Two Types of Ocular Motility Occurring in Sleep

Abstract

Observations on 27 subjects revealed 2 types of eye movement during sleep. Slow, drifting eye movements occurred during relaxation, at the onset of sleep, and after each body stir during sleep. Mean duration for periods of complete ocular quiescence was approximately 25 minutes. Slow movements never occurred in conjunction with delta brain waves. Rapid, jerky, binocularly synchronous eye movements appeared 1-5 hours (3 hours average) after retiring and reappeared approximately 2 hours later, and then again still later depending upon the length of sleep. Each rapid eye movement period endured approximately 20 minutes and was accompanied by a significant acceleration of heart and respiratory rates as well as with a typical low voltage eeg exhibiting prominent theta waves. Rapid eye movements were associated (p < 0.01) with the recall of dreaming and were probably a motor manifestation of visual imagery.