What physiological activity is assessed using EEG and EOG recordings?

EEG (electroencephalography) and EOG (electrooculography) recordings are specifically designed to assess electrical activity in the brain and the movements of the eyes, respectively. EEG measures the brain’s electrical activity by placing electrodes on the scalp, capturing the brain waves generated by neuronal firing. This is crucial for diagnosing various neurological conditions, understanding brain function during different states of consciousness, and conducting sleep studies.

Simultaneously, EOG is used to record eye movements by detecting changes in electrical potential caused by the shifting movement of the eye muscles. This is particularly important in sleep studies for identifying different sleep stages, especially REM (Rapid Eye Movement) sleep, where significant eye movements occur.

While the other physiological activities mentioned in the choices — cardiac rhythm, muscle activity, and respiratory patterns — are also important in a comprehensive sleep study, they are not assessed with EEG and EOG specifically. Cardiac rhythm is typically measured using ECG (electrocardiography), muscle activity can be evaluated through EMG (electromyography), and respiratory patterns are commonly monitored through various other methods, such as airflow sensors and respiratory belts. Thus, the combination of EEG and EOG is uniquely suited to assess brain and eye movements, which is why