[Show abstract][Hide abstract] ABSTRACT: This study characterises and describes the maturational evolution of the healthy infant sleep electroencephalogram (EEG) longitudinally from 2 weeks to 24 months of age, by means of power spectral analysis.
A prospective cohort of 34 healthy infants underwent overnight polysomnography (PSG) at 2 weeks, and at 3, 6, 12 and 24 months of age. Sleep epochs were scored as Active Sleep (AS) and Quiet Sleep (QS) at 2 weeks of age and as Rapid Eye Movement (REM) and Non-REM (NREM) stages from 3 months onwards. Representative epochs were used to generate the EEG power spectra, from the central C3 derivation. These were analysed visually and quantitatively in AS/REM and QS/NREM sleep in the following bandwidths: delta (0.5-4 Hz); theta (4-8 Hz); alpha (8-11 Hz); sigma (11-15 Hz) and 0.5-25 Hz.
Sleep EEG (central derivation) power spectra changed significantly in the different bandwidths as the infants matured. The emergence of a peak in the sigma bandwidth in NREM N2 sleep corresponded with the development of sleep spindles. Maturational changes were also seen in NREM N3 and in theta and alpha bandwidths in both AS/REM and QS/NREM.
Sleep EEG power spectra characteristics in healthy infants evolve in keeping with maturation and neurodevelopmental milestones.
This study provides an atlas of healthy infant sleep EEG in the early years of life, providing a basis for association with other neurodevelopmental measures and a normative dataset on which disease may be discriminated.
Clinical neurophysiology: official journal of the International Federation of Clinical Neurophysiology 02/2011; 122(2):236-43. DOI:10.1016/j.clinph.2010.06.030 · 3.10 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Background Children with Prader–Willi syndrome (PWS) are known to have sleep-disordered breathing. In addition to hypersomnolence and obstructive sleep apnoea, central respiratory control abnormalities may be present from infancy. The aims of this study were to describe breathing patterns in infants with PWS, and the effects of supplemental oxygen in this group.
Methods Children with PWS attending a tertiary sleep clinic underwent full polysomnographic studies either to investigate persisting neonatal oxygen requirement, or as screening for sleep-disordered breathing. Continuous oxygen saturations (SpO2) and transcutaneous carbon dioxide (tcCO2) were recorded. Central and obstructive events were defined in accordance with the American Academy of Sleep Medicine (AASM) 2007 scoring rules. Children who had significant hypoxia associated with central events were started on supplemental oxygen during sleep and followed at 3-monthly intervals with split-night studies (periods in both air and supplemental oxygen). Paired t-tests were used to compare sleep data in air and oxygen arms for our subject cohort.
Results 30 split-night studies were undertaken on 10 infants (8 female) aged 0.06–1.79 (mean 0.79, SD 0.44) years. At baseline (ie, air), children with PWS had a mean (SD) central apnoea index (CAI) of 6.9 (6.3) per hour, with accompanying falls in SpO2. Oxygen therapy led to statistically significant reductions in CAI, as well as improved SpO2 (Abstract P198 Table 1). No significant change in the number of obstructive events was noted.
Discussion Infants with PWS have sleep-disordered breathing problems, which are predominantly central in origin, and cause significant hypoxia in some patients. Improvements in both central event indices and oxygenation were noted on oxygen therapy. Longitudinal work with this patient group would help to establish timing of onset of obstructive symptoms. Whether early recognition of central hypoventilation, and correction with oxygen alter the evolution of respiratory dysfunction and excessive daytime somnolence in later life remains to be seen.
[Show abstract][Hide abstract] ABSTRACT: Pulse transit time (PTT) is a non-invasive measure, defined as time taken for the pulse pressure waves to travel from the R-wave of electrocardiogram to a selected peripheral site. Baseline PTT value is known to be influenced by physiologic variables like heart rate (HR), blood pressure (BP) and arterial compliance (AC). However, few quantitative data are available describing the factors which can influence PTT measurements in a child during breathing. The aim of this study was to investigate the effects of changes in breathing efforts on PTT baseline and fluctuations. Two different inspiratory resistive loading (IRL) devices were used to simulate loaded breathing in order to induce these effects. It is known that HR can influence the normative PTT value however the effect of HR variability (HRV) is not well-studied. Two groups of 3 healthy children (≤12years) were recruited; one group with insignificant (p>0.05) HR changes during all test activities. Results showed that HRV is not the sole contributor to PTT variations and suggest that changes in other physiologic parameters are also equally important. Hence, monitoring PTT measurement can be indicative of these associated changes during tidal or increased breathing efforts in healthy children.
Conference proceedings: ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference 01/2005; 7:7521-4. DOI:10.1109/IEMBS.2005.1616252
[Show abstract][Hide abstract] ABSTRACT: The prevalence of sudden infant death syndrome (SIDS) has been well studied and central sleep apnea is deemed as one of the possible causes. Current gold standard for its diagnosis is nocturnal polysomnography (PSG). However, this procedure is complex and generally needs to be performed in a sleep laboratory. Pulse transit time (PTT) shows its potential to indicate abrupt blood pressure (BP) changes during the occurrences of upper airway obstruction. The main objective of this study was to assess the capability of PTT to differentiate central respiratory events from tidal breathing in infants. This study involved 5 infants (4 male) with mean age of 7.8 months. 50 valid central respiratory events were randomly selected. These events were free from motion artifacts and pre-scored in the corresponding PSG studies by two blinded observers. PTT measurements from these events were then evaluated against the PSG scorings. Using a two-tailed F-test for variance, it was observed that central events differed from tidal breathing in a significant manner (p<0.05). Furthermore, PTT has showed its sensitivity to monitor marginal BP fluctuations during tidal breathing. Hence, the results herein suggest that PTT can be a valuable non-invasive technique to monitor central apneic events in sleeping infants.
Conference proceedings: ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference 01/2005; 3:2579-82. DOI:10.1109/IEMBS.2005.1616996