Polysomnography Asleep study. It is a multi-parametric test used in the study of sleep as a diagnostic tool in sleep medicine it monitors many body functions including brain functions through electroencephalography eye movements through electrooculography skeletal muscle activation through electromyography in the heart Rhythm through electrocardiography. Copyright Notice Adapted from Wikipedia. Text is available under the  Creative Commons Attribution-ShareAlike License 3.0 ; additional terms may apply.