Cognition and behavior in pre-pubertal children with Prader-Willi syndrome and associations with sleep-related breathing disorders

Long-term effect of growth hormone on sleep-disordered breathing in Malaysian children with Prader-Willi syndrome: a retrospective study

STUDY OBJECTIVES

The effect of recombinant human growth hormone (rhGH) on sleep-disordered breathing (SDB) in Malaysian children with Prader-Willi syndrome (PWS) is under-investigated. We determined (1) the short- and long-term effects of rhGH and (2) factors associated with worsening SDB in children with PWS receiving rhGH.

METHODS

This retrospective study included children with PWS (with and without rhGH) who had undergone at least 1 polysomnography. Outcomes measured were the presence of SDB before and after starting rhGH and the progress of SDB with and without rhGH. Serial insulin-like growth factor 1 (IGF-1) measurements were recorded.

RESULTS

One-hundred and thirteen polysomnograms were analyzed. The majority (92.3%) of initial polysomnograms showed SDB, with a median (interquartile range) apnea-hypopnea index of 5.0 (2.6, 16.3) events/h. The age for receiving rhGH was a median (IQR) of 1.9 (0.7, 3.4) years. One-third (36.8%) had worsening SDB after initiating rhGH, which was associated with higher IGF-1 levels post-rhGH (P = .007). After a median of 5 years of rhGH, 73.6% maintained or reduced their positive airway pressure settings. Without rhGH, 80% had increased their positive airway pressure settings. Worsening SDB while on rhGH was associated with higher body mass index, lower rhGH dose, higher IGF-1 levels, and non-15q deletion.

CONCLUSIONS

The majority of Malaysian children with PWS had SDB. At initiation of rhGH, one-third of patients had worsening SDB, associated with increased IGF-1 levels. Stabilization of SDB was more frequently seen in those receiving long-term rhGH. Worsening SDB while on rhGH was associated with a higher body mass index, receiving a lower dose of rhGH, higher IGF-1 levels, and non-15q deletion.

CITATION

Tan YT, Azanan MS, Hng SY, et al. Long-term effect of growth hormone on sleep-disordered breathing in Malaysian children with Prader-Willi syndrome: a retrospective study. J Clin Sleep Med. 2024;20(8):1291-1299.

Long-Term Growth Hormone Treatment of Children with PWS: The Earlier the Start, the Better the Outcomes?

Long-term effects of growth hormone (GH) treatment in young children with Prader-Willi syndrome (PWS) have never been compared with untreated age-matched controls with PWS, and it is unclear if starting GH in the first year of life is safe and more effective than starting GH in early childhood. We investigated the effects of long-term GH on body composition, anthropometrics and cognition in young children with PWS compared to untreated controls and assessed whether starting GH in the first year of life is optimal and safe. An open-label, prospective study was performed, comparing GH-treated children with untreated controls, and comparing children who started GH in the first year of life (subgroup A) with children who started between 2–5 years (subgroup C). A total of 82 GH-treated children with PWS and 22 age-matched controls with PWS were included. The main outcome measures were body composition, anthropometrics, IQ, and safety parameters. After 8 years, GH-treated children had significantly better body composition and were taller than age-matched controls. Subgroup A had a lower FM% trajectory during treatment than subgroup C and showed a greater and longer-term increase in the LBM index. After 8 years, subgroup A had a lower trunk/peripheral fat ratio (p = 0.043) and higher IQ (p = 0.043). No adverse effects of starting GH in the first year were found. Children with PWS who received long-term GH had a better body composition and growth than untreated age-matched controls and starting GH in the first year of life was optimal and safe.

Daytime sleepiness and emotional and behavioral disturbances in Prader-Willi syndrome

Individuals with Prader-Willi syndrome (PWS) often have excessive daytime sleepiness and emotional/behavioral disturbances. The objective of this study was to examine whether daytime sleepiness was associated with these emotional/behavioral problems, independent of nighttime sleep-disordered breathing, or the duration of sleep. Caregivers of individuals with PWS (aged 3 to 25 years) completed the Pediatric Sleep Questionnaire (PSQ), Epworth Sleepiness Scale for Children and Adolescents (ESS-CHAD), and the parent version of the Developmental Behavior Checklist (DBC-P). Sleep adequacy was adjusted for age by computing sleep duration against age-specific recommendations. The associations between ESS-CHAD and the total DBC and its subscale scores were evaluated by linear regression, adjusted for sleep-related breathing difficulties, sleep adequacy, and body mass index (BMI). There were 54 responses for individuals with PWS (including 22 males) aged 4.4-24.0 (mean 12.5) years. Daytime sleepiness predicted a substantial proportion of the variance in total DBC-P scores in the unadjusted model (28%; β = 0.028; p < 0.001) and when adjusted for sleep adequacy, BMI, and sleep-related breathing difficulties (29%; β = 0.023; p = 0.007). This relationship was not moderated by BMI Z-scores, but the relationship was more prominent for children younger than 12 years than for children older than 12 years.Conclusions: These findings provide preliminary novel evidence that daytime sleepiness may drive the expression of emotional/behavioral disturbances, and should be explored as a potential modifiable risk factor for these disturbances in PWS, particularly pre-adolescent children.

Sleep disordered breathing in patients with Prader willi syndrome: Impact of underlying genetic mechanism

INTRODUCTION

Sleep-disordered breathing (SDB) is common in children with PWS. In the current study, we aimed to evaluate the severity of SDB in patients with PWS using polysomnography (PSG), and assess the effect of the underlying genetic mechanism on PSG parameters.

METHODS

Children with PWS, referred to our sleep laboratory between March 2016 and January 2020 were enrolled. PSG parameters, demographic data, body mass index (BMI), and symptoms related to SDB were recorded. The effect of non-invasive ventilation strategies and the outcome of therapy on PSG parameters were evaluated.

RESULTS

In our study, 64.5% of the patients had severe sleep apnea syndrome (total apnea hypopnea index (AHI) ≥10 events/hour). 22.6% had significantly high (>5 events/hour) central sleep apnea. Patients with a deletion had significantly lower initial and mean SaO₂, longer sleep time SaO₂ under 90%, oxygen desaturation % and total AHI when compared to those with uniparental disomy. PSG parameters were similar between patients who did or didn't receive growth hormone treatment.

CONCLUSION

The majority of the PWS patients had severe sleep apnea syndrome characterized mainly by hypopneas which were accompanied by central apneas. There was a more severe impact on oxygen parameters and total AHI in patients with deletions.

Comparison of Frequency and Severity of Sleep-Related Breathing Disorders in Children with Simple Obesity and Paediatric Patients with Prader-Willi Syndrome

Sleep-related breathing disorders (SRBDs) can be present in children with simple obesity and with Prader–Willi syndrome (PWS) and influence an individual diagnostic and treatment approach. We compared frequency and severity of SRBDs in children with simple obesity and with PWS, both without and on recombinant human growth hormone (rhGH) treatment, and correlation of SRBDs with insulin resistance tests. A screening polysomnography-polygraphy (PSG), the oral glucose tolerance test (OGTT) and homeostasis model assessment of insulin resistance (HOMA-IR) were analysed in three groups of patients—with simple obesity (group 1, n = 30, mean age 14.2 years), patients with PWS without the rhGH therapy (group 2, n = 8, mean age 13.0 years) and during the rhGH treatment (group 3, n = 17, mean age 8.9 years). The oxygen desaturation index (ODI) was significantly higher in groups 2 and 3, compared to group 1 (p = 0.00), and hypopnea index (HI) was higher in group 1 (p = 0.03). Apnea–hypopnea index (AHI) and apnea index (AI) results positively correlated with the insulin resistance parameters in groups 1 and 3. The PSG values worsened along with the increasing insulin resistance in children with simple obesity and patients with PWS treated with rhGH that may lead to a change in the patients’ care.

Sleep Disorders in Childhood Neurogenetic Disorders

enetic advances in the past three decades have transformed our understanding and treatment of many human diseases including neurogenetic disorders. Most neurogenetic disorders can be classified as "rare disease," but collectively neurogenetic disorders are not rare and are commonly encountered in general pediatric practice. The authors decided to select eight relatively well-known neurogenetic disorders including Down syndrome, Angelman syndrome, Prader-Willi syndrome, Smith-Magenis syndrome, congenital central hypoventilation syndrome, achondroplasia, mucopolysaccharidoses, and Duchenne muscular dystrophy. Each disorder is presented in the following format: overview, clinical characteristics, developmental aspects, associated sleep disorders, management and research/future directions.

Promising effects of oxytocin on social and food-related behaviour in young children with Prader-Willi syndrome: a randomized, double-blind, controlled crossover trial

BACKGROUND

Prader-Willi syndrome (PWS) is known for hyperphagia with impaired satiety and a specific behavioural phenotype with stubbornness, temper tantrums, manipulative and controlling behaviour and obsessive-compulsive features. PWS is associated with hypothalamic and oxytocinergic dysfunction. In humans without PWS, intranasal oxytocin administration had positive effects on social and eating behaviour, and weight balance.

OBJECTIVE AND HYPOTHESES

To evaluate the effects of intranasal oxytocin compared to placebo administration on social behaviour and hyperphagia in children with PWS.

DESIGN

Randomized, double-blind, placebo-controlled, crossover study in a PWS Reference Center in the Netherlands.

METHOD

Crossover intervention with twice daily intranasal oxytocin (dose range 24-48 IU/day) and placebo administration, both during 4 weeks, in 25 children with PWS (aged 6 to 14 years).

RESULTS

In the total group, no significant effects of oxytocin on social behaviour or hyperphagia were found, but in the 17 children younger than 11 years, parents reported significantly less anger (P = 0·001), sadness (P = 0·005), conflicts (P = 0·010) and food-related behaviour (P = 0·011), and improvement of social behaviour (P = 0·018) during oxytocin treatment compared with placebo. In the eight children older than 11 years, the items happiness (P = 0·039), anger (P = 0·042) and sadness (P = 0·042) were negatively influenced by oxytocin treatment compared to placebo. There were no side effects or adverse events.

CONCLUSIONS

This randomized, double-blind, placebo-controlled study suggests that intranasal oxytocin administration has beneficial effects on social behaviour and food-related behaviour in children with PWS younger than 11 years of age, but not in those older than 11 years of age.

Acylated and unacylated ghrelin during OGTT in Prader-Willi syndrome: support for normal response to food intake

BACKGROUND

Prader-Willi syndrome (PWS) is characterized by hyperphagia with impaired satiety. PWS patients have very high acylated ghrelin (AG) with normal unacylated ghrelin (UAG) levels, resulting in an elevated AG/UAG ratio, suggesting an intrinsic defect in the ghrelin regulation. Normally, food intake induces satiety and a drop in AG and UAG levels, but it is unknown if these levels also decline in PWS.

OBJECTIVE

To evaluate whether the high AG levels in PWS decline in response to glucose intake during an oral glucose tolerance test (OGTT), and to investigate the effects of growth hormone (GH) treatment on this response.

METHOD

Serum levels of AG, UAG and AG/UAG ratio during an OGTT were determined in 24 GH-treated patients with PWS (median age 19·0, range 14·2-25·9 years) and in 10 GH-stop patients (of whom five were in GH-treated group; 18·5, 14·5-20·3 years).

RESULTS

In GH-treated and GH-stop young adults with PWS, there was a sharp decline of AG levels and a decrease of UAG levels in the first 30 min after the glucose load, which resulted in a lower AG/UAG ratio. GH-treated patients had significantly lower AG levels than GH-stop patients at baseline and during the OGTT. All UAG levels and AG/UAG ratios were lower in the GH-treated patients, although not significantly.

CONCLUSIONS

In young adults with PWS, an oral glucose load significantly reduces AG and UAG levels, suggesting normal regulation of the ghrelin axis by food intake. GH treatment results in lower AG levels at baseline and during OGTT, suggesting a more favourable metabolic profile. Our findings might suggest that the impaired satiety is not the result of an abnormal response of the orexigenic ghrelin to food intake.

Elevated ratio of acylated to unacylated ghrelin in children and young adults with Prader-Willi syndrome

Prader-Willi syndrome (PWS) is characterized by a switch from failure to thrive to excessive weight gain and hyperphagia in early childhood. Hyperghrelinemia may be involved in the underlying mechanisms of the switch. The purpose of this study is to evaluate acylated ghrelin (AG) and unacylated ghrelin (UAG) levels in PWS and investigate their associations with hyperphagia. This is a cross-sectional clinical study conducted in three PWS expert centers in the Netherlands and France. Levels of AG and UAG and the AG/UAG ratio were determined in 138 patients with PWS (0.2-29.4 years) and compared with 50 age-matched obese subjects (4.3-16.9 years) and 39 healthy controls (0.8-28.6 years). AEBSF was used to inhibit deacylation of AG. As a group, PWS patients had higher AG but similar UAG levels as healthy controls (AG 129.1 vs 82.4 pg/ml, p = 0.016; UAG 135.3 vs 157.3 pg/ml, resp.), resulting in a significantly higher AG/UAG ratio (1.00 vs 0.61, p = 0.001, resp.). Obese subjects had significantly lower AG and UAG levels than PWS and controls (40.3 and 35.3 pg/ml, resp.), but also a high AG/UAG ratio (1.16). The reason for the higher AG/UAG ratio in PWS and obese was, however, completely different, as PWS had a high AG and obese a very low UAG. PWS patients without weight gain or hyperphagia had a similar AG/UAG ratio as age-matched controls, in contrast to those with weight gain and/or hyperphagia who had an elevated AG/UAG ratio. The switch to excessive weight gain in PWS seems to coincide with an increase in the AG/UAG ratio, even prior to the start of hyperphagia.

[Obstructive sleep apnea-hypopnea syndrome in children: beyond adenotonsillar hypertrophy]

The prevalence of obstructive sleep apnea-hypopnea syndrome in the general childhood population is 1-2% and the most common cause is adenotonsillar hypertrophy. However, beyond adenotonsillar hypertrophy, there are other highly prevalent causes of this syndrome in children. The causes are often multifactorial and include muscular hypotonia, dentofacial abnormalities, soft tissue hypertrophy of the airway, and neurological disorders). Collaboration between different specialties involved in the care of these children is essential, given the wide variability of conditions and how frequently different factors are involved in their genesis, as well as the different treatments to be applied. We carried out a wide literature review of other causes of obstructive sleep apnea-hypopnea syndrome in children, beyond adenotonsillar hypertrophy. We organised the prevalence of this syndrome in each pathology and the reasons that cause it, as well as their interactions and management, in a consistent manner.

Prader Willi syndrome and obstructive sleep apnea: co-occurrence in the pediatric population

BACKGROUND

A high prevalence of obstructive sleep apnea (OSA) occurs in children with Prader-Willi syndrome (PWS). Yet, due in part to the relatively small samples previously used, the prevalence of OSA has varied greatly across studies. It is also unclear if factors such as age, gender, body mass index (BMI), or type of genetic imprinting are associated with increased risk for OSA among children with PWS.

OBJECTIVES

To evaluate the (a) prevalence of OSA, as well as narcolepsy, in pediatric populations diagnosed with PWS; (b) effects of age, gender, body mass index, and genetic imprinting on OSA severity; and (c) efficacy of adenotonsillectomy (AT) for decreasing OSA severity in this population.

METHODS

All studies assessing OSA among children with PWS through August 2013 were identified using the PubMed/Medline, Psych Info, Cochrane library, and Google Scholar data bases.

RESULTS

Fourteen studies of children diagnosed with PWS and who were assessed for OSA using polysomnography (PSG) met inclusion criteria (n = 224 children). The prevalence of OSA across studies was 79.91% (n = 179/224). Among youths with OSA, 53.07% had mild OSA, 22.35% moderate OSA, and 24.58% severe OSA. Narcolepsy was found to occur in 35.71% of children with PWS. Adenotonsillectomy was associated with improvement in OSA for most children with PWS. However, residual OSA was present in the majority of cases post-surgery.

CONCLUSION

This study confirms the high prevalence of OSA and narcolepsy among children with PWS. Screening for OSA and narcolepsy among children with PWS is recommended. In addition, while adenotonsillectomy was effective in reducing OSA for some children, alternative treatments may need to be considered, given the only moderate response rate.

Beneficial effects of growth hormone treatment on cognition in children with Prader-Willi syndrome: a randomized controlled trial and longitudinal study

BACKGROUND

Knowledge about the effects of GH treatment on cognitive functioning in children with Prader-Willi syndrome (PWS) is limited.

METHODS

Fifty prepubertal children aged 3.5 to 14 yr were studied in a randomized controlled GH trial during 2 yr, followed by a longitudinal study during 4 yr of GH treatment. Cognitive functioning was measured biennially by short forms of the WPPSI-R or WISC-R, depending on age. Total IQ (TIQ) score was estimated based on two subtest scores.

RESULTS

During the randomized controlled trial, mean sd scores of all subtests and mean TIQ score remained similar compared to baseline in GH-treated children with PWS, whereas in untreated controls mean subtest sd scores and mean TIQ score decreased and became lower compared to baseline. This decline was significant for the Similarities (P = 0.04) and Vocabulary (P = 0.03) subtests. After 4 yr of GH treatment, mean sd scores on the Similarities and Block design subtests were significantly higher than at baseline (P = 0.01 and P = 0.03, respectively), and scores on Vocabulary and TIQ remained similar compared to baseline. At baseline, children with a maternal uniparental disomy had a significantly lower score on the Block design subtest (P = 0.01) but a larger increment on this subtest during 4 yr of GH treatment than children with a deletion. Lower baseline scores correlated significantly with higher increases in Similarities (P = 0.04) and Block design (P < 0.0001) sd scores.

CONCLUSIONS

Our study shows that GH treatment prevents deterioration of certain cognitive skills in children with PWS on the short term and significantly improves abstract reasoning and visuospatial skills during 4 yr of GH treatment. Furthermore, children with a greater deficit had more benefit from GH treatment.

Executive summary of respiratory indications for polysomnography in children: an evidence-based review

OBJECTIVE

This comprehensive, evidence-based review provides a systematic analysis of the literature regarding the validity, reliability, and clinical utility of polysomnography for characterizing breathing during sleep in children. Findings serve as the foundation of practice parameters regarding respiratory indications for polysomnography in children.

METHODS

A task force of content experts performed a systematic review of the relevant literature and graded the evidence using a standardized grading system. Two hundred forty-three evidentiary papers were reviewed, summarized, and graded. The analysis addressed the operating characteristics of polysomnography as a diagnostic procedure in children and identified strengths and limitations of polysomnography for evaluation of respiratory function during sleep.

RESULTS

The analysis documents strong face validity and content validity, moderately strong convergent validity when comparing respiratory findings with a variety of relevant independent measures, moderate-to-strong test-retest validity, and limited data supporting discriminant validity for characterizing breathing during sleep in children. The analysis documents moderate-to-strong test-retest reliability and interscorer reliability based on limited data. The data indicate particularly strong clinical utility in children with suspected sleep related breathing disorders and obesity, evolving metabolic syndrome, neurological, neurodevelopmental, or genetic disorders, and children with craniofacial syndromes. Specific consideration was given to clinical utility of polysomnography prior to adenotonsillectomy (AT) for confirmation of obstructive sleep apnea syndrome. The most relevant findings include: (1) recognition that clinical history and examination are often poor predictors of respiratory polygraphic findings, (2) preoperative polysomnography is helpful in predicting risk for perioperative complications, and (3) preoperative polysomnography is often helpful in predicting persistence of obstructive sleep apnea syndrome in patients after AT. No prospective studies were identified that address whether clinical outcome following AT for treatment of obstructive sleep apnea is improved in association with routine performance of polysomnography before surgery in otherwise healthy children. A small group of papers confirm the clinical utility of polysomnography for initiation and titration of positive airway pressure support.

CONCLUSIONS

Pediatric polysomnography shows validity, reliability, and clinical utility that is commensurate with most other routinely employed diagnostic clinical tools or procedures. Findings indicate that the "gold standard" for diagnosis of sleep related breathing disorders in children is not polysomnography alone, but rather the skillful integration of clinical and polygraphic findings by a knowledgeable sleep specialist. Future developments will provide more sophisticated methods for data collection and analysis, but integration of polysomnographic findings with the clinical evaluation will represent the fundamental diagnostic challenge for the sleep specialist.

Practice parameters for the respiratory indications for polysomnography in children

BACKGROUND

There has been marked expansion in the literature and practice of pediatric sleep medicine; however, no recent evidence-based practice parameters have been reported. These practice parameters are the first of 2 papers that assess indications for polysomnography in children. This paper addresses indications for polysomnography in children with suspected sleep related breathing disorders. These recommendations were reviewed and approved by the Board of Directors of the American Academy of Sleep Medicine.

METHODS

A systematic review of the literature was performed, and the American Academy of Neurology grading system was used to assess the quality of evidence. RECOMMENDATIONS FOR PSG USE: 1. Polysomnography in children should be performed and interpreted in accordance with the recommendations of the AASM Manual for the Scoring of Sleep and Associated Events. (Standard) 2. Polysomnography is indicated when the clinical assessment suggests the diagnosis of obstructive sleep apnea syndrome (OSAS) in children. (Standard) 3. Children with mild OSAS preoperatively should have clinical evaluation following adenotonsillectomy to assess for residual symptoms. If there are residual symptoms of OSAS, polysomnography should be performed. (Standard) 4. Polysomnography is indicated following adenotonsillectomy to assess for residual OSAS in children with preoperative evidence for moderate to severe OSAS, obesity, craniofacial anomalies that obstruct the upper airway, and neurologic disorders (e.g., Down syndrome, Prader-Willi syndrome, and myelomeningocele). (Standard) 5. Polysomnography is indicated for positive airway pressure (PAP) titration in children with obstructive sleep apnea syndrome. (Standard) 6. Polysomnography is indicated when the clinical assessment suggests the diagnosis of congenital central alveolar hypoventilation syndrome or sleep related hypoventilation due to neuromuscular disorders or chest wall deformities. It is indicated in selected cases of primary sleep apnea of infancy. (Guideline) 7. Polysomnography is indicated when there is clinical evidence of a sleep related breathing disorder in infants who have experienced an apparent life-threatening event (ALTE). (Guideline) 8. Polysomnography is indicated in children being considered for adenotonsillectomy to treat obstructive sleep apnea syndrome. (Guideline) 9. Follow-up PSG in children on chronic PAP support is indicated to determine whether pressure requirements have changed as a result of the child's growth and development, if symptoms recur while on PAP, or if additional or alternate treatment is instituted. (Guideline) 10. Polysomnography is indicated after treatment of children for OSAS with rapid maxillary expansion to assess for the level of residual disease and to determine whether additional treatment is necessary. (Option) 11. Children with OSAS treated with an oral appliance should have clinical follow-up and polysomnography to assess response to treatment. (Option) 12. Polysomnography is indicated for noninvasive positive pressure ventilation (NIPPV) titration in children with other sleep related breathing disorders. (Option) 13. Children treated with mechanical ventilation may benefit from periodic evaluation with polysomnography to adjust ventilator settings. (Option) 14. Children treated with tracheostomy for sleep related breathing disorders benefit from polysomnography as part of the evaluation prior to decannulation. These children should be followed clinically after decannulation to assess for recurrence of symptoms of sleep related breathing disorders. (Option) 15. Polysomnography is indicated in the following respiratory disorders only if there is a clinical suspicion for an accompanying sleep related breathing disorder: chronic asthma, cystic fibrosis, pulmonary hypertension, bronchopulmonary dysplasia, or chest wall abnormality such as kyphoscoliosis. (Option) RECOMMENDATIONS AGAINST PSG USE: 16. Nap (abbreviated) polysomnography is not recommended for the evaluation of obstructive sleep apnea syndrome in children. (Option) 17. Children considered for treatment with supplemental oxygen do not routinely require polysomnography for management of oxygen therapy. (Option)

CONCLUSIONS

Current evidence in the field of pediatric sleep medicine indicates that PSG has clinical utility in the diagnosis and management of sleep related breathing disorders. The accurate diagnosis of SRBD in the pediatric population is best accomplished by integration of polysomnographic findings with clinical evaluation.