Louise O'Brien

Polysomnographic Characteristics in Normal Preschool and Early School-Aged Children

OBJECTIVE. The objective of this study was to describe overnight polysomnographic measures in normal children aged 3 to 7 years. We conducted a retrospective analysis of normal polysomnographic evaluations from participants in 2 large community-based studies of sleep-disordered breathing among preschoolers and early school-aged children at Kosair Children’s Hospital Sleep Medicine Research Center at the University of Louisville. Participants included 542 healthy children with ages ranging from 3.2 to 8.6 years. RESULTS. Subjects were excluded from analysis if they had documented snoring during polysomnography, an obstructive apnea-hypopnea index of ≥1.0, or a periodic leg-movement index of ≥5.0. Because the greatest differences in polysomnography occurred between ages 5 and 6 years, analyses were performed for children 3 to 5 years and for ages ≥6. Sleep cyclicity was distinct between age groups, with both showing an initial brief rapid-eye-movement period, which lengthened across the night, but only the older group showing a decrease in cycle length across the night. Average obstructive apnea indices were 0.03 per hour of total sleep time (TST) for 3- to 5-year-old children and 0.05 per hour of TST for ≥6-year-old children, whereas central apnea indices were 0.82 and 0.45 per hour of TST, respectively. Older children spent a greater percentage of sleep time supine, and the apnea-hypopnea index differed according to body position. Twenty percent of all subjects had end tidal carbon dioxide values of >45 mm Hg, and 2.2% had recorded values >50 mm Hg during ≥50% TST. High variance was present on all measures. CONCLUSIONS. Developmental changes occur in several polysomnographic measures among normal children from 3 to 7 years of age, particularly during transition from preschool to early school age. Our findings in a large number of healthy community children comprise the most extensive compilation of normative reference values for laboratory-based pediatric polysomnography to date.

PHOX2B Genotype Allows for Prediction of Tumor Risk in Congenital Central Hypoventilation Syndrome

The Phox2b gene is necessary for autonomic nervous-system development. Phox2b-/- mice die in utero with absent autonomic nervous system circuits, since autonomic nervous system neurons either fail to form or degenerate. We first identified the Phox2b human ortholog, PHOX2B, as the gene underlying congenital central hypoventilation syndrome (CCHS, or Ondine curse), with an autosomal dominant mode of inheritance and de novo mutation at the first generation. We have subsequently shown that heterozygous mutations of PHOX2B may account for several combined or isolated disorders of autonomic nervous-system development--namely, tumors of the sympathetic nervous system (TSNS), such as neuroblastoma and late-onset central hypoventilation syndrome. Here, we report the clinical and molecular assessments of a cohort of 188 probands with CCHS, either isolated or associated with Hirschsprung disease and/or TSNS. The mutation-detection rate was 92.6% (174/188) in our series, and the most prevalent mutation was an in-frame duplication leading to an expansion of +5 to +13 alanines in the 20-alanine stretch at the carboxy terminal of the protein. Such findings suggest PHOX2B mutation screening as a simple and reliable tool for the diagnosis of CCHS, independent of the clinically variable phenotype. In addition, somatic mosaicism was detected in 4.5% of parents. Most interestingly, analysis of genotype-phenotype interactions strongly supports the contention that patients with CCHS who develop malignant TSNS will harbor either a missense or a frameshift heterozygous mutation of the PHOX2B gene. These data further highlight the link between congenital malformations and tumor predisposition when a master gene in development is mutated.

Sleep Disturbances in Children with Attention Deficit Hyperactivity Disorder

The objective of the study was to compare polysomnographic patterns in two groups of preadolescent children with attention deficit hyperactivity disorder (ADHD) (a sleep clinic referral sample and a community sample) with control children. A prospective and observational study in the sleep clinic and the community was undertaken. Forty-seven ADHD children referred to the sleep clinic (ADHDcl), 53 ADHD children from a community survey (ADHDcom), and 49 control children underwent overnight polysomnography. Significant differences between the groups were observed for rapid-eye-movement (REM) sleep latency and percentage, and periodic limb movement index with associated arousals (PLMa). REM sleep latency was shorter in controls than ADHDcl and ADHDcom (p < 0.01) and REM% was highest in controls and lowest in ADHDcl (p < 0.001). PLMa was higher in ADHDcl than the other groups (p < 0.001), but there were no differences in PLMa between ADHDcom and controls. ADHD children display significant alterations in their sleep patterns, and ADHDcl are more likely to have an elevated PLMa than ADHDcom. In addition, REM sleep is affected by ADHD. We postulate that ADHDcl may represent a subset of children with ADHD at high risk for hyperactivity during sleep.

Odds, prevalence and predictors of sleep problems in school-age normal children.

The objectives of the study were to describe the prevalence, odds, and predictors of 36 paediatric sleep behaviours and describe their coexistence in a school‐age normal population. The design was community‐based questionnaire survey of sleep–wake patterns, sleep environment, and 36 sleep behaviours indicative of six sleep disorder‐subscales using the Health‐Behaviour Questionnaire. A caregivers’ report of 3045 children aged 6–13 years in Belgium constituted the participants. Prevalence of each sleep behaviour was calculated. Log‐linear modelling within and between the sleep disorder‐subscales was used to screen for coexistence. The effect size of selected night‐time parameters to the likelihood of sleep behaviours and disorder‐subscale was expressed as odds ratios via logit regression analysis. Significant differences in sleep–wake patterns were found between weekday and weekend. Ranking by odds showed that: (1) sleep problems such as ‘tired when waking up’, ’repetitive limb movements’, ‘going to bed reluctantly’, and ‘sleep paralysis’ and; (2) the disorder‐subscale ‘excessive somnolence’ are common in children. Coexistences within and between disorder‐subscales of sleep problems are evident in a school‐age, normal population. These results suggest that disorders of excessive somnolence (DES) are highly prevalent in a non‐clinical sample of school‐age children. Furthermore, sleep‐onset latency and a noisy, not well‐darkened room are predictive towards the odds for exhibiting sleep problems and disorders. It is advocated that more information on the importance of good sleep–wake hygiene should reach parents and children.

Periodic limb movement disorder of sleep in children

To characterize periodic limb movement disorder (PLMD) in a cohort of prepubertal children we examined sleep‐related identifiable differences between children with PLMD and attention‐deficit/hyperactivity disorder (ADHD), PLMD alone, and age‐matched controls. Children were selected from a chart review of all children referred to a pediatric sleep medicine center and from a community survey of 5–7‐year‐old‐children. Polysomnography (PSG) and parental report data from all children identified as having periodic limb movement index (PLMI) >5 were reviewed and compared with a cohort of age‐matched controls. A total of 8.4% of children in the clinic‐referred sample, and 11.9% of the children recruited from the community had PLMI >5. Of those, 44.4% were identified as having ADHD. Children with PLMD had significantly lower percentage of rapid eye movement (REM) than control children (P < 0.001). Children in the PLMD/ADHD group had a significantly greater number of arousals associated with PLM (PLMa) than children with PLMD only (P < 0.05). While a relationship between ADHD and PLMD was observed, it was weaker than previous reports (Chervin, R. D. et al. Sleep, 2002; 25: 213; Chervin, R. D. and Archbold, K. H. Sleep, 2001; 24: 313; Picchietti et al. J. Child Neurol., 1999; 13: 588; Picchietti et al. Mov. Disord., 1999; 14: 1000; Picchietti and Walters Sleep, 1999; 22: 297). Children in the PLMD/ADHD group were more likely to have PLMas than were children with PLMD only. We postulate that rather than a direct relationship between ADHD and PLMD, this link may be mediated by the presence of reduced REM sleep and more importantly by the sleep fragmentation associated with PLM‐induced arousals.

Obesity Rather Than Severity of Sleep-Disordered Breathing as the Major Determinant of Insulin Resistance and Altered Lipidemia in Snoring Children

Objective. Sleep-disordered breathing (SDB) is associated with insulin resistance and dyslipidemia in adults and in obese children. However, the prevalence of such metabolic abnormalities among snoring children is unknown. This study was done to prospectively assess the relative contribution of SDB and obesity to metabolic disturbances in a large cohort of snoring children. Methods. Measurements of fasting serum glucose, insulin, and lipids were obtained after polysomnographic evaluation in 116 snoring children and in 19 control subjects. Insulin resistance was assessed using the insulin/glucose ratio (I/G ratio) and homeostasis model assessment (HOMA). Results. A total of 135 children (79 boys; mean age: 8.9 ± 3.5 years) were studied. Sixty-four children had moderate to severe SDB (AHI = 5 per hour of total sleep time [TST]), 52 had mild SDB (AHI = 1 but <5 per hour of TST), and 19 were control subjects (AHI <1 per hour of TST). Seventy of these children were obese. No significant correlations were found between AHI, lowest arterial oxygen saturation, or arousal index and serum insulin, serum glucose, I/G ratio, HOMA, or serum lipids for either the whole group or the obese children only. However, significant positive correlations were found between I/G ratio and relative BMI (relBMI; r = 0.58), HOMA and relBMI (r = 0.52), triglycerides and relBMI (r = 0.30), and high-density lipoprotein and relBMI (r = 0.50). No significant differences were found in relBMI, I/G ratio, and lipid levels between boys and girls. Conclusions. Among children with suspected SDB, insulin resistance and dyslipidemia seem to be determined primarily by the degree of body adiposity rather than by the severity of SDB.

Neurocognitive dysfunction and sleep in children: from human to rodent

Sleep disturbance in children, whether because of poor sleep hygiene or sleep-related breathing disorders, is associated with significant behavioral and neurocognitive deficits. The mechanisms by which sleep disturbance contributes to the daytime manifestations are unclear, although it seems that sleep fragmentation and intermittent hypoxia are important. The long-term outcome for children with untreated diseases leading to sleep disruption is currently unknown. Increased awareness and early identification and treatment of conditions that lead to altered sleep should yield improved neurocognitive outcomes in affected children.

The effect of stimulants on sleep characteristics in children with attention deficit/hyperactivity disorder

OBJECTIVE To investigate the effects of stimulant medications on subjective and objective sleep characteristics of children with attention deficit/hyperactivity disorder (ADHD) compared with control children. METHODS An observational study in the sleep clinic and the community. Children with characteristics of ADHD, both stimulant-medicated (n=53), and non-medicated (n=34), together with control children (n=53) completed a sleep habits questionnaire prior to undergoing full overnight polysomnographic assessment. RESULTS Medicated and non-medicated ADHD subjects were reported to have more sleep disturbances compared with controls. Both groups of ADHD children also demonstrated decreased REM sleep percentage compared with controls (P=0.006 for ADHDmed; P=0.02 for ADHDnon). However, the use of stimulant medication (n=53) was not associated with differences in subjective sleep quality or objective sleep measures, compared to ADHD children not taking any medication (n=34; P=n.s.). CONCLUSIONS Despite the high prevalence of reported sleep disturbance in children with ADHD, stimulant medication appears to have minimal effects on subjective and objective sleep characteristics in children with reported ADHD.

Coming to Autoethnography: A Mental Health Nurse’s Experience

In this article, the authors outline how a doctoral student came to use autoethnography within a narrative inquiry study exploring the experiences of being an adult child of a parent with a psychosis. Throughout the article, they discuss the researchers experiences and identify techniques they found useful in preparing for the present research process. As a qualitative research method, autoethnography is useful for making connections between researcher and participant, deepening interpretive analysis of both common and differing experiences, and producing knowledge drawn from compassionate understanding and rigorous reflection.

Developing resilient children and families when parents have mental illness: a family-focused approach.

There is substantial evidence supporting the need for effective intervention for children and families living with parental mental illness. However, translation of this knowledge into mental health workforce practice remains variable, with a range of clinical practices and models of care evident. Nurses, who constitute the majority of the mental health workforce, are in prime positions to support children and families and provide preventative measures, identify those at risk, and intervene early. In this paper, we provide a framework for practice for nurses working with consumer parents. We contend that traditional models of nursing practice concentrating on the consumer are insufficient in meeting the needs of children and families living with parental mental illness. A focus on families needs to be core business for mental health nurses. A family-focused approach can be used to prevent problems for children and their families, and identify their strengths as well as vulnerabilities. Family-focused care is a useful framework from which to support families and address the challenges that might arise from parental mental illness, and to build individual and family resilience.