ENOrphanet Journal of Rare Diseases | Systematic Review of Swallowing and Feeding Assessments Following Disease-Modifying Treatments for Spinal Muscular Atrophy
Date: April 05, 2025
Classification: Frontiers
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This systematic review examines the methods and outcomes of swallowing and feeding function assessments in patients with spinal muscular atrophy (SMA) after receiving disease-modifying treatments (DMTs). It highlights the impact of different treatment timings and assessment approaches on swallowing function and emphasizes the importance of standardized evaluation tools.
Literature Overview
This article, titled 'Systematic Review of Swallowing and Feeding Assessments Following Disease-Modifying Treatment for Spinal Muscular Atrophy', published in the Orphanet Journal of Rare Diseases, reviews and summarizes the research on swallowing and feeding function in SMA patients after undergoing DMTs. The study analyzed 71 studies covering various swallowing assessment methods and their outcomes, emphasizing the importance of assessing swallowing function across different disease stages, particularly before and after treatment. It also points out that, although disease-modifying therapies have significantly improved overall motor function and survival rates, swallowing and feeding assessments remain highly heterogeneous, lacking standardized tools, which makes cross-study comparisons difficult.Background Knowledge
Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disorder caused by mutations in the SMN1 gene, leading to reduced SMN protein levels and affecting motor neuron function. Based on onset age and severity, SMA is classified into multiple types, with Type 1 being the most severe, often accompanied by swallowing and respiratory dysfunction, while Types 2 and 3 present milder symptoms. Swallowing difficulties are prevalent among SMA patients, especially those with Type 1, and often lead to complications such as malnutrition, aspiration, and pneumonia. In recent years, several disease-modifying treatments (DMTs), including nusinersen, onasemnogene abeparvovec, and risdiplam, have been approved. These therapies increase SMN protein levels through various mechanisms, improving patient prognosis. While these treatments significantly extend survival and enhance motor function, there remains a lack of systematic evaluation regarding their impact on swallowing function. This review aims to fill this gap by evaluating current swallowing assessment methods in the literature and exploring the effects of DMTs on swallowing and feeding function, highlighting the necessity of standardized assessment tools.
Research Methods and Experimental Design
The study employed a systematic literature review (SLR) approach, following the PRISMA guidelines, and searched Embase, MEDLINE, and Cochrane Central databases from inception through February 2024. The included studies involved SMA patients (Types 1–3) who had received treatment with nusinersen, onasemnogene abeparvovec, or risdiplam. Cross-sectional studies and case reports were excluded. Data extraction included patient age, SMN2 copy number, treatment type, swallowing assessment methods, and feeding status. Assessment methods were categorized into (1) clinical swallow evaluation and instrumental swallow evaluation, and (2) functional swallow outcomes, such as oral intake status and patient-reported outcomes (PROs). Study bias and quality were assessed using NICE, AHRQ, and Newcastle-Ottawa scales.Key Findings and Perspectives
Implications and Future Directions
The study highlights the heterogeneity in current swallowing function assessments and emphasizes the importance of introducing standardized tools in clinical trials. Future research should integrate multiple assessment methods, including imaging and patient-reported outcomes, to gain a comprehensive understanding of the effects of DMTs on swallowing and feeding functions. Additionally, the study recommends regular swallowing assessments before and after treatment to monitor disease progression and treatment response, aiding clinical decision-making. Long-term follow-up of swallowing function changes in Types 2 and 3 SMA patients remains an area for further investigation.
Conclusion
This review systematically examined the assessment methods and outcomes of swallowing and feeding function in spinal muscular atrophy (SMA) patients after disease-modifying treatments (DMTs). It was found that while DMTs significantly improved overall motor function and survival, swallowing assessments still lack a unified standard, affecting the comparability across studies. Patients treated in the asymptomatic stage showed better recovery in swallowing function, whereas those who developed symptoms after treatment exhibited significant individual variability. The study recommends the adoption of standardized swallowing assessment tools in clinical trials to more accurately evaluate treatment efficacy and emphasizes the importance of long-term monitoring of swallowing function. In the future, combining imaging and functional assessment methods will help better understand the improvement in swallowing function following DMTs, providing a stronger evidence base for clinical management.
