200 Section - Swallowing Trajectories in Spinal Muscular Atrophy Type II: The First Videofluoroscopic Swallowing Study Case Series Under Disease-Modifying Therapy

Spinal muscular atrophy (SMA) is a genetic neurodegenerative disease characterized by progressive motor weakness and atrophy. Dysphagia is an important but often under-recognized manifestation. While disease-modifying therapies have demonstrated benefits in motor function, their effect on swallowing function remains poorly understood.

Case Description: Three SMA type II patients (aged 13–28 years) with swallowing symptoms received disease-modifying therapy (one with Nusinersen and two with Risdiplam). Motor and swallowing functions were assessed at baseline, 1 year, and 2 years post-treatment. Motor outcomes were measured using the Hammersmith Functional Motor Scale–Expanded (HFMSE) and the Revised Upper Limb Module (RULM). Swallowing function was assessed by clinical scales (Functional Oral Intake Scale and Active Maximal Mouth Opening) and videofluoroscopic swallowing studies (VFSS). VFSS was analyzed using the Modified Barium Swallow Impairment Profile (MBSImP™), Oral Impairment Score (OIS), Pharyngeal Impairment Score (PIS), Penetration-Aspiration Scale (PAS), and the Dynamic Imaging Grade of Swallowing Toxicity (DIGEST).

Discussions: MBSImP™ analysis revealed that the most impaired oral components were bolus transport/lingual motion and oral transport. For the pharyngeal phase, all patients showed deficits in tongue base retraction and pharyngeal residue, while epiglottic movement, pharyngeal contraction, and pharyngoesophageal segment opening were impaired in two patients. PAS scores indicated consistent impairment with thin and nectar-thick liquids (frequently PAS ≥3–5), whereas honey-thick, pudding, and cookie consistencies were generally safe. Notably, motor and swallowing trajectories were not aligned: one patient improved in both domains, another improved in swallowing despite stable motor scores, and the third maintained motor stability but experienced swallowing decline.

Conclusions: This is the first study to use VFSS to track changes in swallowing function in patients with type II SMA following disease-modifying therapies. Persistent pharyngeal deficits and variable swallowing trajectories underscore the importance of VFSS follow-up for individualized dysphagia management and therapeutic monitoring in this population.