Spontaneous K-Complex Density in Slow-Wave Sleep.

To study spontaneous K-complex (KC) densities during slow-wave sleep. The secondary objective was to estimate intra-non-rapid eye movement (NREM) sleep differences in KC density.It is a retrospective study using EEG data included in polysomnographic records from the archive at the sleep research laboratory of the Centre for Physiotherapy and Rehabilitation Sciences, Jamia Millia Islamia, India. The EEG records of 4459 minutes were used. The study presents a manual identification investigation of KCs in 17 healthy young adult male volunteers (age = 23.82±3.40 years and BMI = 23.42±4.18 kg/m2).N3 had a higher KC density than N2 (Z = -2.485, p = 0.013) for all of the probes taken together. Four EEG probes had a higher probe-specific KC density during N3. The inter-probe KC density differed significantly during N2 (χ2 = 67.91, p < .001), N3 (χ2 = 70.62, p < .001) and NREM (χ2 = 68.50, p < .001). The percent distribution of KC decreased uniformly with sleep cycles.The inter-probe differences during N3 establish the fronto-central dominance of the KC density regardless of sleep stage. This finding supports one local theory of KC generation. The significantly higher KC density during N3 may imply that the neuro-anatomical origin of slow-wave activity and KC is the same. This temporal alignment with slow-wave activity supports the sleep-promoting function of the KC

Effects of vitamin D supplementation in infancy on growth, bone parameters, body composition and gross motor development at age 3-6 years: follow-up of a randomized controlled trial.

BACKGROUND: The long-term effects of infant vitamin D supplementation and status are unclear since there have been few controlled intervention trials and these have been small and contradictory. The Delhi Infant Vitamin D Supplementation (DIVIDS) trial found that supplementation of low-birthweight term infants with one recommended dietary allowance of vitamin D from 1 week to 6 months of age resulted in increased length and weight at 6 months. In the DIVIDS-2 study we followed up the DIVIDS children, now aged 3-6 years, to determine longer-term effects. METHODS: DIVIDS children, 446 from the vitamin D arm and 466 from the placebo arm, attended the follow-up visit. Data collection included anthropometry, blood pressure, bone structure and strength by quantitative ultrasound (QUS), gross motor tests, deuterium dilution test of body composition on a subset (n = 229) and blood samples for measurement of vitamin D status. RESULTS: Body mass index Z scores (BMIZ) were lower (adjusted P = 0.003)in the vitamin D Group [-1.18 (SD 0.92)] when compared with the placebo [-1.02 (SD 0.91)] group as a result of slightly lower weight and slightly greater height. The vitamin D group also had lower thigh circumference and arm muscle area and borderline lower mid-upper arm circumference. There were no group differences in body fat percentage, bone QUS or blood pressure and few differences in motor development measures. CONCLUSIONS: Vitamin D supplementation of low-birthweight infants in infancy resulted in children being thinner at age 3-6 years but in no differences in functional outcomes

Inter-sleep stage differences in K-complex density at each EEG probe.

<p>Inter-sleep stage differences in K-complex density at each EEG probe.</p

Probe-specific K-complex densities.

<p>Probe-specific K-complex densities.</p

Inter-probe differences in K-complex densities during each sleep stage(s).

<p>Inter-probe differences in K-complex densities during each sleep stage(s).</p

Trend of probe-specific K-complex numbers across sleep cycles.

<p>Each panel represents the probe-specific K-complexes across different cycles. The Y-axis shows the means and standard deviations of absolute numbers of K-complexes. The X-axis shows the first four cycles of the sleep stages.</p