An Electrooculographic Method for the Evaluation of Psychotropic Drugs on Saccadic Eye Movements in Healthy Subjects

Recording of saccadic eye movements has proved to be a valuable tool for investigation of brain function anddysfunction and is very sensitive to centrally acting drugs. Since there is a lack of agreement concerningvelocity–amplitude characteristics of saccadic eye movements, the present study obtained saccadic eyemovements from 24 healthy subjects using indigenously developed electro-oculographic recording and analysissystem in forward and countdown sequence. The validity of the system was further tested by evaluating thepsychotropic effects of 5mg zolpidem and 500mg caffeine in randomized, double blind, placebo controlled threeway cross over design on 24 healthy subjects. Saccadic eye movements were measured at baseline and 1, 2 and 3hrs after administration of study medication. Mean (±SD) values for peak saccadic velocity (PSV) over saccadesof ±10, ±20, ±30, ±40, ±50 & ±60 degrees were in agreement with those previously reported. Zolpidemproduced statistically significant decrease in PSV compared to placebo at all the angular displacements at 1 & 2hrs. In contrast, caffeine produced non-significant increase in PSV at all angular displacements at 1hr. Similarlylatency period (LP) increased with zolpidem and decreased with caffeine compared to placebo. Theelectro-oculographic recording and analysis system is simple, sensitive to centrally acting drug effects andtherefore has potential for future experimental psychomotor assessment studies.