Related Experiment Video
Updated: Jun 27, 2025
Author Spotlight: Studying Neuromuscular Responses and Motor Neuron Plasticity in Neurodegenerative Diseases
Published on: April 19, 2024
Could the motor unit number index be an early prognostic biomarker for amyotrophic lateral sclerosis?
Aude-Marie Grapperon1, Vincent Harlay1, Mohamed Boucekine2
1APHM, Timone University Hospital, Referral Center for Neuromuscular Diseases and ALS, ERN Euro-NMD Center, Marseille, France.
Objective:
To evaluate the associations between motor unit number index (MUNIX) and disease progression and prognosis in amyotrophic lateral sclerosis (ALS) in a large-scale longitudinal study.
Methods:
MUNIX was performed at the patient's first visit, at 3, 6, and 12 months in 4 muscles. MUNIX data from the patients were compared with those from 38 age-matched healthy controls. Clinical data included the revised ALS functional rating scale (ALSFRS-R), the forced vital capacity (FVC), and the survival of the patients.
Results:
Eighty-two patients were included at baseline, 62 were evaluated at three months, 48 at six months, and 33 at twelve months. MUNIX score was lower in ALS patients compared to controls. At baseline, MUNIX was correlated with ALSFRS-R and FVC. Motor unit size index (MUSIX) was correlated with patient survival. Longitudinal analyses showed that MUNIX decline was greater than ALSFRS-R decline at each evaluation. A baseline MUNIX score greater than 378 predicted survival over the 12-month period with a sensitivity of 82% and a specificity of 56%.
Conclusions:
This longitudinal study suggests that MUNIX could be an early quantitative marker of disease progression and prognosis in ALS.
Significance:
MUNIX might be considered as potential indicator for monitoring disease progression.
