The Prognostic Role of Obstructive Sleep Apnea at the Onset of Amyotrophic Lateral Sclerosis

Abstract

Background/objective: Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by the progressive loss of central and peripheral motor neurons. Some studies have found discordant data in the presence of sleep apnea in ALS patients. An obstructive component also occurs with upper airways hypotonia and muscle weakness that may result in an excessive reduction of airway lumen, leading to obstructive sleep apnea (OSA). The aim of this study was to assess the role of obstructive apneic events at disease onset in the ALS prognosis.

Methods: A longitudinal retrospective study was conducted on 42 clinically diagnosed ALS patients. The study population was divided into 2 groups according to their obstructive apnea/hypopnea index (AHIo): group 1 consisted of 20 patients with an AHIo ≥5 and group 2 consisted of 22 patients with an AHIo <5. Both groups were compared with regard to demographic, polygraphic, and respiratory function parameters as well as ALS characteristics (bulbar onset, time between onset and first check-up, time between diagnosis and first check-up, time between first check-up and death or tracheostomy).

Results: The mean survival in ALS patients with an AHIo ≥5 was significantly shorter than in ALS without OSA (p = 0.0237). The sniff nasal inspiratory pressure test was significantly correlated with AHIo, time of oxyhemoglobin saturation below 90% and the oxyhemoglobin desaturation index (p < 0.0001).

Conclusions: Our study highlights the importance of an early diagnosis of OSA in ALS patients, allowing the identification of ALS patients with an OSA phenotype (AHIo ≥5), who are characterized by a worse prognosis.