The research, led by Vanessa Campes Dannenberg and Maria L. Castro-Codesal of the University of Alberta, together with colleagues at the Hospital for Sick Children in Toronto and the Alberta Children’s Hospital in Calgary, examined the medical records of 115 children and young people with neuromuscular disorders who were recommended for home non-invasive ventilation, or NIV, between 2010 and 2023. Most of the participants were male, with a median age of 11.8 years at the time of ventilation initiation. The most common diagnoses were Duchenne muscular dystrophy, accounting for 39 percent of the cohort, congenital muscular dystrophies at 19 percent, and spinal muscular atrophy at 14 percent. Nearly every child in the study carried at least one additional chronic condition, with a median of four comorbidities per patient, underscoring how medically complex this population is.

The central question was deceptively simple: when three different sets of polysomnography-based criteria are applied to the same overnight sleep study, do they identify the same children as needing breathing support? The team compared the 2023 guidelines from the American College of Chest Physicians, known as CHEST, against the traditional American Academy of Sleep Medicine, or AASM, definitions of moderate-to-severe obstructive sleep apnea and nocturnal hypoventilation, and against a new set of REM-related criteria proposed by the authors themselves. The CHEST criteria, drawn from a European Respiratory Society statement on pediatric long-term ventilation, flag children whose end-tidal or transcutaneous carbon dioxide exceeds 50 mmHg for at least 2 percent of total sleep time, or rises by 10 mmHg above their waking baseline, or whose oxygen saturation drops below 90 percent for at least 2 percent of sleep time or five continuous minutes.

Those thresholds matter because they are far more sensitive than the older AASM definitions, which require carbon dioxide to exceed 50 mmHg for a full 25 percent of total sleep time before labeling a child as hypoventilating. The results were striking. Only 9 percent of the children met the AASM-based hypoventilation criterion, while the CHEST guidelines identified 25 percent, and the REM-related criteria caught 12 percent. For nocturnal hypoxemia, for which the AASM framework offers no initiation criterion at all, the CHEST guidelines identified 22 percent of the cohort and the REM-related criteria 15 percent. In total, 71 percent of the children met at least one NIV initiation criterion across the three criteria sets, but a meaningful minority were visible only through the newer lenses.

Agreement between the criteria sets, measured with kappa statistics, told a nuanced story. Overall agreement between the CHEST and REM-related criteria was moderate, with a kappa of 0.71, and agreement on nocturnal hypoxemia between those two sets was similarly moderate at 0.69. The strongest agreement, a kappa of 0.86, emerged between the CHEST and AASM criteria on the apnea-hypopnea index, which is unsurprising given that both frameworks use similar thresholds of five or more respiratory events per hour. The divergence, in other words, was not about counting apneas and hypopneas. It was about the slow, silent buildup of carbon dioxide and the dips in oxygen that occur without any discrete respiratory event, particularly during the muscle atonia of REM sleep.

That physiology is the heart of the study’s argument. In children with neuromuscular weakness, breathing during REM sleep depends heavily on the diaphragm, because the intercostal and upper airway muscles lose their tone in that stage. When the diaphragm is also weak, carbon dioxide accumulates and oxygen levels fall, often without producing a single scored apnea. As the disease progresses, these abnormalities spread into non-REM sleep and eventually into wakefulness, culminating in chronic respiratory failure. The authors’ proposed REM-related criteria were designed to capture this earliest phase, and the analysis showed that an additional 11 percent of children met REM-related indications that the AASM-based criteria missed entirely. Thirteen percent of the cohort, twelve children, met no AASM-based criteria at all but satisfied at least one CHEST and one REM-related criterion.

The study also looked at what happened after ventilation began. Ninety-six percent of the children, 111 in total, successfully started NIV, and 73 percent of them sustained the therapy for six to twelve months, the window the researchers chose to avoid the acclimatization period when adherence is typically unstable. Adherence was respectable: children used the machine for a median of six hours per night, and on a median of 60 percent of nights they managed more than four hours of use. Clinician-documented reports from routine visits described improvements in general health in 34 percent of children, better sleep quality in 36 percent, and improved breathing during sleep in 25 percent. Most children avoided emergency department visits, ward admissions, and intensive care during the follow-up period.

Notably, the study found no significant differences in lung function before and after NIV initiation in any of the criteria groups, and no differences in adherence or clinical outcomes between groups. The authors attribute this largely to the substantial overlap among the three groups, since most children met the apnea-hypopnea thresholds common to all criteria sets. They also caution that NIV does not reverse the decline in lung function driven by the underlying disease; at best, it slows the trajectory, and changes are influenced by disease-modifying therapies and the natural history of each disorder. Only about half of the cohort could perform lung function testing that met American Thoracic Society technical standards, further limiting those comparisons.

The findings carry real weight for clinical practice. Earlier work in children with Duchenne muscular dystrophy had already suggested that disease-specific criteria could prompt ventilation for an additional 22 percent of children compared with standard AASM definitions. This study extends that insight to a broader neuromuscular population and adds a physiological rationale: many children show REM-related hypoventilation or hypoxemia with a normal apnea-hypopnea index, and the CHEST guidelines, by lowering the carbon dioxide threshold and adding an explicit hypoxemia criterion, are built to detect exactly that pattern. This matters especially for conditions such as myotonic dystrophy, in which discrete respiratory events are less common but carbon dioxide retention can still be dangerous.

The researchers acknowledge the limits of their retrospective design, their reliance on chart documentation, and the overlap that prevented subgroup comparisons. They also note that future studies may be difficult to conduct, because withholding ventilation until advanced hypoventilation develops would now be ethically questionable. Still, their conclusion is clear and forward-looking: guidelines for children with neuromuscular disease should integrate disease-specific and sleep-stage-specific polysomnographic criteria, watching REM sleep closely for the first signs of failure. Caught early, supported by a mask and a machine at home, these children may avoid the steepest part of the respiratory decline that has long defined their prognosis.

Subject of Research: Polysomnographic criteria for initiating non-invasive ventilation in children with neuromuscular diseases

Article Title: Establishing polysomnographic criteria for initiation of non-invasive ventilation in children with neuromuscular diseases

Article References: Dannenberg, V. C., Amin, R., Anagnostopoulos, G., Adeleye, A., Bendiak, G. N., Kolski, H., & Castro-Codesal, M. L. (2026). Establishing polysomnographic criteria for initiation of non-invasive ventilation in children with neuromuscular diseases. Journal of Clinical Sleep Medicine, 22(1), Article 117. https://doi.org/10.1007/s44470-026-00102-x

Image Credits: AI Generated

DOI: 10.1007/s44470-026-00102-x

Keywords: neuromuscular disease, non-invasive ventilation, polysomnography, REM sleep, sleep-disordered breathing, nocturnal hypoventilation, Duchenne muscular dystrophy, spinal muscular atrophy, pediatric sleep medicine, CHEST guidelines, AASM criteria, nocturnal hypoxemia

The letter responds to a study by Dannenberg and colleagues, published earlier in the same journal, that set out to establish polysomnographic criteria for starting non-invasive ventilation in children with neuromuscular disease. That original investigation addressed a genuine gap. For decades, clinicians have relied on a patchwork of guidelines, expert consensus, and institutional habit when interpreting sleep studies in this population, and the thresholds used to declare a sleep study abnormal have varied widely between centers. Any serious attempt to standardize those thresholds therefore deserves attention, and the letter writers acknowledge the value of the effort even as they probe its foundations.

Polysomnography, the overnight sleep test at the center of this debate, records a remarkable array of physiological signals: brain electrical activity through electroencephalography, eye movements that mark rapid eye movement sleep, muscle tone at the chin and limbs, airflow at the nose and mouth, respiratory effort through chest and abdominal belts, and blood oxygen saturation through pulse oximetry, alongside carbon dioxide measurement where available. In healthy children, breathing during sleep is remarkably stable, particularly in non-REM stages. In children with weakened respiratory muscles, however, the physiology changes in characteristic ways, and understanding those changes is essential to understanding why the criteria debate matters so much.

The key vulnerability lies in REM sleep. During REM, the body’s skeletal muscles, with the exception of the diaphragm and the extraocular muscles, lose their tone as part of the brainstem’s protective mechanism that prevents sleepers from acting out dreams. In a child whose intercostal muscles and accessory breathing muscles are already weakened by conditions such as Duchenne muscular dystrophy or spinal muscular atrophy, this REM-related muscle atonia can leave the diaphragm working alone against the resistance of a floppy chest wall. The result is shallow, inefficient breathing confined to REM periods, with oxygen saturation drifting downward and carbon dioxide accumulating, often without any dramatic apneas to catch an automated scoring algorithm’s attention. This pattern, sometimes called REM-related hypoventilation, is typically the earliest sleep-breathing abnormality in progressive neuromuscular disease.

Because the earliest abnormalities are subtle and stage-specific, the choice of polysomnographic thresholds carries enormous weight. Should the trigger for considering ventilation be a certain number of oxygen desaturations per hour, a defined percentage of sleep time spent below a saturation cutoff, an elevated transcutaneous or end-tidal carbon dioxide level, or some combination of these? Each option has methodological trade-offs. Desaturation indices borrowed from adult obstructive sleep apnea practice may miss the slow, sustained gas exchange deterioration typical of neuromuscular disease, where the abnormality is hypoventilation rather than discrete apneic events. Carbon dioxide measures, though more directly relevant to hypoventilation, are technically finicky in children, prone to signal drift and displacement, and not uniformly available across sleep laboratories.

These technical uncertainties form one strand of the letter’s argument. The authors raise methodological considerations about how criteria derived from a particular patient population and a particular set of recording practices can be generalized. Reference values for pediatric sleep studies differ by age, and children with neuromuscular disease span a wide developmental range, from toddlers with congenital myopathies to adolescents with advanced dystrophinopathies. A single threshold applied across that spectrum risks misclassifying both the youngest patients, whose normal physiology differs from school-age children, and those with slowly versus rapidly progressive conditions, whose trajectories of respiratory decline follow very different clocks.

The clinical considerations the authors emphasize are equally important. Polysomnography captures a single night, a snapshot that may not represent a child’s typical sleep, particularly in an unfamiliar laboratory environment where the first-night effect can suppress REM sleep and mask the very abnormalities clinicians are hunting for. A child whose REM time is curtailed on the study night may appear deceptively normal. Conversely, transient illness, nasal congestion, or anxiety can exaggerate abnormalities. Serial monitoring, careful correlation with daytime symptoms such as morning headaches, excessive sleepiness, poor school performance, and frequent nocturnal awakenings, and attention to trends over time may matter as much as any single numeric cutoff.

The stakes of getting these criteria right extend well beyond the sleep laboratory. Long-term non-invasive ventilation reshapes family life. Research on children with neuromuscular diseases who use ventilators, including work by Johannsen and colleagues cited in the letter, has examined the impact of long-term ventilator use on health-related quality of life and the mental health of affected children and their families, highlighting the need for a revised perspective on how these burdens are weighed. Initiating ventilation is not merely a technical prescription; it commits families to nightly routines, equipment maintenance, and an enduring reminder of disease progression. Criteria that are too permissive risk imposing these burdens without benefit, while criteria that are too restrictive risk depriving children of an intervention that, when appropriately timed, can improve sleep quality, daytime functioning, and potentially survival.

The letter also underscores a broader lesson about how evidence accumulates in pediatric sleep medicine. Large randomized trials are difficult to conduct in rare diseases, and much practice has been built on observational data and expert opinion. Studies that attempt to formalize criteria, such as the Dannenberg investigation, are valuable precisely because they make the reasoning explicit and testable. Letters such as that from Munir and colleagues serve as the peer community’s quality control, pressing authors on methodology, generalizability, and clinical applicability. This dialectic, proposal followed by critique followed by refinement, is how a field gradually converges on standards that clinicians can trust and families can understand.

For clinicians caring for children with neuromuscular disease, the practical message is one of calibrated vigilance. Sleep studies should be interpreted with awareness of REM physiology, age-appropriate norms, and the limitations of single-night testing, and the decision to start ventilation should integrate polysomnographic findings with symptoms, lung function trends, and family circumstances. For researchers, the exchange highlights the need for longitudinal studies that follow children from before ventilation is initiated, tracking which criteria best predict benefit, and for harmonization of carbon dioxide measurement and scoring practices across laboratories. The Islamabad authors’ contribution, though brief in the letter format, helps keep a consequential debate honest: the numbers on a sleep report are only as meaningful as the physiology, methodology, and human context behind them. As non-invasive ventilation becomes an ever more central therapy for children with weakened breathing muscles, refining the criteria that govern its initiation is not an academic exercise but a question with lifelong consequences for the children and families at its center.

Subject of Research: Polysomnographic criteria for initiating non-invasive ventilation in children with neuromuscular diseases

Article Title: Methodological and clinical considerations for polysomnographic criteria guiding non-invasive ventilation initiation in pediatric neuromuscular diseases

Article References: Munir, A. B., Imran, H., & Faraz, N. (2026). Methodological and clinical considerations for polysomnographic criteria guiding non-invasive ventilation initiation in pediatric neuromuscular diseases. Journal of Clinical Sleep Medicine, 22(1), Article 143. https://doi.org/10.1007/s44470-026-00166-9

Image Credits: AI Generated

DOI: 10.1007/s44470-026-00166-9

Keywords: polysomnography, non-invasive ventilation, pediatric neuromuscular disease, sleep-disordered breathing, REM-related hypoventilation, Duchenne muscular dystrophy, spinal muscular atrophy, nocturnal hypoventilation, carbon dioxide monitoring, sleep medicine, clinical criteria, ventilator initiation