Objectives: 

To investigate EEG and heart rate (HR) beat-to-beat oscillations associated with cardiovascular Mayer-Traube-Hering waves (MTH) and respiratory sinus arrhythmia control, in a group of full term neonates at risk (sudden infant death syndrome (SIDS)´ siblings).

Materials: 

Groups (GG): one control group (CG) of 18 healthy neonates: 9 (C1) ranging 45-50 weeks of postmenstrual age (PMA) and 9 (C2) within 51-56 PMA and one SIDS siblings group (SG) of 15: 9 (S1) within 45-50 and 6 (S2) within 51-56 PMA. Data: four EEG monopolar channels (C4/O2/C3/O1vs. A1/A2 references) and the ECG and respiratory signal. Signals were recorded simultaneously during quiet (QS) and active (AS) sleep stages (SS) and resampled at 500 Hz. Two 8 minutes artefact-free signal-segments were selected from each subject and six beat-to-beat variability signals were obtained by computing sequentially: the RR cardiac period (VRR), the EEG variance of each channel (4 VEEG) and the mean respiratory amplitude (VRP). Power-spectra of variability signals and coherence between them (after surrogate-test) were calculated. Results were restricted to frequency bands (Hz) 0.05-0.15 (LF-MTH range) and 0.30-0.70 (HF, respiratory frequency range). Statistics: Factorial ANOVA and Bonferroni pot-hoc comparisons.

Results: 

HF band: VRR relative power and VEEG-C4 absolute power presented significant GG*PMA*SS interactions (F(1,60)=3.98, P<0.05 and F(1,60)=10.11,P<0.01 respectively); VRR power was greater for C1 than for S1 during QS (P<0.001); VEEG-C4 power was greater for S2 than for C2 in QS (P<0.001); VRR-VRP coherence was significant (P<0.05) and was lower for the SG (P<0.05) independently of PMA and SS. LF band: GG*PMA*SS interactions only existed for VEEG-C4 (F(1,60)=6.53, P<0.01) this power was greater for S2 than for C2 during QS (P<0.001).

Conclusions: 

In neonates at risk the power of beat-to-beat variability signals (EEG and HR) and the coherence between them exhibited alterations in their respiratory and cardiovascular oscillations.