title: Utility of minimum F-wave latencies compared with F-estimates and absolute reference values in S1 radiculopathies: are they still needed?
abstract: BACKGROUND
  The utility of F-waves in assessing radiculopathies is debated. The aim of this study is to determine the frequency of abnormal minimum tibial F-wave latencies compared to an F-estimate and an absolute reference value in patients with electromyography (EMG) confirmed S1 radiculopathies.
  
  
  METHODS
  A retrospective review of F-waves in patients with an EMG-confirmed isolated S1 radiculopathy was performed. The minimum and mean latencies of 8 tibial F-waves were compared with the calculated F-estimate and to an absolute reference value, and the frequencies of abnormal responses were determined.
  
  
  RESULTS
  Of the 50 patients with an S1 radiculopathy, 4% had prolongation of the minimum reproducible F-wave latency, and 8% had prolongation of the mean latency relative to the calculated F-estimate.
  
  
  CONCLUSIONS
  The minimum and mean F-wave latencies are infrequently abnormal when compared with an estimated F-wave latency in S1 radiculopathies and are insensitive in the assessment of S1 nerve root injury.
authors: Department of Neurology, Mayo Clinic, 4500 San Pablo Road, Jacksonville, Florida, 32224, USA.
authors: Elizabeth A
authors: EA
authors: Mauricio
authors: Elliot L
authors: EL
authors: Dimberg
authors: Devon I
authors: DI
authors: Rubin
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004568:Electrodiagnosis / Q000379:methods* / Q000706:statistics & numerical data; D004576:Electromyography / Q000379:methods; D004594:Electrophysiology / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009431:Neural Conduction / Q000502:physiology*; D011843:Radiculopathy / Q000175:diagnosis* / Q000503:physiopathology*; D011930:Reaction Time / Q000502:physiology*; D012016:Reference Values; D015203:Reproducibility of Results; D012189:Retrospective Studies; D013979:Tibial Nerve / Q000503:physiopathology*; D013997:Time Factors; D055815:Young Adult
keywords: F-waves; electromyography; latency; nerve conduction studies; radiculopathy