title: Simulation studies on the motor unit potentials with satellite components in amyotrophic lateral sclerosis and spinal muscle atrophy.
abstract: BACKGROUND
  We compared motor unit potentials (MUPs) with satellite components recorded in two anterior horn disorders: amyotrophic lateral sclerosis (ALS) and spinal muscular atrophy (SMA, types II and III).
  
  
  METHODS
  We analyzed MUPs recorded from biceps brachii muscle, including 209 associated with ALS (12 patients) and 127 with SMA (5 patients). Simulations were applied to determine the origin of satellites in these processes.
  
  
  RESULTS
  MUP parameters differ in ALS and SMA. Simulations indicate that the satellite potential in ALS often originated from a single fiber, whereas in SMA it originated from a group of fibers of smaller diameters than the surrounding ones.
  
  
  CONCLUSIONS
  These results suggest that, except for neurogenic factors, the variability of muscle fiber diameters also leads to the formation of MUPs with satellites. This variability seems to be responsible for the differences in the shape of the main and satellite MUP components in ALS and SMA.
authors.affiliation: Nałȩcz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, Trojdena 4, 01-109 Warsaw, Poland. ewa.zalewska@ibib.waw.pl
authors.forename: Ewa
authors.initials: E
authors.lastname: Zalewska
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Rowinska-Marcinska
authors.forename: Małgorzata
authors.initials: M
authors.lastname: Gawel
authors.forename: Irena
authors.initials: I
authors.lastname: Hausmanowa-Petrusewicz
mesh_terms: D017668:Age of Onset; D000368:Aged; D000690:Amyotrophic Lateral Sclerosis / Q000503:physiopathology*; D002452:Cell Count; D048430:Cell Shape; D048429:Cell Size; D003198:Computer Simulation; D004576:Electromyography; D055724:Electrophysiological Phenomena; D005071:Evoked Potentials / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009046:Motor Neurons / Q000502:physiology*; D018485:Muscle Fibers, Skeletal / Q000502:physiology*; D009134:Muscular Atrophy, Spinal / Q000503:physiopathology*; D032496:Satellite Cells, Skeletal Muscle / Q000502:physiology*