Electroencephalography (EEG) is an examination, which has a significant importance for neurologists. It is used in diagnostics of many pathological neurological conditions, especially in diagnosis of epilepsy.


The examination lasts only few minutes. The doctor places electrodes on the head of the examined person.  The device contains a large number of electrodes that mounted in a special cap. Each electrode scans a certain area of the brain and records neuroelectric signals that are the represent the main way of communication between the nerve cells. The resulting record includes a number of curves (electroencephalogram) that must be evaluated by the physician The trick is that the curves are individual for each person. Therefore, the doctor does not evaluate the curves, but rather their changes due to certain activities performed  during the examination (e.g. closing and opening eyes).


The procedure does not require any special preparation.


The EEG informs us about brain functions and deviations from normal conditions. It is valuable in diagnostics of epilepsy, which can cause occurrence of some certain abnormal patterns. Specialized centers for diagnosis and treatment of epilepsy may monitor patients for a longer time period, which increases the chance of recording the EEG during an epileptic seizure. Sometimes, the doctors may try to provoke it artificially, for example by sleep deprivation or exposure of the patient to flashing light.


EEG examination has a wide use in sleep labs that are focused on investigation of sleep disorders. Patients are monitored during sleep and their EEG pattern is evaluated to find any disturbances that may decrease the sleep quality.


The only problem is the evaluation of the record requires experienced examiner and that its assessment is to certain extent individual.


The examination is painless and may brings valuable information about the intracerebral processes. In addition, the patient is not exposed to any radiation.


Jiri Stefanek, MD  Author of texts: Jiri Stefanek, MD
 Contact: jiri.stefanek@seznam.cz
 Sources: basic text sources