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

A M B van der Heul, R A J Nievelstein, Ruben van Eijk, F Asselman, C E Erasmus, I Cuppen, A J N Bittermann, E Gerrits, W L van der Pol, L van den Engel-Hoek

Research output: Contribution to journalArticleAcademicpeer-review


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).

Original languageEnglish
Pages (from-to)427-438
Number of pages12
JournalJournal of Neuromuscular Diseases
Issue number3
Publication statusPublished - 2023


  • SMN
  • Spinal muscular atrophy
  • Survival motor neuron gene
  • dysphagia
  • muscle ultrasound
  • oral motor function
  • videofluoroscopy


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