title: Origin of fasciculations in amyotrophic lateral sclerosis and benign fasciculation syndrome.
abstract: OBJECTIVE
  Fasciculation potentials (FPs) may arise proximally or distally within the peripheral nervous system. We recorded FPs in the tibialis anterior using 2 concentric needle electrodes, ensuring by slight voluntary contraction and electrical nerve stimulation that each electrode recorded motor unit potentials innervated by different axons.
  
  
  METHODS
  Time-locked FPs recorded from both electrodes, suggesting a spinal origin, were most frequent in benign fasciculation syndrome (44%) (P < .001) and amyotrophic lateral sclerosis without reinnervation (27%). Fewer time-locked FPs were found (14%) in the reinnervated tibialis anterior in amyotrophic lateral sclerosis (P < .001).
  
  
  CONCLUSIONS
  We conclude that in chronic partial denervation FPs are more likely to arise distally and that FPs in benign fasciculation syndrome more frequently arise proximally.
authors.affiliation: Translational Clinical Neurophysiology Unit, Instituto de Medicina Molecular and Institute of Physiology, Faculty of Medicine, University of Lisbon, Lisbon, Portugal2Department of Neurosciences, Hospital de Santa Maria, Lisbon, Portugal.
authors.forename: Mamede
authors.initials: M
authors.lastname: de Carvalho
authors.affiliation: Translational Clinical Neurophysiology Unit, Instituto de Medicina Molecular and Institute of Physiology, Faculty of Medicine, University of Lisbon, Lisbon, Portugal3Department of Neurology, Royal London Hospital, Queen Mary University of London, London.
authors.forename: Michael
authors.initials: M
authors.lastname: Swash
mesh_terms: D000328:Adult; D000368:Aged; D000690:Amyotrophic Lateral Sclerosis / Q000150:complications* / Q000473:pathology; D004558:Electric Stimulation; D004576:Electromyography; D019054:Evoked Potentials, Motor / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000503:physiopathology*; D009431:Neural Conduction / Q000502:physiology; D009468:Neuromuscular Diseases / Q000150:complications* / Q000473:pathology; D018709:Statistics, Nonparametric