The Motor Unit Number Index of Subclinical Abnormality in Amyotrophic Lateral Sclerosis.

Purpose: Diagnosis of amyotrophic lateral sclerosis (ALS) at an early stage is challenging, thus making the enrollment of these patients in clinical trials infeasible. In this study, we investigated the potential usability of motor unit number index (MUNIX) to detect denervation of clinically intact muscles of ALS patients.

Methods: Thirty-two first dorsal interosseous muscles of 26 ALS patients were evaluated with both MUNIX and needle electromyography.