What type of equipment is primarily used to monitor brain activity during a sleep study?

The primary equipment used to monitor brain activity during a sleep study is the electroencephalogram (EEG). This technology records the electrical activities in the brain, providing essential data on brain waves. During a sleep study, various stages of sleep can be identified based on the distinct patterns that the EEG displays.

EEG sensitivity allows for the detection of the different phases of sleep—such as REM (Rapid Eye Movement) and non-REM sleep. This information is crucial for understanding a patient's sleep architecture and diagnosing sleep disorders.

While polysomnography (PSG) incorporates EEG as one of its components alongside other measures like oxygen levels and heart rate, it is not solely responsible for brain activity monitoring. Electromyography (EMG) and magnetoencephalography (MEG) assess muscle activity and brain magnetic fields, respectively, but are not primarily used for monitoring brain activity specifically in the context of sleep studies. Thus, the electroencephalogram stands out as the direct tool for observing brain activity during sleep.