This procedure removes a small amount of fluid from the spinal canal so it can be analyzed. All these tests are designed to find out whether the seizure had an underlying cause that may be treated directly. Normal electrical activity makes a recognizable pattern. Seizure-causing changes or irregularities produce different patterns. It's like a polygraph test, except thin wires, called electrodes are pasted on the scalp of the person being tested.
Doctors can often identify the patterns likely to be present when someone has epilepsy.
The recording may also show which part of the brain is affected. Having an EEG is a painless, safe procedure. The machine cannot read your mind or give you an electric shock. It doesn't measure intelligence or reveal mental or emotional illness. It is not used to treat or to cure - just to find out.