What is an Electroencephalogram (EEG)?
An Electroencephalogram (EEG) is a non-invasive diagnostic test that measures and records the electrical activity of the brain. It is commonly used to detect abnormalities in brain waves or brain function.
We perform routine EEG testing to assess brain wave activity in patients experiencing seizures,
confusion, or other neurological symptoms. Our EEG study helps pinpoint abnormalities in brain function for accurate diagnosis and treatment planning.
Key Facts About EEG:
| Feature | Details |
|---|---|
| Purpose | To assess electrical activity in the brain and help diagnose neurological conditions. |
| What it Measures | Brain wave patterns (electrical impulses) from neurons in the cerebral cortex. |
| How it’s Performed | Small sensors (electrodes) are placed on the scalp to record brain signals. |
| Pain Level | Completely painless and non-invasive. |
| Duration | Usually 20–40 minutes (can be longer for continuous monitoring). |
Why Is an EEG Done?
EEG is used to diagnose or monitor conditions like:
- Epilepsy and other seizure disorders
- Sleep disorders (e.g., narcolepsy)
- Encephalopathies (brain dysfunction)
- Brain infections (e.g., encephalitis)
- Head injuries
- Brain death (in ICU settings)
- Monitoring during surgery or in coma patients
Types of EEG:
| Type | Description |
|---|---|
| Routine EEG | Standard test done in a clinic, usually 20–40 minutes. |
| Ambulatory EEG | Carried out over 24–72 hours while the patient goes about daily life. |
| Video EEG Monitoring | Continuous EEG with video recording to correlate brain activity with physical behavior (often used for epilepsy diagnosis). |
| Sleep EEG | Performed while the patient is asleep or during sleep deprivation. |
What EEG Results Show:
| Brain Wave Type | Frequency | Associated State |
|---|---|---|
| Delta | 0.5–4 Hz | Deep sleep |
| Theta | 4–8 Hz | Drowsiness, light sleep |
| Alpha | 8–13 Hz | Relaxed, awake |
| Beta | 13–30 Hz | Alert, active thinking |
| Gamma | >30 Hz | High-level cognition (rare in clinical EEG) |
Abnormal patterns, such as spikes, sharp waves, or slow waves, may indicate epilepsy or other brain disorders.
Patient Experience
- You’ll sit or lie down while the technician applies electrodes with conductive gel or paste to your scalp.
- You may be asked to open/close your eyes, breathe deeply, or respond to flashing lights.
- There’s no pain, but the gel may feel cool or sticky.