The Wada test is used in neuropsychology to determine in which certain brain functions are localized. It is named after the Japanese- Canadian Juhn Atsushi Wada neuropsychologists.

Implementation and target

In epilepsy, it may happen that an operation is necessary if medications are not working enough that removes the parts of the affected side of the brain. Which parts can be removed, it can be determined with the Wada test.

Generally, a catheter is set for access to the brain for the test. This passes through the internal carotid artery ( carotid artery ) to the brain. Through the catheter, a contrast agent is injected into the brain in order to make the blood vessels of the brain seen.

Means amobarbital is pumped into one of the hemispheres of the brain, whereby this part is sedated. Whether the function of the brain is really calm, it is checked with a simple test: The patient had raised both arms prior to administration of the agent; in effect of the injected agent then drops one arm down, its associated brain hemisphere had been turned off, the other remains applicable.

Next, the patient will be asked several questions and arithmetic problems, pictures shown and tested his language.

After the anesthetic has subsided, the patient is again asked about the tests:

  • Can he still remember the picture?
  • Does he know the math problem and the solution yet?
  • As was his language during the test and after?

From the replies it can be decided whether the operation can be performed. For example, if the memory severely affected, this suggests that the other half of the brain can not absorb any more memories. The patient would remain after the procedure on the previous memory state and could no longer accept new events in memory.