Spinal Muscular Atrophy: Chewing and Swallowing Problems

Patients with Spinal Muscular Atrophy (SMA) types 2 and 3 frequently report weakness of the muscles of mastication and bulbar impairment leading to chewing and swallowing issues.1 Patients with SMA type 1 have such significant bulbar weakness that precludes safe feeding and therefore have early prophylactic interventions to bypass the oral route.2 Patients with SMA type 4 do not appear to experience weakness affecting their ability to eat.3

In a survey including patients with SMA, approximately one third of patients reported at least one feeding or swallowing issue.4 Follow-up surveys refined and elaborated on this estimate. In a survey of patients with SMA type 2, 30% of these patients reported difficulty in opening their mouths, 28% experienced chewing difficulties, and 25% had difficulty swallowing.5 A more recent survey spanning patients with SMA types 2 and 3 confirmed chewing difficulties in 20% of patients and found patients reported high incidences of choking (30%) and difficulty conveying food to the mouth (20%) as additional frequent complaints.2 Not surprisingly, patients report longer mealtimes because of their feeding and swallowing issues.2

The causes of these feeding and swallowing difficulties in patients with SMA are multifactorial. Weakness impairing the patient’s ability to get food to the mouth, or to maintain appropriate head posture during eating, impede the pre-oral phase of eating.5,6 Weakness in biting and rapid fatiguing of the masticatory muscles will slow chewing or make chewing less effective.5 Patients with SMA can have craniofacial abnormalities that impact the facial structure or the oral cavity anatomy and further degrade the ability to chew.7 Finally, SMA can progress to involve cranial nerve innervated muscles and bulbar muscles and thereby impact swallowing.5,8

Ultimately, the major concerns with feeding and chewing difficulties in patients with SMA are aspiration and malnutrition.9,10 A consortium of SMA experts therefore advises regular evaluations of feeding ability and adequacy of dietary intake in all patients with SMA.1 Interventions can range from postural changes to gastrostomy placement, depending on the unique needs of the patient; addressing feeding issues is best done from a multidisciplinary approach.1


1. Mercuri E, Finkel RS, Muntoni F, et al. Diagnosis and management of spinal muscular atrophy: Part 1: Recommendations for diagnosis, rehabilitation, orthopedic and nutritional care. Neuromuscul Disord. Feb 2018;28(2):103-115.

2. Chen YS, Shih HH, Chen TH, et al. Prevalence and risk factors for feeding and swallowing difficulties in spinal muscular atrophy types II and III. J Pediatr. Mar 2012;160(3):447-451.e441.

3. Piepers S, van den Berg LH, Brugman F, et al. A natural history study of late onset spinal muscular atrophy types 3b and 4. J Neurol. Sep 2008;255(9):1400-1404.

4. Willig TN, Paulus J, Lacau Saint Guily J, et al. Swallowing problems in neuromuscular disorders. Arch Phys Med Rehabil. Nov 1994;75(11):1175-1181.

5. Messina S, Pane M, De Rose P, et al. Feeding problems and malnutrition in spinal muscular atrophy type II. Neuromuscul Disord. May 2008;18(5):389-393.

6. van den Engel-Hoek L, de Swart BJ, Erasmus CE, et al. Is head balance a major determinant for swallowing problems in patients with spinal muscular atrophy type 2? J Child Neurol. Aug 2008;23(8):919-921.

7. Houston K, Buschang PH, Iannaccone ST, et al. Craniofacial morphology of spinal muscular atrophy. Pediatr Res. Aug 1994;36(2):265-269.

8. van den Engel-Hoek L, Erasmus CE, van Bruggen HW, et al. Dysphagia in spinal muscular atrophy type II: more than a bulbar problem? Neurology. Nov 24 2009;73(21):1787-1791.

9. van Bruggen HW, van den Engel-Hoek L, van der Pol WL, et al. Impaired mandibular function in spinal muscular atrophy type II: need for early recognition. J Child Neurol. Nov 2011;26(11):1392-1396.

10. Finkel RS, Mercuri E, Meyer OH, et al. Diagnosis and management of spinal muscular atrophy: Part 2: Pulmonary and acute care; medications, supplements and immunizations; other organ systems; and ethics. Neuromuscul Disord. Mar 2018;28(3):197-207.