300 Section - Masticatory Muscle Stiffness Correlates With Swallowing Function in Individuals With Spinal Muscular Atrophy: An ARFI/SWE Study

Wednesday, May 20, 2026

6:00 PM - 7:30 PM PT

Presenting Author/Autor expositor(s)

CL

Chiawei Lin, MD

Attending Physician
Department of Physical Medicine and Rehabilitation, National Taiwan University Hospital
Taipei, Taipei, Taiwan (Republic of China)

Co-Author/Coautor(s)

JS

Jeng-Yi Shieh, MD

Attending Physician
Department of Physical Medicine and Rehabilitation, National Taiwan University Hospital
Taipei, Taipei, Taiwan (Republic of China)
SW

Sz-Ting Wang, BS

SLP
Department of Physical Medicine and Rehabilitation, National Taiwan University Hospital
Taipei, Taipei, Taiwan (Republic of China)
YC

Ying-Chun Chen, MD

Attending Physician
Department of Physical Medicine and Rehabilitation, National Taiwan University Hospital Hsin-Chu Branch
Hsinchu City, Hsinchu, Taiwan (Republic of China)
PT

Po-Hsiang Tsui, PhD

Professor
Department of Biomedical Engineering, Chang Gung University, Taoyuan,Taiwan
Taoyuan, Taoyuan, Taiwan (Republic of China)
YC

Ya-Wen Chuang, BS

Student
Department of Biomedical Engineering, Chang Gung University, Taoyuan,Taiwan
Taoyuan, Taoyuan, Taiwan (Republic of China)
WC

Wen-Yu Chou, MD

Attending Physician
Department of Physical Medicine and Rehabilitation, National Taiwan University Hospital
Taipei, Taipei, Taiwan (Republic of China)

Corresponding Author/Autor a quien dirigir la corr(s)

WW

Wen-Chin Weng, MD,PhD

Attending Physician
Department of Pediatrics, National Taiwan University Hospital
Taipei, Taipei, Taiwan (Republic of China)

Objectives :

Masticatory dysfunction is increasingly recognized in spinal muscular atrophy (SMA), yet objective markers of craniofacial muscle involvement remain limited. SMA-related denervation and fibrosis may alter muscle stiffness measurable by acoustic radiation force impulse shear wave elastography (ARFI/SWE). This study compared masticatory muscle stiffness between SMA and controls and examined its associations with swallowing-related outcomes.

Design:

Fifty-seven SMA patients and 46 age-matched TDC were enrolled. ARFI/SWE quantified the shear-wave velocity (SWV, m/s) of the masseter and temporalis muscles. Swallowing-related assessments in SMA include EAT-10 questionnaire, muscle strength (lip, cheek, jaw, and laryngeal elevation), and tongue and cheek pressure and endurance using the Iowa Oral Performance Instrument. Student t test compared the muscle SWV between groups, and Pearson correlations examined associations between muscle SWV and swallowing-related measures within the SMA group.

Results:

Compared with controls, individuals with SMA demonstrated significantly higher SWV in the masseter (2.04 ± 0.52 vs. 1.84 ± 0.33 m/s, p = 0.021) and temporalis muscles (3.17 ± 1.00 vs. 2.36 ± 0.55 m/s, p < 0.001). Greater masseter stiffness was associated with absence of wet voice (r = 0.420, p = 0.026). Higher temporalis stiffness correlated with more severe swallowing symptoms (higher EAT-10 scores; r = 0.683), reduced lip, cheek, jaw, and laryngeal elevation strength, and greater tongue endurance (r = 0.429).

Conclusion:

Masticatory muscle stiffness is increased in SMA. The association between masticatory stiffness and swallowing performance suggests muscle-specific roles. Masseter stiffness may reflect compensatory oral sealing, whereas temporalis stiffness appears pathological and likely fibrosis-related, aligning with weaker swallow-related strength and higher EAT-10 scores. Its positive relationship with tongue endurance may indicate compensatory tongue engagement when masticatory muscles weaken. In conclusion, ARFI/SWE-derived masticatory muscle stiffness correlates with swallowing-related measures and may serve as a quantitative biomarker of bulbar involvement in SMA.