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Wada test

The Wada test helps determine which of the two brain hemispheres is responsible for certain important functions, such as language and memory. This type of test may be necessary before an operation to treat epilepsy. Therefore, the primary purpose of the Wada test is to determine if certain parts of the brain can be removed during epilepsy surgery without harming the patient.

For the Wada test, we insert a catheter from the groin and lead it past the heart into the neck artery that supplies blood to one half of the brain. An anesthetic is then released through the catheter. This inactivates the affected hemisphere of the brain for a few minutes. During this time, speech and memory functions will be tested to see which functions are impaired and therefore located on the inactivated brain hemisphere.

Advantages and disadvantages


  • The Wada test is a very reliable test of and shows which functions are located in one hemisphere of the brain.


  • The Wada test involves accessing an artery and requires a short hospital stay (usually one day). Non-invasive alternatives are available, e.g. functional MRI examination or transcranial magnetic stimulation, but these are less established.

Why choose the USZ?

Many years of expertise

Our clinic is an internationally renowned institution in the field of diagnostics and minimally invasive, image-guided treatment. We treat diseases of the brain, spinal cord, peripheral nervous system, associated organs (eyes, auditory, vestibular, etc.), and surrounding structures of the head, neck and spine.

Latest treatment methods

At the Department of Neuroradiology, we strive to offer the best possible treatment to every patient. We therefore use the latest interventional methods, the most advanced materials and instruments, and cutting-edge imaging techniques.

Partner network

Additionally, we hold weekly interdisciplinary conferences with experts from neurosurgery, neurology and neuroradiology during which we develop an individual therapy concept for each case. To guarantee optimal treatment selection and patient care our experienced neuroradiology interventionists further collaborate with experts from other clinics as well as with outstanding nursing and rehabilitation specialists before, during and after the intervention.

Course of treatment

You will come to the Department of Neuroradiology in the morning. After informing you about the procedure, we will perform a diagnostic angiogram where we puncture the groin artery and insert a catheter. The catheter is then left in the cervical artery. An anesthetic is released through the catheter and inactivates the affected brain hemisphere for a few minutes. During this time we will test your speech and memory functions to see which functions are impaired to determine if they are located on the inactivated brain hemisphere.


Immediately after the procedure, we will examine you to make sure everything went well. You will then be transferred to a ward and will need to spend a few more hours in bed to prevent bleeding in the groin. In the late afternoon, you will be able to get up, but you should avoid doing sports for another two days.

Hospital stay One day

For patients

As a patient, you cannot register directly for a consultation. Please get referred by your primary care physician or specialist. If you have any questions, please contact our patient secretariat.

Tel. +41 44 255 56 01

For referring physicians

Register your patient for our neurovascular consultation hour through the online form or through an e-mail to the patient secretariat.

Tel. +41 44 255 56 01