Swallowing problems persist for children with SMA type 1 on DMTs
Study: Assessment crucial regardless of motor function level, treatment received
Written by |
- Dysphagia (swallowing problems) affects 62% of children with SMA type 1.
- Problems include difficulty controlling food, fatigue, and oral leakage.
- A comprehensive swallowing assessment is vital for all SMA type 1 children.
Problems with swallowing, also called dysphagia, remain a concern for many children with spinal muscular atrophy (SMA) type 1 despite available treatments, a real-world study reports.
Researchers examined swallowing in patients with SMA type 1 receiving disease-modifying therapies (DMTs). They found that about 62% met criteria for dysphagia on at least one rating system. Even for participants with otherwise good motor function, subtle problems with the safety or efficiency of swallowing often remained.
“Accordingly, swallowing assessment should be extended to all affected children, irrespective of motor function level or DMT received,” the team wrote.
The study, “Swallowing assessment in spinal muscular atrophy type 1: a real-world study of dysphagia in children receiving disease-modifying therapies,” was published in Neuromuscular Disorders.
Swallowing function in treated SMA type 1 children poorly characterized
In SMA, genetic mutations cause progressive muscle weakness and wasting. SMA type 1 is the most common and one of the most severe forms.
Dysphagia is an SMA symptom caused by weakness and fatigue in the muscles that control the face, mouth, and neck. It can increase the risk of choking or inhaling food into the airways and may negatively affect nutrition.
“Although disease-modifying therapies … have markedly improved motor outcomes, swallowing function in treated children with SMA type 1 remains poorly characterized,” the researchers wrote.
To address this research gap, the Italy-based team conducted swallowing assessments in 53 children with SMA type 1. The children started receiving a DMT — Spinraza (nusinersen), Zolgensma (onasemnogene abeparvovec), or Evrysdi (risdiplam) — at a median age of 4.4 months. Swallowing assessment occurred at a median age of 44.7 months (more than 3.5 years).
62.2% of children had swallowing impairments on at least 1 assessment
Among the used metrics, the Food Intake LEVEL Scale (FILS) and the Pediatric Functional Oral Intake Scale (p-FOIS) assess how much food the child is eating orally (as opposed to with a feeding tube) and the child’s functional ability to eat, respectively. For young children, the researchers also asked caregivers to complete the Oral and Swallowing Abilities Tool, a checklist of mouth movement and swallowing function.
In total, 62.2% of participants had swallowing impairments on at least one of these assessment tools.
“The observed prevalence of impairment is comparable to rates reported in other treated SMA type 1 cohorts, supporting the persistence of clinically relevant swallowing dysfunction despite DMTs,” the researchers wrote.
Another tool, the Mealtime Assessment Scale (MAS), evaluates the safety and efficiency of swallowing during a meal. At least one overt sign of dysphagia arose for 71.1% of the children. The most common problems were food or liquid remaining in the mouth after swallowing, coughing to expel inhaled food or liquid, and difficulty controlling the movement of food or liquid in the mouth.
The efficacy portion of MAS assesses how well children perform eating and swallowing behaviors. On this part, 77.4% had at least one problem. Excessive time spent chewing or manipulating food in the mouth, fatigue, and food leakage from the mouth while chewing were among the most common concerns.
Some of the children with problems on MAS had normal scores on other assessments.
“The identification of subtle signs of unsafe or inefficient swallowing even in children with a full oral diet … supports systematic monitoring rather than symptom-driven referral alone,” the team noted.
These findings indicate that improvements in gross motor outcomes following DMT administration may be associated with improvements in swallowing performance, but the latter cannot be reliably inferred from motor outcomes alone.
Next, the researchers assessed the relationship between dysphagia and other SMA symptoms. They found that overall motor abilities correlated significantly with MAS, FILS, and p-FOIS scores. Children who could sit unassisted also had significantly better swallowing performance than children who couldn’t sit.
They also looked for differences in swallowing depending on which DMTs children received. Children who started on Spinraza and later transitioned to Evrysdi tended to have poorer swallowing and sitting ability than children on Evrysdi, Zolgensma, or Spinraza plus Zolgensma. Swallowing scores were also lower in the Spinraza-only group compared with other regimens.
“These findings indicate that improvements in gross motor outcomes following DMT administration may be associated with improvements in swallowing performance, but the latter cannot be reliably inferred from motor outcomes alone,” the researchers wrote.
Future studies will be needed to further clarify the causes and progression of dysphagia in SMA patients, “including whether early swallowing profiles predict later outcomes, particularly in children who feed without consistency restrictions,” the scientists wrote.
Overall, the study identified a clinical profile of safety and efficacy concerns among children with SMA type 1 dysphagia.
“Awareness of this profile may guide the development of tailored rehabilitation and feeding management strategies,” the team added.
