Measurement of sleep.

Rapid eye movement (REM) and non-REM sleep processes affect the electrical signals from brain, eyes and muscles. Recording these signals during sleep imposes special demands on electrodes, technicians and equipment. Both human and computerized signal analysis can then be applied to quantify the sleep processes. The most practical and state-of-the-art recording and analysis methods are discussed with emphasis on the most important details. Other analysis methods can be judged based on a few simple criteria.