Sleep related breathing disorders in adults with Down syndrome.

Background: While the prevalence of obstructive sleep apnoea syndrome among children with Down syndrome is reported to vary from 30 to 50%, the nocturnal respiratory patterns of adults with Down syndrome is not well known.

Objectives: The aim of this study is to evaluate sleep-related breathing disorders in a sample of adults with Down syndrome.

Methods: We studied the nocturnal respiratory patterns of 6 adults with Down syndrome, aged 28-53 years. All participants were monitored for 8 hours using a 12 channel polysomnograph. Respiratory events (apnoeic and hypopnoeic) were classified as obstructive or central, in relation to the presence or the absence of paradoxical breathing.

Results: All participants had respiratory pauses during sleep. 5 of them had an apnoea/hypopnoea index > 10, justifying the diagnosis of sleep apnoea syndrome. About 85% of the respiratory events were apnoeic, the others being hypopnoeic. Among all the respiratory events 89.2% were obstructive, whereas only 10.8% were central. The central events were almost always organised in very low and regular sequences and respiration frequently showed a true periodic pattern, consisting of short periods of augmented breath followed by central events causing oxygen desaturation.

Conclusions: According to the literature and in conjunction with the current study's results it could be hypothesised that the nocturnal respiratory pattern of adults with Down syndrome depends on several pathogenetic factors such as age, severity of upper airway abnormalities, body mass index (BMI), other pathological conditions and age-related brainstem dysfunction.