Pattern difference of dissociated hand muscle atrophy in amyotrophic lateral sclerosis and variants

Muscle Nerve. 2015 Mar;51(3):333-7. doi: 10.1002/mus.24323. Epub 2015 Jan 29.

Abstract

Introduction: Split hand is considered to be a specific feature of amyotrophic lateral sclerosis (ALS).

Methods: We evaluated the pattern difference of intrinsic hand muscles of upper limb-onset ALS (UL-ALS), upper limb-onset progressive muscular atrophy (UL-PMA), brachial amyotrophic diplegia (BAD), and Hirayama disease (HD) by measuring objective electrophysiological markers.

Results: The abductor digiti minimi (ADM)/abductor pollicis brevis (APB) compound muscle action potential (CMAP) amplitude ratio was significantly higher in UL-ALS than other variants, but a considerable proportion of UL-ALS cases had an amplitude ratio in the range of other variants. Absent APB CMAP and abnormally high ADM/APB CMAP amplitude ratio (≥4) occurred only with UL-ALS. Conversely, an absent ADM CMAP was identified only in UL-PMA and BAD.

Conclusions: The absolute ADM/APB CMAP amplitude ratio was not specific for ALS; however, several findings from simple electrophysiological measurements may help predict prognosis in patients with motor neuron diseases and may be early diagnostic markers for ALS.

Keywords: amyotrophic lateral sclerosis; brachial amyotrophic diplegia, Hirayama disease; progressive muscular atrophy; split hand.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Action Potentials / physiology
  • Adolescent
  • Adult
  • Aged
  • Amyotrophic Lateral Sclerosis / diagnosis*
  • Amyotrophic Lateral Sclerosis / epidemiology*
  • Amyotrophic Lateral Sclerosis / physiopathology
  • Female
  • Hand / pathology*
  • Humans
  • Male
  • Middle Aged
  • Muscular Atrophy / diagnosis*
  • Muscular Atrophy / epidemiology*
  • Muscular Atrophy / physiopathology
  • Retrospective Studies
  • Young Adult