Nocturnal polygraphy in neuromuscular disorders: is it a useful diagnostic tool?

Patients with neuromuscular diseases (NMDs) have a high incidence of sleep-related breathing disorders. These include obstructive sleep apnea (OSA), which is characterized by recurrent episodes of upper airway obstruction during sleep, resulting in intermittent hypoxemia and sleep fragmentation. Obstructive sleep apnea may be more common in patients with NMDs than in the general population.

To assess the prevalence of OSA through home polygraphy at a public university hospital during respiratory evaluations of patients with NMDs, and its contribution to the indication of non-invasive ventilation. It did not aim to validate a model for early indication.

The present prospective study collected data over the period from May 2021 to June 2024, using medical records and tests such as spirometry to evaluate pulmonary respiratory function, home polygraphy, and sleep assessments using the Epworth Sleepiness Scale (ESS) and a symptom questionnaire.

A total of 74 patients were included, 64.7% (n = 48) of whom had OSA. The most prevalent NMDs were muscular dystrophy (n = 22; 29.7%), myasthenia gravis (n = 13; 17.6%), and amyotrophic lateral sclerosis (ALS) (n = 11; 14.9%). Apnea-hypopnea index (AHI) values were higher in the supine position (11.6 ± 12.6) compared to the AHI in the non-supine position (7.0 ± 14.1), which indicates, on average, a mild degree of OSA. The ESS revealed that 40.5% of patients had scores indicating excessive daytime sleepiness (EDS).

The findings reinforce the importance of early OSA diagnosis in patients with NMDs.