7e − 7 (0.8e − 7)	3.5e − 8 (0.4e − 8)	7.1e − 7 (0.8e − 7)	4.8e − 8 (0.6e − 8)	4.3e − 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	−151084	216873	−398866	185774	−75617	−74903

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.