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.
Tian
Jing
J
Laboratory of Neurobiology of Shanghai Institute of Physiology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yue-Yang Road, China.
Yang
Qing
Q
Wei
Min
M
Terdiman
Joseph
J
Sun
Fuchuan
F
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