title: In vivo assessment of conduction velocity and refractory period of denervated muscle fibers.
abstract: Stimulation needle electromyography was used to study the muscle fiber conduction velocity and refractory period in 4 patients with long-term denervation of the lower limb muscles due to lesion of the conus cauda or cauda equina (2 untrained and 2 trained by functional electrical stimulation). In untrained patients, the results demonstrated that propagation velocity is reduced and refractory period of the muscle fiber is increased with time of denervation. The patients performing electrical stimulation training showed higher conduction velocities and reduced refractory period despite longer lasting denervation. This suggests that electrical stimulation training is effective to improve the electrical properties of the muscle fiber. Since the obtained data show a good correlation to other clinical tests and biopsy investigations, this method could serve as an additional measurement technique to specify the status of the denervated muscle. Further animal experiments and clinical studies are necessary to proof the results in comparison to more invasive established techniques.
authors.affiliation: Ludwig Boltzmann Institute of Electrical Stimulation and Physical Rehabilitation, Institute of Physical Medicine and Rehabilitation, Wilhelminenspital Wien, Austria. christian.hofer@wienkav.at
authors.forename: Christian
authors.initials: C
authors.lastname: Hofer
authors.forename: Claudia
authors.initials: C
authors.lastname: Forstner
authors.forename: Michaela
authors.initials: M
authors.lastname: Mödlin
authors.forename: Heidrun
authors.initials: H
authors.lastname: Jäger
authors.forename: Winfried
authors.initials: W
authors.lastname: Mayr
authors.forename: Helmut
authors.initials: H
authors.lastname: Kern
mesh_terms: D004558:Electric Stimulation; D004576:Electromyography / Q000379:methods; D006801:Humans; D007866:Leg / Q000294:innervation; D009121:Muscle Denervation; D018485:Muscle Fibers, Skeletal / Q000502:physiology*; D009431:Neural Conduction / Q000502:physiology*; D012032:Refractory Period, Electrophysiological; D013119:Spinal Cord Injuries / Q000503:physiopathology*; D013997:Time Factors