Exploring the Trajectory of Swallowing Within Psychomotor Development in Spinal Muscular Atrophy: Moving Toward Integrated Care

Abstract

Background: Spinal Muscular Atrophy type 1 (SMA type 1) is a genetic neuromuscular disease that typically presents before 6 months of age and is characterized by profound hypotonia, progressive muscle weakness, and early involvement of respiratory and bulbar musculature. Swallowing impairment (dysphagia) is a hallmark of SMA type 1 and significantly contributes to morbidity. Despite the documented benefits of disease-modifying therapies (DMTs) in terms of enhanced survival and motor outcomes, their impact on swallowing remains understudied. Aim: This study aims to longitudinally characterize swallowing function in children with SMA type 1 treated with DMTs, while contextualizing these findings in relation to the patients’ current motor abilities and cognitive performance. Materials and Methods: A single-center, longitudinal, observational study was conducted at IRCCS Besta, Milan, Italy, from 2021 to 2025. Swallowing function was evaluated using four validated scales (MAS, OrSAT, FILS, and p-FOIS), while motor and cognitive functions were assessed using CHOP-INTEND and age-appropriate cognitive tests (DQ/IQ). Patients were stratified by baseline swallowing status, pharmacological therapy, and age at DMT administration. Non-parametric statistical tests were applied. Results: No statistically significant changes in swallowing function were observed over one year in the overall cohort or its subgroups, despite significant improvements in motor function. MAS/e, FILS, and p-FOIS showed moderate associations with CHOP-INTEND and DQ/IQ scores. Conclusions: Swallowing function in children with SMA type 1 remained largely stable, while motor function significantly improved over one year, regardless of baseline swallowing status, DMT type, and age at administration. These findings underscore the need for standardized, longitudinal assessments of swallowing, motor, and cognitive functions in the management of SMA type 1.