Q.______ is useful in diagnosis of neurological and sleep disorders.

EEG (electroencephalogram) records the brain's electrical activity via scalp electrodes and is the standard diagnostic tool for neurological conditions (like epilepsy) and sleep disorders.

EEG works by placing electrodes on the scalp to detect and record the tiny electrical voltage fluctuations produced by neuronal activity in the brain. Because different brain states (wakefulness, various sleep stages, seizure activity) produce characteristic wave patterns, EEG is widely used to:

• Diagnose epilepsy and localize seizure activity.
• Study and diagnose sleep disorders (e.g., in polysomnography during sleep studies).
• Assess brain function after injury, or confirm brain death. …