Electroencephalography (EEG) is composed of two Greek words, “encephalon” (meaning “brain”) and “graphein” (meaning “write”). This is a diagnostic technique to measure the brain’s electrical activity by monitoring voltage fluctuations along the scalp over a period of time.
Brain current flows are recorded from multiple high-conductivity electrodes attached to the scalp with the help of a special gel. Frequency and amplitude of voltage oscillations may vary depending on the patient’s state of rest. This is an exceptionally safe, non-invasive procedure for brain disease diagnosis.
- Paroxysmal Discharges
These changes in the EEG patterns are characteristic in patients prone to epileptic seizures. In this situation EEG is the most important diagnostic tool available. However, in between the seizures EEG patterns may be within the norm, so EEG exam has to be conducted repeatedly during seizure-prone situations. Examples of these situations include periods of insomnia, rapid breathing (hyperventilation) or photostimulation by rapid flashes of light.
- General Changes
Diese bedeutet eine allgemeine Verlangsamung der Hirnströme und kann beispielsweise bei entzündlichen oder stoffwechselbedingten Hirnerkrankungen auftreten und einen Hinweis auf den Schweregrad der Erkrankung geben.
In this case we consider overall reduction in brain voltage conductivity which is usually initiated by an inflammatory process or some metabolic disorder of the brain. This process may also be used to measure the progress of the disease over time.
- Focal Damage
This is a change in the electroencephalographic pattern of the brain waves that signifies localized brain damage resulting from an apoplectic stroke, tumor, or an inflammatory disease.