Descriptive of a technique to diagnose, or to rule out, many types of sleep disorders: The polysomnographic examination involves a technician who observes a patient's sleep activity by looking at a video monitor and the computer screen that displays all the data second by second.

A sleep specialist who monitors sleep studies and records the relevant physiologic variables: After a test is completed, a polysomnographic technologist analyzes the recorded data by checking for breathing irregularities, sudden changes in brain-wave activity, cardiac rhythm abnormalities, leg movements, body positions, and oxygen saturation during the patient's sleep.