Normal Values:

Brain waves have normal frequency and amplitude, and other characteristics are typical.

What abnormal results mean:

Abnormal findings may suggest the following:

• Seizure disorders (such as epilepsy or convulsions)
• Structural brain abnormality (such as a brain tumor or brain abscess)
• Head injury
• Attention deficit problems
• Encephalitis (inflammation of the brain)
• Hemorrhage (abnormal bleeding caused by a ruptured blood vessel)
• Cerebral infarct (tissue that is dead because of a blockage of the blood supply)
• Sleep disorders (such as narcolepsy)
• Drug or alcohol abuse
• Migraines (in some cases)
• Hallucinations
• Syncope
• Vertigo

EEG may confirm brain death in someone who is in a coma. Note: a normal EEG does not mean that a seizure did not occur.

Additional conditions under which the test may be performed:

• Arteriovenous malformation (cerebral)
• Benign positional vertigo
• Cerebral aneurysm
• Complicated alcohol abstinence (delirium tremens)
• Creutzfeldt-Jacob disease
• Delirium
• Dementia
• Dementia due to metabolic causes
• Febrile seizure (children)
• Generalized tonic-clonic seizure
• Hepatic encephalopathy
• Hepatorenal syndrome
• Insomnia
• Labyrinthitis
• Meniere's disease
• Metastatic brain tumor
• Multiple sclerosis
• Optic glioma
• Partial (focal) seizure
• Partial complex seizure
• Petit mal seizure
• Pick's disease
• Senile dementia (Alzheimer's type)
• Shy-Drager syndrome
• Syphilitic aseptic meningitis
• Temporal lobe seizure