Assessing the Swallowing Function in Children with Spinal Muscular Atrophy: An Easily Accessible and Objective Multidimensional Approach.

Background: Spinal muscular atrophy (SMA), a genetic neuromuscular disease caused by lack of survival of motor neuron (SMN) protein, is characterized by muscular atrophy and respiratory and bulbar dysfunction. While swallowing disorders are common, they remain poorly studied.

Objectives: Our study aimed to explore 1) intraoral pressure measurements with the Iowa Oral Performance Instrument system and the reliability of a Swallowing Function Assessment Questionnaire (SFAQ) in healthy controls, and 2) evaluate their use as swallowing function biomarkers and the evolution of swallowing function over time in children with SMA.

Methods: We recruited 53 healthy children and 27 SMA patients all treated with SMN gene modulator therapy. Participants completed the SFAQ and underwent at least one measurement of maximal oral pressures (lingual, labial, and masseter).

Results: Mean oral normalized pressure index were lower (all sites p < 0.001) and mean SFAQ scores were higher (p < 0.001) in patients compared with healthy controls. Pressure evolution over 1 year in SMA patients for all three oral sites did not show significant differences. SFAQ scores correlated negatively with oral pressures at all three sites in patients.

Conclusions: Both tools provided new insights on the oral and pharyngeal phase of swallowing in SMA patients. In SMA patients, muscle strength in certain crucial anatomical regions during swallowing is weaker than in healthy children.