title: Stimulation of Cauda Equina With a Figure-of-Eight Magnetic Coil.
abstract: OBJECTIVE
  To record responses in the abductor hallucis muscle after lumbosacral stimulation with a figure-of-eight magnetic coil. To compare magnetic stimulation (MS), electrical stimulation (ES), and the peripheral motor conduction time.
  
  
  METHODS
  M and F waves and compound muscle action potentials were recorded after L1 MS, S1 MS, and L1 ES.
  
  
  RESULTS
  The compound muscle action potential latency on L1 MS was 26.9 ± 2.6 milliseconds and on L1 ES was 25.6 ± 2.2 milliseconds, and the peripheral motor conduction time was 27.0 ± 2.5 milliseconds (analysis of variance P = 0.0008). The compound muscle action potential amplitude was 12 ± 11% of M-wave on L1 MS, 32 ± 18% on S1 MS, and 31 ± 17% on L1 ES.
  
  
  CONCLUSIONS
  Dorsal MS reliably elicits responses in the abductor hallucis muscle. The latency of compound muscle action potentials on L1 MS is comparable to peripheral motor conduction time. A potential drawback of MS may be too weak stimulation at the proximal end of the cauda equina.
authors.affiliation: Institute of Clinical Neurophysiology, University Medical Centre Ljubljana, Ljubljana, Slovenia.
authors.forename: Ana
authors.initials: A
authors.lastname: Golež
authors.forename: Zoran
authors.initials: Z
authors.lastname: Rodi
mesh_terms: D000328:Adult; D000368:Aged; D002420:Cauda Equina / Q000502:physiology*; D004558:Electric Stimulation / Q000379:methods*; D004576:Electromyography; D019054:Evoked Potentials, Motor / Q000502:physiology*; D005260:Female; D006801:Humans; D008280:Magnetics; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000294:innervation; D009431:Neural Conduction; D010523:Peripheral Nervous System Diseases / Q000175:diagnosis / Q000503:physiopathology*; D011930:Reaction Time; D055815:Young Adult