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.

Background: Disease-modifying therapies (DMTs) have transformed the natural history of spinal muscular atrophy (SMA) type 1, revealing heterogeneous developmental trajectories and renewing interest in cognitive and language outcomes beyond gross motor function. Within an embodied cognition framework, sensorimotor experience, object manipulation, and interactions with the environment may shape early cognitive development. This study aimed to describe the cognitive, language, and motor development of treated children with SMA type 1 and to explore associations between gross motor abilities and neurodevelopmental outcomes. Methods: A retrospective observational study included 32 children aged 18–30 months with confirmed SMA type 1. Participants were assessed using the Children’s Hospital of Philadelphia Infant Test of Neuromuscular Disorders (CHOP-INTEND) at baseline (T0) and both CHOP-INTEND and the Bayley Scales of Infant and Toddler Development, Third Edition (BSID-III) at the time of neurodevelopmental assessment (T1). Associations among Fine Motor, Cognitive, Language, and Gross Motor scores were examined using Spearman’s correlations and multivariable rank-based regression. Results: Fine Motor scores showed inter-individual variability and were correlated with Cognitive (ρ = 0.647, p < 0.001) and Language (ρ = 0.753, p < 0.001) scores. The association between Fine Motor and Cognitive performance remained robust even after adjustment for gross motor function, assessed by CHOP-INTEND, indicating that fine motor ability is linked to cognitive outcome irrespective of overall motor severity. Conclusions: In our cohort, fine motor ability was associated with cognitive and language outcomes, regardless of gross motor severity. These findings suggest the important role of neurodevelopmental components, beyond gross motor function alone, supporting their systematic integration into the clinical characterization of children with treated SMA type 1.