RESUMEN
INTRODUCTION: We evaluated the association between muscle ultrasound, number of motor units, and clinical parameters, and assessed their utility for distinguishing amyotrophic lateral scleorisis (ALS) patients from healthy individuals. METHODS: Three muscle pairs (abductor pollicis brevis, abductor digiti minimi, and tibialis anterior) of 18 ALS patients and 18 controls underwent muscle ultrasound (echointensity and thickness) and assessment of motor unit number index (MUNIX). The clinical and functional status of participants were also assessed. RESULTS: Mean age of the patients was 53.8 ± 12.1 years, and score on the ALS Functional Rating Scale-Revised was 38.9 ± 4.1. Echointensity of all tested muscles of ALS participants was significantly higher than that of controls, but there was no significant difference in muscle thickness. Muscle echointensity correlated significantly with clinical and electrophysiological parameters. CONCLUSION: Echointensity of muscles was highly associated with clinical scales and MUNIX, confirming its relevance as an ancillary diagnostic test in ALS patients.