Polysomnography is a comprehensive test that monitors various physiological signals during sleep to diagnose sleep disorders. It typically records brain waves (EEG), eye movements (EOG), heart rate, muscle activity (EMG), breathing patterns, and oxygen levels in the blood (through a pulse oximeter). Blood glucose levels, however, are not part of standard polysomnographic measurements, as they do not directly impact the sleep assessment process. Instead, blood glucose monitoring is relevant to conditions like diabetes, which are outside the scope of a sleep study.