Assessment of the upper motor neuron in amyotrophic lateral sclerosis

Clin Neurophysiol. 2016 Jul;127(7):2643-60. doi: 10.1016/j.clinph.2016.04.025. Epub 2016 May 5.

Abstract

Clinical signs of upper motor neuron (UMN) involvement are an important component in supporting the diagnosis of amyotrophic lateral sclerosis (ALS), but are often not easily appreciated in a limb that is concurrently affected by muscle wasting and lower motor neuron degeneration, particularly in the early symptomatic stages of ALS. Whilst recent criteria have been proposed to facilitate improved detection of lower motor neuron impairment through electrophysiological features that have improved diagnostic sensitivity, assessment of upper motor neuron involvement remains essentially clinical. As a result, there is often a significant diagnostic delay that in turn may impact institution of disease-modifying therapy and access to other optimal patient management. Biomarkers of pathological UMN involvement are also required to ensure patients with suspected ALS have timely access to appropriate therapeutic trials. The present review provides an analysis of current and recently developed assessment techniques, including novel imaging and electrophysiological approaches used to study corticomotoneuronal pathology in ALS.

Keywords: Amyotrophic lateral sclerosis; Imaging; Motor neuron disease; Transcranial magnetic stimulation; Upper motor neuron.

Publication types

  • Review
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amyotrophic Lateral Sclerosis / diagnosis
  • Amyotrophic Lateral Sclerosis / diagnostic imaging
  • Amyotrophic Lateral Sclerosis / physiopathology*
  • Diffusion Tensor Imaging
  • H-Reflex
  • Humans
  • Magnetic Resonance Imaging
  • Motor Neurons / physiology*
  • Positron-Emission Tomography
  • Transcranial Magnetic Stimulation