Magnetic stimulation using a triple-stimulation technique in patients with multifocal neuropathy without conduction block

Muscle Nerve. 2005 Dec;32(6):710-4. doi: 10.1002/mus.20434.


It has been suggested previously that multifocal motor neuropathy (MMN) without conduction block (CB) or other features of demyelination is axonal in nature. Conventional transcranial magnetic stimulation (TMS) and the triple-stimulation technique (TST) performed on 10 MMN patients without CB revealed a proximal focal CB in 4 patients. In 3 other patients, the amplitude ratio obtained in response to conventional TMS was abnormally low, but the area ratio was normal. The TST amplitude ratio and area ratio were normal in these 3 patients. This pattern suggested the occurrence of temporal dispersion without CB. The occurrence of temporal dispersion or CB was associated with a relatively satisfactory response to intravenous immunoglobulins. These findings suggest that some forms of MMN previously thought to be axonal are in fact proximal variants of MMN with CB.

Publication types

  • Clinical Trial
  • Comparative Study

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Amyotrophic Lateral Sclerosis / diagnosis
  • Amyotrophic Lateral Sclerosis / physiopathology
  • Electric Stimulation / methods*
  • Electromyography / methods
  • Evoked Potentials, Motor / radiation effects
  • Female
  • Follow-Up Studies
  • Humans
  • Magnetics*
  • Male
  • Middle Aged
  • Motor Neuron Disease / diagnosis*
  • Motor Neuron Disease / physiopathology*
  • Neural Conduction / physiology*
  • Peripheral Nervous System Diseases / diagnosis*
  • Reaction Time / physiology
  • Reaction Time / radiation effects