Following disease progression in motor neuron disorders with 3 motor unit number estimation methods

Muscle Nerve. 2019 Jan;59(1):82-87. doi: 10.1002/mus.26304. Epub 2018 Nov 29.

Abstract

Introduction: The objective of this study was to evaluate a recently developed motor unit number estimation (MUNE) method, MScanFit MUNE (MScan), as a measure of disease progression in amyotrophic lateral sclerosis (ALS) compared with compound muscle action potential (CMAP) amplitude and 2 traditional MUNE methods.

Methods: ALS patients were evaluated clinically using the ALS Functional Rating Scale-Revised (ALSFRS-R). MScan, multiple-point stimulation MUNE (MPS), and motor unit number index (MUNIX) were performed in the abductor pollicis brevis (APB) muscle at baseline (27 patients), 4 months (23 patients), and 8 months (16 patients).

Results: Of the 5 measures, MScan registered the largest decline (8.7% per month), compared with MPS (3.4%), MUNIX (4.8%), CMAP amplitude (2.0%), and ALSFRS-R (1.9%). Only MScan and ALSFRS-R registered significant decrements over 4 and 8 months.

Discussion: MScan may be useful as a sensitive, objective tool for quantifying motor unit loss in ALS. Muscle Nerve 59:82-87, 2019.

Keywords: ALS Functional Rating Scale; MScan, motor unit loss; MUNE, motor unit number estimation; MUNIX, multiple-point stimulation; amyotrophic lateral sclerosis; follow-up study.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Disease Progression
  • Electromyography
  • Evoked Potentials, Motor / physiology*
  • Female
  • Humans
  • Male
  • Middle Aged
  • Motor Neuron Disease / physiopathology*
  • Motor Neurons / physiology*
  • Muscle, Skeletal / physiopathology*
  • Retrospective Studies