title: Usefulness of cervical root magnetic stimulation in assessing proximal motor nerve conduction.
abstract: OBJECTIVE
  To evaluate the reliability and utility of cervical root magnetic stimulation in exploring proximal motor conduction.
  
  
  METHODS
  In 20 patients with demyelinating polyneuropathy (DPN), 20 patients with amyotrophic lateral sclerosis (ALS) and 25 healthy subjects, evoked compound muscle action potentials (CMAPs) were recorded from abductor digiti minimi muscle in response to electrical stimulation up to Erb's point and magnetic stimulation up to the cervical roots.
  
  
  RESULTS
  In all healthy and ALS subjects, magnetic root stimulation confirmed the absence of conduction abnormalities, including those in whom supramaximal responses at Erb's point were not achieved. In the DPN group, conduction block and/or temporal dispersion was revealed by magnetic root stimulation in 9 out of 20 patients (45%), 3 more than those detected at Erb's point.
  
  
  CONCLUSIONS
  Cervical root stimulation allowed clear distinction between motor neuronopathy and DPN. It is recommended as part of the routine evaluation of patients suspected of having DPN, especially when distal nerve studies are inconclusive.
authors.affiliation: Department of Neurology, School of Medicine, University of Patras, Patras, Greece.
authors.forename: Dimitra
authors.initials: D
authors.lastname: Veltsista
authors.affiliation: Department of Neurology, School of Medicine, University of Patras, Patras, Greece. Electronic address: echroni@yahoo.com.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Chroni
mesh_terms: D000328:Adult; D000368:Aged; D000690:Amyotrophic Lateral Sclerosis / Q000175:diagnosis* / Q000503:physiopathology; D004558:Electric Stimulation; D004576:Electromyography / Q000379:methods*; D005260:Female; D006801:Humans; D008280:Magnetics; D008297:Male; D008875:Middle Aged; D009046:Motor Neurons / Q000502:physiology; D009103:Multiple Sclerosis / Q000175:diagnosis* / Q000503:physiopathology; D009431:Neural Conduction; D013126:Spinal Nerve Roots / Q000502:physiology*
keywords: Amyotrophic lateral sclerosis; Cervical root stimulation; Demyelinating polyneuropathy; Magnetic stimulation; Motor nerve conduction