Effect of Transdermal Scopolamine on Induced Nystagmus

Abstract

Transdermal scopolamine (TTS-scopolamine) in the acute attack phase of Meniere's disease has been proved in our previous reports to be effective in alleviating vertigo and nausea. The effect of TTS-scopolamine on evoked nystagmus was evaluated in this study.Ten healthy adult volunteers, five male and five female, with a mean age 28.2 were examined. First, the following tests were performed : optokinetic nystagmus, rotatory induced nystagmus and caloric nystagmus. Optokinetic stimuli were given in 4°/sec2 in 30sec acceleration and deceleration each, without a pause. Rotatory induced nystagmus was provoked with acceleration and deceleration, first 60°/sec rotation in 0.5sec and deceleration in 30sec to standstill without a pause. Caloric stimulation was irrigation with 20°C for 20sec. Nystagmus was analyzed by counting the total number of beats, slow phase velocity and duration.After the application of two sheets of TTS-scopolamine over the mastoids the above procedures were repeated.TTS-scopolamine had no significant effect on any form of nystagmus, although the vertiginous sensation and nausea elicited with caloric stimmuli were decreased in most subjects. Although the present results did not clearly demonstrate an inhibitory effect on vestibular nuclei, TTS-scopolamine might partially block the pathway from the vestibular system to the central autonomic center.