Neostigmine-induced alterations in fast phase of optokinetic responses in myasthenic ocular palsies.
Closed-loop and open-loop optokinetic nystagmus (OKN) eye movements were recorded with an electromagnetic scleral search coil in 16 patients with myasthenic ocular palsies, 8 patients with nonmyasthenic ocular palsies, and 4 normal controls. We calculated the summation of fast-phase amplitude per second (SFPAps), mean of fast-phase amplitude (MFPA) and mean of fast-phase peak velocity (MFPV) of OKN before and after administration of neostigmine. Under open-loop conditions, the myasthenic patients group demonstrated distinct increases in three parameters: SFPAps (P < 0.000001), MFPA (P < 0.001) and MFPV (P < 0.001) following neostigmine injection, and the increase in SFPAps was greater than those of MFPA and MFPV (P < 0.02), while the other two groups showed no significant increases. Under closed-loop condition, only five of the myasthenic patients showed significant changes. These results suggest that the change in SFPAps during open-loop OKN before and after neostigmine administration was a specific measurement that differentiated patients with myasthenic ocular palsies from the other groups.
Laboratory of Neurobiology of Shanghai Institute of Physiology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yue-Yang Road, China.
Jing
J
Tian
Qing
Q
Yang
Min
M
Wei
Joseph
J
Terdiman
Fuchuan
F
Sun
D000293:Adolescent; D000328:Adult; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009157:Myasthenia Gravis / Q000150:complications* / Q000175:diagnosis; D009388:Neostigmine / Q000494:pharmacology*; D017120:Nystagmus, Optokinetic / Q000187:drug effects*; D015840:Oculomotor Nerve Diseases / Q000209:etiology / Q000503:physiopathology*; D010277:Parasympathomimetics / Q000494:pharmacology*
D010277:Parasympathomimetics; D009388:Neostigmine