Translation of surface electromyography into a clinically applicable objective bulbar assessment tool to improve measurement-based care in amyotrophic laterals sclerosis

Objective: This study aims to translate surface electromyography (sEMG) into a clinically applicable, objective tool for assessing bulbar involvement in amyotrophic lateral sclerosis (ALS). Methods: ; (2) associations with standardized functional outcomes and a biomechanical metric-stiffness-via mediation analysis; (3) discriminatory efficacy in distinguishing ALS+B and ALS-B from HC, as well as from each other, using machine learning classifications; and (4) robustness to common nonmotor confounders, including age, sex, and cognitive-linguistic impairments, through a comparison of discriminatory performance before and after adjustment for these factors. Results: ), (2) significant (or marginally significant) direct or stiffness-mediated indirect associations with the functional outcomes, and (3) consistently high discriminatory accuracy (0.82-0.85), both before and after adjustment for confounders. Conclusion: The sEMG framework demonstrates strong potential as a reliable, valid, and robust objective tool to detect subclinical neuromuscular changes throughout the prodromal and symptomatic phases of bulbar involvement in ALS, while remaining resistant against disease-related cognitive-linguistic impairments and disease-unrelated confounders. This tool may augment standard clinical evaluations, enabling earlier detection of bulbar involvement and measurement-based care in ALS.