title: Influence of spontaneous activity on peak-ratio analysis.
abstract: OBJECTIVE
  To prove or disprove this assumption that in neuropathy patients with abundant spontaneous activity, peak-ratio interference pattern analysis may lead to false negative results.
  
  
  METHODS
  Spontaneous activity >100 microV, automatically analysed by turn/amplitude analysis and expressed as (turns/second)/2 ((T/S)/2), and interference patterns, analysed by the peak-ratio technique, were recorded, one after the other, from the right anterior tibial muscle of 21 patients with neuropathy, aged 36-87 years.
  
  
  RESULTS
  The mean number of spontaneous discharges ((T/S)/2) was 12.3 (range 5.5-26) and its mean amplitude 261 microV (range 146-478 microV). Despite this abundant spontaneous activity, peak-ratio analysis was neurogenic in 81% of the patients. All peak-ratio parameters were independent on the amount and amplitude of spontaneous discharges.
  
  
  CONCLUSIONS
  Spontaneous discharges >100 microV could be adequately assessed by means of the turn/amplitude analysis and did not influence peak-ratio analysis in neuropathies.
authors.affiliation: Ludwig Boltzmann Institute for Epilepsy and Neuromuscular Disorders, Vienna, Austria.
authors.forename: J
authors.initials: J
authors.lastname: Finsterer
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000690:Amyotrophic Lateral Sclerosis / Q000175:diagnosis / Q000503:physiopathology*; D004576:Electromyography / Q000379:methods*; D005260:Female; D006801:Humans; D007866:Leg; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000503:physiopathology; D010523:Peripheral Nervous System Diseases / Q000175:diagnosis / Q000503:physiopathology*; D011129:Polyradiculoneuropathy / Q000175:diagnosis / Q000503:physiopathology*; D012815:Signal Processing, Computer-Assisted