[Pathological patterns in neonatal EEG before 30 weeks of gestational age]

Impact of prematurity on neurodevelopment

The consequences of prematurity on brain functional development are numerous and diverse, and impact all brain functions at different levels. Prematurity occurs between 22 and 36 weeks of gestation. This period is marked by extreme dynamics in the physiologic maturation, structural, and functional processes. These different processes appear sequentially or simultaneously. They are dependent on genetic and/or environmental factors. Disturbance of these processes or of the fine-tuning between them, when caring for premature children, is likely to induce disturbances in the structural and functional development of the immature neural networks. These will appear as impairments in learning skills progress and are likely to have a lasting impact on the development of children born prematurely. The level of severity depends on the initial alteration, whether structural or functional. In this chapter, after having briefly reviewed the neurodevelopmental, structural, and functional processes, we describe, in a nonexhaustive manner, the impact of prematurity on the different brain, motor, sensory, and cognitive functions.

Integrating neurocritical care approaches into neonatology: should all infants be treated equitably?

To improve the neurologic outcomes for infants with brain injury, neonatal providers are increasingly implementing neurocritical care approaches into clinical practice. Term infants with brain injury have been principal beneficiaries of neurologically-integrated care models to date, as evidenced by the widespread adoption of therapeutic hypothermia protocols for hypoxic-ischemic encephalopathy. Innovative therapeutic and diagnostic support for very low birth weight infants with brain injury has lagged behind. Given that concern for significant future neurodevelopmental impairment can lead to decisions to withdraw life supportive care at any gestational age, providing families with accurate prognostic information is essential for all infants. Current variable application of multidisciplinary neurocritical care approaches to infants at different gestational ages may be ethically problematic and reflect distinct perceptions of brain injury for infants born extremely premature.

Power spectral analysis of two-channel EEG in very premature infants undergoing heat loss prevention

OBJECTIVE

To evaluate whether wearing a wool cap, a routine practice used to prevent heat loss in premature infants, affects interpretation of electroencephalogram spectral analysis.

METHODS

Eighteen premature infants (median gestational age 28 weeks, range 23-32) without neurological complications were randomized to two channel (C3, C4 referred to Cz) digital electroencephalogram recordings with (90 min) and without (90 min) wearing wool cap, at 4 days of life. Electroencephalogram was analyzed automatically by measurement of burst suppression ratio and asymmetry index and by Fast Fourier Transform to calculate total absolute spectral power; relative spectral power in the δ (0.5-3.5 Hz), θ (4-7.5 Hz), α (8-12.5 Hz), and β (13-30 Hz) frequency bands; spectral edge frequency; and mean dominant frequency.

RESULTS

The use of wool cap had no effect on all electroencephalogram parameters considered. Gestational age showed an effect on relative spectral power of all considered bands, spectral edge frequency and mean dominant frequency, while no effect was seen on burst suppression ratio and asymmetry index. Neonates born at gestational weeks lower than 28 had significantly higher relative power in the δ band and lower relative power in the α and β bands.

CONCLUSIONS

Heat loss prevention using wool cap does not affect interpretation of spectral electroencephalogram. Spectral values in our group of very premature infants without neurological complications correspond to normal data reported in the literature. Maturation changes consist of reduction of relative power of the δ band, spectral edge frequency and mean dominant frequency.