What does EEG measure during a sleep study?

During a sleep study, EEG (electroencephalogram) measures brain wave activity. This measurement is crucial for understanding different sleep stages, including REM (rapid eye movement) and non-REM sleep. The brain generates electrical impulses, and the EEG captures these signals, which reflect the level of brain activity at any given time during sleep.

This information is vital for diagnosing sleep disorders, as variations in brain wave patterns can indicate conditions such as insomnia, sleep apnea, and narcolepsy. Each stage of sleep has a distinct pattern of brain wave activity, which helps polysomnographic technologists analyze and interpret the overall sleep architecture of the patient.

The other options provided do not pertain specifically to what EEG measures; respiration rate, heart rate, and body temperature are monitored through different sensors in a polysomnography study, but they do not involve the measurement of brain activity itself.