Identifying fasciculation potentials in motor neuron disease: A matter of probability

Muscle Nerve. 2016 Feb;53(2):227-33. doi: 10.1002/mus.24712. Epub 2015 Oct 10.


Introduction: Fasciculations, the spontaneous activity of single motor units (MUs) are characteristic, but nonspecific for motor neuron disease (MND). We aimed to identify MU discharge properties to optimally differentiate MND patients from healthy controls.

Methods: High-density surface electromyography recordings were performed in the thenar muscles during 10 min of rest. MU discharges were classified as "isolated" when the interspike intervals (ISIs) before and after were > 250 ms, "continual" when both ISIs were ≤ 250 ms, or as "other".

Results: In patients (n = 30) compared with controls (n = 14), more MUs were active (9 vs. 3, P < 0.001) and generated relatively more isolated discharges (35% vs. 10%, P = 0.01). Two or more MUs with isolated discharges occurred more frequently in patients compared with controls (24% vs. <1% of 10-s windows, P < 0.001).

Conclusions: More frequent occurrence of multiple MUs showing isolated discharges may improve identification of patients with MND.

Keywords: amyotrophic lateral sclerosis; electromyography; fasciculations; firing pattern; motor unit discharges.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Action Potentials / physiology*
  • Adult
  • Aged
  • Electromyography
  • Fasciculation / diagnosis*
  • Fasciculation / etiology*
  • Female
  • Humans
  • Male
  • Middle Aged
  • Motor Neuron Disease / complications*
  • Muscle, Skeletal / physiopathology*
  • Probability*