An electroencephalogram (EEG) records the brain’s electrical activity via scalp electrodes. It’s used to diagnose and classify seizures and epilepsy, evaluate unexplained fainting, dizziness, confusion or memory problems, assess sleep disorders and encephalopathy, and help monitor brain function during surgery or intensive care. EEG can localize abnormal brain regions and aid treatment planning; it’s noninvasive and often part of neurological workups.

A normal EEG shows age-appropriate, symmetrical brainwave patterns with no epileptiform discharges or focal slowing. In an awake adult you typically see posterior alpha rhythm and faster frontal beta activity; the recording reacts to eye opening and stimuli. Sleep recordings demonstrate expected sleep-stage rhythms. Overall, a normal EEG indicates no electrical evidence of seizure tendency or localized brain dysfunction at the time of testing.

EEG costs vary widely by country, setting and type. In publicly funded systems it’s usually free; private routine EEGs commonly range £150–£800 (UK) or $200–$1,000 (US). Ambulatory or long-term/video EEGs can cost $1,000–$5,000. In India routine EEGs often run ₹500–₹3,000. Final price depends on inpatient vs outpatient care, duration, facility fees and insurance coverage.

An abnormal EEG indicates unusual brain electrical activity and may suggest epilepsy or seizure tendency, encephalopathy, stroke, infection, tumor, or sleep-related disorders. It prompts further evaluation—neurological exam, brain imaging (MRI/CT), blood tests and often prolonged or video EEG monitoring—to identify the cause. Treatment depends on diagnosis and may include antiseizure medication, addressing the underlying condition, and regular follow-up.

An EEG is generally safe and noninvasive. Risks are minimal: mild skin irritation, redness or allergic reaction to electrode paste, discomfort from the cap, and occasional headache or fatigue. Procedures that provoke activity (sleep deprivation, flashing lights) can rarely trigger a seizure. Invasive monitoring (rare) carries higher risks like infection or bleeding. Serious complications are uncommon.

Wear comfortable, loose two-piece clothing (button-up top preferred) so electrodes can be placed without removing garments. Avoid metal (zippers, underwire bras, jewelry), hats, hair clips or scarves. Come with clean, dry hair free of spray, gels, oils or heavy conditioner; don’t braid or style tightly. Avoid makeup that can interfere with sensors. Bring a sweater if you get cold.