Diagnosis

Department of Neurology

Head of Department:
Prof. Dr. med. Dr. h. c. Stefan Schwab

Epilepsy Centre

Spokesman: OA Prof. Dr. med. Hajo Hamer

Pinpointing the seizure focus – localisation diagnostics

This is a diagnostic procedure, the goal of which is to pinpoint an epileptic focus. Investigations aim to discover where in the brain epileptic seizures develop.

According to an international agreement, the following procedures are used:

Video-EEG Monitoring
The patient is continuously monitored with cameras in a monitoring unit and their behaviour is related to the EEG which is recorded at the same time. On the screen, the physician sees the patient on one side and the EEG on the other side, and both are digitally recorded.
more ...

Imaging techniques 
High-resolution imaging helps find the place where seizures develop. Imaging technology is advancing rapidly both in terms of structure (magnetic resonance imaging) and in terms of functionality (positron emission tomography). The Epilepsy Centre has state-of-the-art devices at its disposal. more...

Neuropsychology
Quite often, epilepsy patients also suffer from cognitive functional disorders. With the help of psychological tests it is possible to draw conclusions as to where the epilepsy originates. more...

Wada test
If surgery is planned, the Wada test supplies important information as to what extent there is a risk of memory and speech functions deteriorating and how surgery should be planned to minimise this risk. more...

The goal of localisation diagnostics is to treat drug-resistant epilepsy with epilepsy surgery.
What is known as resective surgery can be performed in the case of unifocal epilepsy, i.e. if there is only one epileptic focus which is responsible for causing seizures. The focus must not be located in eloquent brain areas (e.g. in the speech centre) and must be accessible to a neurosurgeon.

Preoperative diagnosis is a long process which may last several weeks or months. After surgery patients receive follow-up treatment.

Diagnostic process

Patients who have been treated at our outpatient clinic and who may be eligible for surgery are admitted as inpatients to undergo diagnostic examinations. They are monitored, i.e. the patient's behaviour is recorded on camera while brain waves are recorded via surface EEG electrodes attached to the scalp.

Further diagnostic measures are conducted during the inpatient stay, including detailed neuropsychological testing in all cases and a high-resolution magnetic resonance imaging scan of the brain if such a scan has not already been performed.

If required, further imaging scans are conducted.
Functional tests such as the Wada test and MEG, a diagnosis tool which only a few hospitals in Europe have at their disposal, may also be used in this part of the diagnostic process.

If all these procedures are inconclusive, invasive video-EEG monitoring is used where EEG electrodes are implanted on the brain surface beneath the cranial bone by surgery.

A final decision of whether, and if so, which surgical methods are suitable can only be made once all the required diagnostic methods have been completed. The decision is made at the interdisciplinary conference, where medical experts from all relevant fields and psychologists discuss the findings.