title: Various aspects of F-wave values in a healthy population.
abstract: OBJECTIVE
  To characterize various aspects of F-wave in a healthy population and establish normative data for future clinical use.
  
  
  METHODS
  A total of 100 healthy volunteers underwent sensory and motor nerve conduction studies of the ulnar and tibial nerves, including F waves elicited by 32 stimuli.
  
  
  RESULTS
  The F-wave measurements (mean +/- SD for ulnar vs tibial nerve) consisted of persistence (83 +/- 19 vs 97 +/- 5%), minimum, mean and maximum latencies (26.5 +/- 2.1, 28.1 +/- 2.2, and 30.4 +/- 2.3 vs 47.0 +/- 4.1, 49.6 +/- 4.4, and 52.5 +/- 4.4 ms), minimum, mean and maximum F-wave conduction velocities (FWCV) (55.0 +/- 2.7, 60.0 +/- 2.3, and 64.0 +/- 3.0 vs 49.0 +/- 2.9, 52.2 +/- 3.1, and 55.5 +/- 3.4 m/s), chronodispersion (3.9 +/- 0.9 vs 5.5 +/- 1.4 ms), mean amplitude (347 +/- 152 vs 384 +/- 148 microV) and mean duration (8.6 +/- 2.9 vs 13.0 +/- 4.5 ms). Additional measures, registered by electronic averaging, included latency (27.4 +/- 2.3 vs 48.6 +/- 4.7 ms), duration (9.6 +/- 2.2 vs 16.4 +/- 4.2 ms), and amplitude (299 +/- 156 vs 208 +/- 116 microV).
  
  
  CONCLUSIONS
  The use of a height nomogram serves well as an acceptable means to adjust F latencies for the limb length. In addition to the commonly used minimal latency, maximal FWCV, and persistence, clinically relevant measures with a narrow variability includes mean and maximal latencies, chronodispersion, and mean duration. In particular, mean latency obtained with 10 stimuli gave accurate results either for group or individual analysis.
  
  
  CONCLUSIONS
  The data help establish an adequate manner of recording F-wave latencies in clinical evaluation.
authors.affiliation: Laboratory of Clinical Neurophysiology, Federal University of São Paulo, São Paulo, SP, Brazil. jamnobrega@aol.com
authors.forename: João Antonio Maciel
authors.initials: JA
authors.lastname: Nobrega
authors.forename: Denise Spinola
authors.initials: DS
authors.lastname: Pinheiro
authors.forename: Gilberto Mastrocola
authors.initials: GM
authors.lastname: Manzano
authors.forename: Jun
authors.initials: J
authors.lastname: Kimura
mesh_terms: D000293:Adolescent; D000328:Adult; D001827:Body Height / Q000502:physiology; D004558:Electric Stimulation; D004576:Electromyography; D005121:Extremities / Q000033:anatomy & histology / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009431:Neural Conduction / Q000502:physiology*; D012016:Reference Values; D013979:Tibial Nerve / Q000502:physiology; D014459:Ulnar Nerve / Q000502:physiology