Open-loop and closed-loop optokinetic nystagmus (OKN) in myasthenia gravis and nonmyasthenic subjects

Exp Neurol. 2000 Nov;166(1):166-72. doi: 10.1006/exnr.2000.7503.

Abstract

Optokinetic nystagmus (OKN) eye movements of myasthenia gravis (MG) and nonmyasthenic ocular palsies, and normal subjects were examined under closed-loop and open-loop conditions. The open-loop OKN condition was achieved by adding the signal of eye-movement velocity of OKN to the computer-generated signal controlling the stimulus grating moving. The OKN was recorded by means of electromagnetic search scleral coil technique. In MG patients, the open-loop gains of OKN increased significantly after the intramuscular injection of an acetylcholinesterase inhibitor, neostigmine, while the closed-loop OKN gains were not significantly changed. Both the closed-loop and open-loop OKN gains of normal subjects and nonmyasthenic patients were not increased for the administration of neostigmine. The experimental results indicated that the open-loop OKN gain could be sensitive to reflect the changes of the function of neuromuscular junction in MG patients.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Female
  • Humans
  • Male
  • Middle Aged
  • Myasthenia Gravis / complications*
  • Myasthenia Gravis / diagnosis
  • Myasthenia Gravis / physiopathology
  • Neostigmine / pharmacology
  • Neuromuscular Junction / drug effects
  • Neuromuscular Junction / pathology
  • Neuromuscular Junction / physiopathology
  • Nystagmus, Optokinetic / drug effects
  • Nystagmus, Optokinetic / physiology*
  • Ocular Motility Disorders / diagnosis
  • Ocular Motility Disorders / etiology*
  • Ocular Motility Disorders / physiopathology
  • Oculomotor Muscles / drug effects
  • Oculomotor Muscles / pathology
  • Oculomotor Muscles / physiopathology

Substances

  • Neostigmine