VERTICAL EYE-MOVEMENT DURING REM SLEEP: EFFECTS OF AGE AND ELECTRODE PLACEMENT

ABSTRACT All‐night sleep studies were carried out in young adults and aged normal subjects. Eye‐movement (EM) was recorded as electro‐oculogram from each subject with two different electrode placements. In young adults a placement which responded to vertical as well as to horizontal EM yielded scores for EM activity about one‐third greater than those obtained with a placement which responded only to horizontal movements. In addition, the two placements differentially affected estimates of stage 1 EEG. These effects were less marked in aged subjects who were found to have fewer vertical EMs than young adults. It was hypothesized that the proportion of vertical eye‐movement reflects the intensity of REM sleep processes.