Swallowing Problems in Spinal Muscular Atrophy Types 2 and 3: A Clinical, Videofluoroscopic and Ultrasound Study

Article type: Research Article

Authors: van der Heul, A.M.B.^{a; *} | Nievelstein, R.A.J.^b | van Eijk, R.P.A.^{a; c} | Asselman, F.^a | Erasmus, C.E.^d | Cuppen, I.^a | Bittermann, A.J.N.^e | Gerrits, E.^f | van der Pol, W.L.^{a; 1} | van den Engel-Hoek, L.^{g; 1}

Affiliations: [a] Department of Neurology & Neurosurgery, UMC Utrecht, Brain Center, University Medical Center Utrecht, Utrecht, The Netherlands | [b] Department of Radiology & Nuclear Medicine, Imaging & Oncology Division, University Medical Center Utrecht, Utrecht, The Netherlands | [c] Biostatistics & Research Support, Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands | [d] Department of Pediatric Neurology, Donders Center for Neuroscience, Radboud University Medical Center, Amalia Children’s Hospital, Nijmegen, The Netherlands | [e] Department of Otorhinolaryngology-Head and Neck Surgery, University Medical Center Utrecht, Utrecht, The Netherlands | [f] Department of Languages, Literature and Communication, Utrecht Institute of Linguistics OTS, Utrecht University, Utrecht, The Netherlands | [g] Department of Rehabilitation, Donders Center for Neuroscience, Radboud University Medical Center, Nijmegen, The Netherlands

Correspondence: [*] Correspondence to: A.M.B. van der Heul, University Medical Center Utrecht, Wilhelmina Children’s Hospital, Kind& Communicatie, KJ 01.521.0, Postbus 85090, 3508 AB Utrecht, The Netherlands. E-mail: a.m.b.vanderheul@umcutrecht.nl.

Note: [1] W.L. van der Pol and L. van den Engel-Hoek have contributed equally.

Abstract: Background:Spinal muscular atrophy (SMA) is a hereditary motor neuron disorder, characterized by the degeneration of motor neurons and progressive muscle weakness. There is a large variability of disease severity, reflected by the classification of SMA types 1–4. Objective:The aim of this cross-sectional study was to determine the nature of swallowing problems and underlying mechanisms in patients with SMA types 2 and 3, and the relationship between swallowing and mastication problems. Methods:We enrolled patients (aged 13–67 years) with self-reported swallowing and/or mastication problems. We used a questionnaire, the functional oral intake scale, clinical tests (dysphagia limit, and timed test swallowing, the test of mastication and swallowing solids), a videofluoroscopic swallowing study (VFSS), and muscle ultrasound of the bulbar muscles (i.e. digastric, geniohyoid and tongue muscles). Results: Non-ambulant patients (n = 24) had a reduced dysphagia limit (median 13 ml (3–45), and a swallowing rate at the limit of normal (median 10 ml/sec (range 4–25 ml). VFSS revealed piecemeal deglutition and pharyngeal residue. We found pharyngo-oral regurgitation in fourteen patients (58%), i.e. they transported the residue from the hypopharynx back into the oral cavity and re-swallowed it. Six patients (25%) demonstrated impaired swallowing safety (i.e. penetration aspiration scale > 3). Muscle ultrasound revealed an abnormal muscle structure of the submental and tongue muscles. Ambulant patients (n = 3), had a normal dysphagia limit and swallowing rate, but VFSS showed pharyngeal residue, and muscle ultrasound demonstrated an abnormal echogenicity of the tongue. Swallowing problems were associated with mastication problems (p = 0.001).

Keywords: Spinal muscular atrophy, SMN, Survival motor neuron gene, oral motor function, dysphagia, videofluoroscopy, muscle ultrasound

DOI: 10.3233/JND-221640

Journal: Journal of Neuromuscular Diseases, vol. 10, no. 3, pp. 427-438, 2023