title: Clinical utility of F wave parameters in unilateral S1 radiculopathy.
abstract: OBJECTIVE
  To investigate the F wave parameters (F duration, F minimum latency, F maximum latency, F mean latency, F chronodispersion, and F persistence) of the tibial nerve with unilateral S1 radiculopathy. We evaluated the differences of these parameters between the affected and unaffected sides and also with the control group.
  
  
  METHODS
  The study was performed from September 2007 to January 2008 in the Electrophysiology Laboratory of Marmara University Medical Faculty, Istanbul, Turkey. Bilateral tibial F waves were obtained from 20 normal control subjects (control group) and 20 patients with unilateral S1 radiculopathy (patient group). Minimum, maximum, and mean F latency values were corrected by the subject`s height (F min/H, F max/H, F mean/H). Needle electromyography was performed in the patient group. The patients with a history of diabetes, alcoholism, or other abnormality known to affect peripheral nerves were excluded.
  
  
  RESULTS
  In the control group, no significant differences were found in any of the F-wave parameters between the 2 sides. In the patient group, there were significant prolongations of F duration, F min/H, F max/H, F mean/H, and F chronodispersion on the lesion side. Patients` F durations of the affected and unaffected side were significantly longer than the control group. The F chronodispersion also showed significant prolongation on the affected side in the patient group compared with the control group. Among 20 patients, 15 had evidence of denervation or polyphasic potentials on needle electromyography.
  
  
  CONCLUSIONS
  The F wave study can be clinically useful in the evaluation of S1 radiculopathies, especially in patients with mild and early stage of the disease. Both F duration and F chronodispersion have a higher diagnostic value as compared to F min in the diagnosis of lumbosacral radiculopathy, especially in cases with normal findings on needle electromyography.
authors.affiliation: Department of Neurology, Haydarpasa Numune Training and Research Hospital, Uskudar, Istanbul, Turkey. mgencer15@yahoo.com
authors.forename: Mehmet
authors.initials: M
authors.lastname: Gencer
authors.forename: Kayihan
authors.initials: K
authors.lastname: Uluc
authors.forename: Yilmaz
authors.initials: Y
authors.lastname: Cetinkaya
authors.forename: Baris
authors.initials: B
authors.lastname: Isak
authors.forename: Hulya
authors.initials: H
authors.lastname: Tireli
authors.forename: Onder
authors.initials: O
authors.lastname: Us
authors.forename: Tulin
authors.initials: T
authors.lastname: Tanridag
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D004576:Electromyography / Q000379:methods; D005260:Female; D007839:Functional Laterality; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009431:Neural Conduction / Q000502:physiology*; D011843:Radiculopathy / Q000473:pathology / Q000503:physiopathology*; D011930:Reaction Time; D013979:Tibial Nerve / Q000503:physiopathology; D055815:Young Adult