Prevalence and Clinical Implications of Sleep Disturbances Across SMA Phenotypes: A Systematic Review
Mario Hinojosa-Figueroa1, Sebastián Martínez-Lozada2, David Poma Jimenez1, Santiago Aynaguano Aynaguano,1, Lizeth Vinueza1, Jose E Leon-Rojas3
1NeurAll Research Group, 2University of South Alabama, 3Cerebro, Emoción y Conducta (CEC) Research Group, Universidad de las Américas (UDLA)
Objective:
Systematically evaluate the prevalence, characteristics, and clinical implications of sleep-disordered breathing (SDB) and polysomnographic abnormalities in patients with spinal muscular atrophy (SMA).
Background:
SMA is an autosomal recessive neuromuscular disorder with early and progressive respiratory involvement. Sleep disturbances, including obstructive and central apneas, nocturnal hypoventilation, and disrupted sleep architecture, contribute substantially to morbidity but remain underrecognized. Understanding these complications is critical for timely intervention and improved quality of life.
Design/Methods:
A systematic review was conducted following PRISMA 2020 guidelines and registered in PROSPERO. PubMed, Scopus, Web of Science, EMBASE, and VHL were searched through April 2025. Eligible studies included patients of any SMA type reporting polysomnographic or respiratory sleep outcomes. Risk of bias was assessed using NHLBI tools. Data were extracted on demographics, SDB, and sleep architecture.
Results:
Nineteen studies comprising 438 patients were included. SMA type 2 was most represented (55.5%), followed by type 1 (25.3%) and type 3 (14.8%). SDB prevalence was highest in SMA type 1 (64.4–100%), frequent in type 2 (26.67–100%), and variable in type 3 (14.29–100%). Obstructive patterns predominated (64.3%), followed by mixed (18.2%) and pseudo-obstructive (14.7%) patterns. Sleep architecture alterations occurred in 78.7% of patients, most commonly reduced total sleep time, low sleep efficiency, and abnormal REM distribution. Apnea-hypopnea index (AHI) varied across SMA types, with severe OSA in 43.8% of type 1 patients. Nocturnal hypoxemia and hypercapnia were frequent. Most studies had moderate methodological quality.
Conclusions:
SDB and sleep architecture disturbances are highly prevalent across SMA phenotypes, particularly in severe forms, and often precede daytime respiratory failure. Routine sleep evaluation and early ventilatory support are essential. Future studies should assess the impact of disease-modifying therapies on sleep outcomes.
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