What is the role of EOG channels in polysomnography (PSG)?

Updated: Apr 29, 2020
  • Author: Carmel Armon, MD, MSc, MHS; Chief Editor: Arlen D Meyers, MD, MBA  more...
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Answer

Answer

Two EOG channels are used to monitor both horizontal and vertical eye movements. Electrodes are placed at the right and left outer canthi, one above and one below the horizontal eye axis. The electrodes pick up the inherent voltage within the eye; the cornea has a positive charge and the retina has a negative charge. Evaluation of the eye movements is necessary for 2 reasons. First is for documentation of the onset of rapid eye movement (REM) sleep, and second is to note the presence of slow-rolling eye movements that usually accompany the onset of sleep.


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