TABLE 2.

Relation between behavioral and autonomic measures for the whole sample (N = 136)

	NFCS	Sleep/waking state	Finger splay	Change in HR	Change in LF power	Change in HF power
Sleep/waking state	0.557†
Finger splay	0.233*	0.102
Change in HR	0.550†	0.508†	0.094
Change in LF power	−0.232*	−0.221*	−0.060	−0.360†
Change in HF power	−0.155	−0.152	−0.096	−0.330†	0.680†
LF/HF ratio	−0.111	−0.153	−0.012	−0.120	0.326†	−0.053

^*p <0.01.

^†p <0.001.

NFCS, Neonatal Facial Coding System; HR, heart rate; LF, low-frequency; HF, high-frequency.