Correlation between tongue ultrasound parameters and swallowing dysfunction in patients with amyotrophic lateral sclerosis

Abstract Background This study investigated the relationships between tongue ultrasound parameters, including tongue thickness, cross-sectional area (CSA), and fasciculations, and swallowing dysfunction in patients with amyotrophic lateral sclerosis (ALS). We also compared tongue morphology between ALS patients and healthy controls and compared fasciculation detection rates between ultrasound and clinical visual assessment. Methods This retrospective case-control study included 107 ALS patients diagnosed at a tertiary hospital in China between February and July 2025 and 107 age- and sex-matched healthy controls. Tongue ultrasound was performed in the ultrasound department. A 3.5 MHz convex probe was used to measure mid-tongue thickness and CSA, and a 7.5 MHz linear probe was used for 30-second dynamic observation of fasciculations, graded using a modified Misawa 0–3 scale. Swallowing function was assessed using ALSFRS-R swallowing and bulbar-related scores. Spearman rank correlation analysis was performed. Results ALS patients had significantly lower tongue thickness and CSA than controls (3.1 ± 0.6 vs. 3.7 ± 0.5 cm; 13.9 ± 4.3 vs. 17.2 ± 4.3 cm²; both p < 0.001). Tongue thickness correlated positively with ALSFRS-R total score (rs = 0.304, p < 0.05) and swallowing subscore (rs = 0.203, p < 0.05), with a stronger correlation in bulbar-onset patients (rs = 0.730, p < 0.05). CSA was not significantly correlated with swallowing score. Ultrasound detected tongue fasciculations more frequently than clinical visual assessment (40.1% vs. 33.6%). Conclusions Reduced tongue thickness was associated with swallowing impairment in ALS, especially in bulbar-onset patients. CSA reflected overall tongue muscle bulk but was not significantly associated with swallowing score in this cohort. Ultrasound may complement visual assessment for detecting tongue fasciculations. The standardized procedure was performed in an ultrasound department and requires prospective validation before bedside application.