Elisabetta Verrillo

Sleep phenotypes of intellectual disability: a polysomnographic evaluation in subjects with Down syndrome and Fragile-X syndrome.

OBJECTIVE To analyze sleep architecture and NREM sleep alterations by means of the Cyclic Alternating Pattern (CAP) in children with Down syndrome (DS) and Fragile-X syndrome (fraX), the two most common causes of inherited mental retardation, in order to find out eventual alterations of their sleep microstructure related to their mental retardation phenotypes. METHODS Fourteen patients affected by fraX (mean age 13.1 years) and 9 affected by Down syndrome (mean age 13.8 years) and 26 age-matched normal controls were included. All subjects underwent overnight polysomnography in the sleep laboratory, after one adaptation night and their sleep architecture and CAP were visually scored. RESULTS FraX subjects showed a reduced time in bed compared to DS subjects, whereas DS subjects showed a lower sleep efficiency, a higher percentage of wakefulness after sleep onset, and a reduced percentage of stage 2 NREM compared to the other groups. Furthermore, DS and fraX subjects, compared to normal controls, showed a higher percentage of stage 1 NREM and a lower percentage of REM sleep. FraX subjects showed the most disrupted sleep microstructure with low total CAP rate and CAP rate in S2 NREM. Both patient groups showed a lower percentage of A1 and higher percentage of A2 and A3 compared to normal controls. CONCLUSIONS The analysis of CAP might be able to disclose new important findings in the sleep architecture of children with mental retardation and might characterize sleep microstructural patterns of the different phenotypes of intellectual disability. SIGNIFICANCE The NREM sleep microstructure alterations found in our subjects, associated with the reduction in REM sleep percentage, seem to be distinctive features of intellectual disability.

Sleep cyclic alternating pattern in normal school-age children

OBJECTIVES To evaluate cyclic alternating pattern (CAP) in sleep of school-age children in order to obtain a standardized database for CAP parameters in this age range. METHODS CAP parameters were quantified in 10 normal healthy subjects (6 males and 4 females, mean age 8.3 years; range 6-10 years). All subjects underwent polysomnography recordings for two consecutive nights in a standard laboratory setting. Sleep data were stored on computer using a 16-channel polysomnography digital system. Sleep macrostructure was visually scored according to the criteria by Rechtschaffen and Kales (Brain Information Service/Brain Research Institute, University of California, Los Angeles, 1968); CAP was visually scored following the criteria by Terzano et al. (Sleep Med 2 (2001) 537). RESULTS CAP rate showed a progressive increase with the deepness of sleep, with high values during slow wave sleep (SWS). CAP time showed its longest duration during non-REM (NREM) sleep stage 2 (S2), followed by SWS and sleep stage 1 (S1). No differences across NREM sleep stages were found for CAP cycle and phase B mean duration; on the contrary, phase A showed longer duration during SWS than in S1 and S2. Phases A1 were the most numerous (84.45%) followed by A3 (9.14%) and by A2 (6.44%). The distribution of phases A subtypes across NREM stages showed significant differences for the A1 subtypes that occurred more frequently during SWS than in S2 and S1 (and during S2 than in S1). Subtypes A3 were more frequent during S1 than SWS while no differences were found for subtype A2. The analysis of A1 interval distribution showed a log-normal-like distribution with a peak around 25 s for the A1 phases and no clear peak for A2-A3 phases. CONCLUSIONS The analysis of CAP in school-age children is characterized by an increase of CAP rate during SWS and a high percentage of A1 phases. The distribution of interval between consecutive A1 phases showed a peak around 25 s.

Obstructive Sleep Apnea Syndrome Affects Liver Histology and Inflammatory Cell Activation in Pediatric Nonalcoholic Fatty Liver Disease, Regardless of Obesity/Insulin Resistance

RATIONALE Obstructive sleep apnea syndrome (OSAS) and nonalcoholic fatty liver disease (NAFLD) are frequently encountered in obese children. Whether OSAS and intermittent hypoxia are associated with liver injury in pediatric NAFLD is unknown. OBJECTIVES To assess the relationship of OSAS with liver injury in pediatric NAFLD. METHODS Sixty-five consecutive children with biopsy-proven NAFLD (age, mean ± SD, 11.7 ± 2.1 yr; 58% boys; body mass index z score, 1.93 ± 0.61) underwent a clinical-biochemical assessment and a standard polysomnography. Insulin sensitivity, circulating proinflammatory cytokines, markers of hepatocyte apoptosis (cytokeratin-18 fragments), and hepatic fibrogenesis (hyaluronic acid) were measured. Liver inflammatory infiltrate was characterized by immunohistochemistry for CD45, CD3, and CD163, surface markers of leukocytes, T cells, and activated macrophage/Kupffer cells, respectively. OSAS was defined by an apnea/hypopnea index (AHI) greater than or equal to 1 event/h, and severe OSAS was defined by an AHI greater than or equal to 5 events/h. MEASUREMENTS AND MAIN RESULTS Fifty-five percent of children with NAFLD had nonalcoholic steatohepatitis (NASH), and 34% had significant (stage F ≥ 2) fibrosis. OSAS affected 60% of children with NAFLD; the presence and severity of OSAS were associated with the presence of NASH (odds ratio, 4.89; 95% confidence interval, 3.08-5.98; P = 0.0001), significant fibrosis (odds ratio, 5.91; 95% confidence interval, 3.23-7.42; P = 0.0001), and NAFLD activity score (β, 0.347; P = 0.029), independently of body mass index, abdominal adiposity, metabolic syndrome, and insulin resistance. This relationship held also in nonobese children with NAFLD. The duration of hemoglobin desaturation (Sa(O2) < 90%) correlated with increased intrahepatic leukocytes and activated macrophages/Kupffer cells and with circulating markers of hepatocyte apoptosis and fibrogenesis. CONCLUSIONS In pediatric NAFLD, OSAS is associated with biochemical, immunohistochemical, and histological features of NASH and fibrosis. The impact of hypoxemia correction on liver disease severity warrants evaluation in future trials.

Sleep breathing and periodic leg movement pattern in Angelman Syndrome: A polysomnographic study

OBJECTIVE The aim of this study was to evaluate the sleep breathing patterns and to detect the eventual presence of periodic leg movements (PLMs) in patients affected by Angelman syndrome (AS). METHODS Ten children with AS were recruited to participate in the study; the clinical diagnosis was confirmed by the genetic analysis (maternal 15q deletion, uniparental paternal disomy, or mutation of the UBE3A gene). All patients but two had presented epileptic seizures. Two age-matched groups of patients with mental retardation (MR) associated (MRE+) or not (MRE-) to epilepsy were used as control groups. All subjects underwent one polysomnographic recording, after one adaptation night. Sleep stages were scored according to standard criteria slightly modified in order to take into account the specific EEG patterns of AS, also the apnea/hypopnea index (AHI) was quantified; PLMs were identified and the PLM index (PLMI) was computed. The statistical analysis was carried out by means of the one-way ANOVA, followed by the Fisher LSD post-hoc test, when appropriate, and by means of the linear correlation coefficient between AHI and PLMI. RESULTS Sleep macrostructure showed only few significant differences between children with AS and the other two groups of subjects: AS patients showed higher percentage of wakefulness after sleep onset and sleep onset latency; moreover, the percentage of REM sleep was reduced in AS and in MRE+ subjects. A tendency for AS subjects to present a higher PLMI than the other two groups was also found. AHI >5 was found in 30% of AS subjects, in 30.8% of MRE+, and only in 20% of MRE- patients (chi(2) = 2.359, NS); 70% of AS patients, 38.5% of MRE+, and 46.7% of MRE- subjects had PLMI >5 (chi(2) = 3.088, NS). CONCLUSIONS These results confirm our previous questionnaire-based findings of a high prevalence of sleep breathing disorder and important PLMs in AS and allow us to hypothesize that epilepsy, rather than mental retardation, might exacerbate these sleep disorders. SIGNIFICANCE Sleep breathing disorder and PLMs might contribute to the cognitive impairment and to the worsening of life quality of subjects with AS and with MR (mostly those with epilepsy). Therefore, our findings suggest the need to explore these sleep disorders in children affected by MR and to set up a correct treatment.

Prader-Willi syndrome: Sorting out the relationships between obesity, hypersomnia, and sleep apnea

Purpose of review Although several studies in the last years have evaluated obesity, obstructive sleep apnea (OSAS), and excessive daytime sleepiness (EDS) in patients with Prader–Willi syndrome (PWS), their pathophysiologies and interactions and the role of treatment with growth hormone are not completely understood. The present review analyzes the contributing role of obesity, OSAS, and sleep structure abnormalities in determining the EDS and the role of specific treatment in improving the clinical outcome. Recent findings The studies on sleep structure of PWS patients show abnormalities of rapid eye movement (REM) sleep and a decrease in non-REM sleep instability, corroborating the hypothesis of the presence of a primary disorder of vigilance and the similarities with narcolepsy. These sleep alterations might also be linked to the action of mediators of inflammation (i.e. adiponectin or cytokines) determined by obesity. Obesity and hypothalamic dysfunction could be responsible for the primary abnormalities of ventilation during sleep that, in turn, might contribute to EDS. Although EDS seems to resemble narcolepsy, PWS patients do not present the other typical symptoms of narcolepsy. Summary The most consistent hypothesis for linking the three different symptoms of PWS is a primary central hypothalamic dysfunction. Further research is needed to evaluate the contribution of the upper airway resistance syndrome in the pathogenesis of EDS, the role of the alterations of sleep microstructure, the relationships between PWS and narcoleptic phenotype, the involvement of orexin/hypocretin, and the effects of drugs acting on REM sleep and/or wakefulness.

Analysis of NREM sleep in children with Prader-Willi syndrome and the effect of growth hormone treatment.

OBJECTIVES Only few studies are available in the literature on sleep in children with Prader-Willi syndrome (PWS) and one single study analyzed the cyclic alternating pattern (CAP) in young adults with PWS, showing that patients with a higher proportion of A1 subtypes presented less severe GH deficiency. The aims of our study were to evaluate CAP in children with PWS compared to an age-matched control group and to evaluate the differences between PWS children with (GH+) and without (GH-) GH therapy. METHODS Laboratory polysomnographic sleep recordings were obtained from 30 children with PWS (17 GH- and 13 GH+ patients) and 15 age-matched normal controls. RESULTS Compared to controls, PWS children had a reduction of sleep efficiency, of sleep stage 2 and of REM sleep. GH- PWS patients showed a global decrease in total CAP rate during S1 and S2 but not in SWS. In GH+ PWS patients, SWS CAP rate and A1 index were increased vs. GH- children. DISCUSSION The decrease in total CAP rate and all A subtypes might suggest the presence of a decreased NREM sleep instability in our PWS children and can be considered to be in agreement with the reported generalized hypoarousal state of PWS subjects. GH therapy is likely to increase CAP rate and A1 index during SWS in PWS patients.

Night‐to‐night consistency of at‐home nocturnal pulse oximetry testing for obstructive sleep apnea in children

At‐home nocturnal pulse oximetry has a high positive predictive value (PPV) for polysomnographically‐diagnosed obstructive sleep apnea (OSA) but no studies have been published testing the night‐to‐night consistency of at‐home nocturnal pulse oximetry for the evaluation of suspected OSA in children. We therefore determined the night‐to‐night consistency of nocturnal pulse oximetry as a diagnostic test for OSA in children.

Non-invasive positive pressure ventilation in children

Non-invasive positive pressure ventilation is increasingly used in children both in acute and in chronic setting. Clinical data supporting safety, efficacy and limitations in children are growing. Technical problems related to the ventilators performance and interfaces selection have not been fully resolved, especially for younger children. Non-invasive ventilation can be applied at home. Its use at home requires appropriate diagnostic procedures, accurate titration of the ventilators, cooperative and educated families and careful, well-organized follow-up programs.

Sleep architecture in infants with spinal muscular atrophy type 1.

OBJECTIVE Few reports on sleep patterns of patients with spinal muscular atrophy type 1 (SMA1) have been published and none on sleep microstructure. The aim of this study was to analyze sleep architecture and microstructure in a group of infants with SMA1, compared with age- and sex-matched controls. METHODS Twelve SMA1 patients (six males, mean age 5.9 months) and 10 controls (five males, mean age 4.8 months) underwent full polysomnography to evaluate their sleep architecture and microstructure by means of the cyclic alternating pattern (CAP). RESULTS Compared with control children, SMA1 patients showed increased sleep latency and apnea/hypopnea index. CAP analysis revealed a significant increase in the percentage of A1 CAP subtypes, a reduction of that of A3 subtypes and of A2 and A3 indexes (number/h), indicating a dysfunction of the arousal system in these patients. CONCLUSION The results indicate the presence of an abnormality of sleep microstructure in SMA1 patients, characterized by a reduction of A2 and A3 CAP subtypes. We hypothesize that SMA1 patients have reduced arousability during non-rapid eye movement sleep, which could be interpreted as additional evidence of central nervous system involvement in this disease.

Predicted and measured resting energy expenditure in children with spinal muscular atrophy 2.

We investigated in children with spinal muscular atrophy type 2 the consistency of 4 different equations for predicting resting energy expenditure (REE) compared with measured REE by using indirect calorimetry. In patients with spinal muscular atrophy type 2, measured REE was lower than predicted. We also found a correlation between energy consumption and motor skills.