Clinical use | Electroencephalography

Clinical use

Some pathological changes of the brain can be visualized by means of the EEG. For example, circulatory, attention and sleep disorders can be diagnosed with this method. A special example is the neurodegenerative disease multiple sclerosis.

In the course of the disease, the insulating layer around the nerve cells breaks down, limiting their function as mediators of sensory impressions. The nerve cells then pass on information more slowly and information is lost due to the lack of isolation. The EEG can register the time between the arrival of a stimulus and the actual measurement (latency).

The latency of such sensorily evoked potentials is typically extended in multiple sclerosis. Another classical application example of the EEG is the recording of epileptic seizures. A distinction is made between partial epilepsy, which only affects certain regions of the brain, and generalized epilepsy, which involves the entire brain.

If a seizure occurs, so-called “spike-and-wave” complexes become visible in electroencephalography. These are characterized by a high synchronicity, i.e. high amplitudes in the EEG. Another important application example is the diagnosis of brain death.

In a brain-dead patient no amplitudes are visible in the electroencephalogram. In this case we speak of an isoelectric or zero line EEG. This occurs when the cerebrum, cerebellum and brain stem are inactive and is therefore a clear indication of brain death. Since brain activity cannot be restored even with the most modern machines, it is considered a definitive sign of death.

Costs

Electroencephalography is a relatively inexpensive and short-term diagnostic procedure. The routine examination takes no longer than half an hour and costs between 50 and 100 €. If there is a justified suspicion of a disease, the procedure is covered by the health insurance company.