[P2-144] Autonomic function in preterm period is associated with brain growth
[Introduction] Autonomic nervous activity is fundamentally important for adequate brain development in preterm period.
[Purpose] Investigate the relation between autonomic activity in preterm age and area of brain components in term age.
[Subjects] Preterm very low birth weight infants without obvious brain lesions who cared for in Oita University hospital from Nov 2012 to Oct 2015 were enrolled. Cases of periventricular leukomalasia were excluded. 22 cases with mean birth gestation 29w5d, weight 1126g, and head circumference 26.8 cm were investigated.
[Method] Two-hour heart rates were obtained every 2 weeks. We classified the baby’s behavioral state from simultaneous video recording. Heart rate variability (HRV) spectrum was analyzed using the MemCalc system. Autonomic functional indices examined were normalized low frequency; LFnu (LF/Total power) as sympathetic plus parasympathetic function and normalized high frequency; HFnu (HF/Total power) as parasympathetic function. The data on sleep state and in supine position were extracted for analysis. The area of brain components was measured at the level of foramen Monro in axial T2-weighted MRI scans. We measured the areas of whole brain, white matter and gray matter.
[Results] A significant positive correlation were found between white matter area and LFnu at 32-33w, 34-35w, 36-37w (P<0.01), and white matter area and HFnu at 34-35w (P<0.05 Spearman's rho). Gray matter area did not present any correlation to the autonomic activity.
[Conclusion] Active autonomic function in preterm age is associated with large white matter area in term age. LFnu would be a useful index for the evaluation of autonomic function in preterm period.
[Purpose] Investigate the relation between autonomic activity in preterm age and area of brain components in term age.
[Subjects] Preterm very low birth weight infants without obvious brain lesions who cared for in Oita University hospital from Nov 2012 to Oct 2015 were enrolled. Cases of periventricular leukomalasia were excluded. 22 cases with mean birth gestation 29w5d, weight 1126g, and head circumference 26.8 cm were investigated.
[Method] Two-hour heart rates were obtained every 2 weeks. We classified the baby’s behavioral state from simultaneous video recording. Heart rate variability (HRV) spectrum was analyzed using the MemCalc system. Autonomic functional indices examined were normalized low frequency; LFnu (LF/Total power) as sympathetic plus parasympathetic function and normalized high frequency; HFnu (HF/Total power) as parasympathetic function. The data on sleep state and in supine position were extracted for analysis. The area of brain components was measured at the level of foramen Monro in axial T2-weighted MRI scans. We measured the areas of whole brain, white matter and gray matter.
[Results] A significant positive correlation were found between white matter area and LFnu at 32-33w, 34-35w, 36-37w (P<0.01), and white matter area and HFnu at 34-35w (P<0.05 Spearman's rho). Gray matter area did not present any correlation to the autonomic activity.
[Conclusion] Active autonomic function in preterm age is associated with large white matter area in term age. LFnu would be a useful index for the evaluation of autonomic function in preterm period.