title: Fasciculations and their F-response revisited: high-density surface EMG in ALS and benign fasciculations.
abstract: OBJECTIVE
  To compare the prevalence of fasciculation potentials (FPs) with F-responses between patients with amyotrophic lateral sclerosis (ALS) and patients with benign fasciculations.
  
  
  METHODS
  In seven patients with ALS and seven patients with benign fasciculations, high-density surface EMG was recorded for 15 min from the gastrocnemius muscle. Template matching was used to search for pairs of FPs with a repetition within 10-110 ms.
  
  
  RESULTS
  Interspike interval (ISI) histograms were constructed from 282 pairs of benign fasciculations and from 337 FP pairs in ALS. Peaks attributable to F-waves were found at latencies of 32 ms (benign) and 35 ms (ALS). Five patients with benign fasciculations and four patients with ALS had FPs with F-waves.
  
  
  CONCLUSIONS
  F-waves of FPs occur in both conditions - therefore they are not diagnostically helpful.
  
  
  CONCLUSIONS
  F-waves confirm the distal origin of FPs for an individual axon. The occurrence of these FPs in a benign condition suggests that the generation of ectopic discharges in the distal axons is not specific to progressive neurodegeneration.
authors.affiliation: Donders Institute for Brain, Cognition and Behaviour, Department of Neurology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands. kleineb@kempenhaeghe.nl
authors.forename: Bert U
authors.initials: BU
authors.lastname: Kleine
authors.forename: Werner A
authors.initials: WA
authors.lastname: Boekestein
authors.forename: Ilse M P
authors.initials: IM
authors.lastname: Arts
authors.forename: Machiel J
authors.initials: MJ
authors.lastname: Zwarts
authors.forename: H Jurgen
authors.initials: HJ
authors.lastname: Schelhaas
authors.forename: Dick F
authors.initials: DF
authors.lastname: Stegeman
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D000328:Adult; D000368:Aged; D000690:Amyotrophic Lateral Sclerosis / Q000175:diagnosis* / Q000503:physiopathology*; D004576:Electromyography / Q000379:methods*; D005207:Fasciculation / Q000175:diagnosis* / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000502:physiology; D011930:Reaction Time / Q000502:physiology