What parameter is essential in determining sleep stage transitions?

EEG waveforms are crucial in determining sleep stage transitions because they provide vital electrical activity information from the brain. Different stages of sleep, such as REM and Non-REM sleep, are characterized by distinct patterns of brain activity observable through electroencephalography (EEG). For instance, during light sleep, specific theta waves dominate, while delta waves are prevalent during deep sleep. The transitions between these stages can be identified by changes in the frequency and amplitude of these waveforms.

While heart rate variability, respiratory effort, and body temperature variations can provide complementary information about a patient's sleep state, they do not primarily indicate the specific stages of sleep as accurately as EEG waveforms do. Consequently, EEG is the gold standard for determining sleep stages in polysomnography.