Wada Test
The intracarotid amobarbital test or Wada test (named after Dr. Juhn Wada,
its originator), is part of the presurgical evaluation in a patient who may
have epilepsy surgery. A thin plastic tube ("catheter") is inserted into an
artery at the groin and threaded into other arteries leading to the brain.
The short-acting anesthetic agent sodium amobarbital is injected into an
internal carotid artery (the large artery on the side of the neck going to
the brain), thus putting that side of the brain "to sleep". The patient's
ability to speak, understand speech, and remember things is evaluated. After
the drug effect has worn off, the process is repeated with the other
hemisphere.
The Wada test requires a brief hospitalization. It helps us determine which
cerebral hemisphere is "dominant" for speech and if memory is functional on
one or both sides of the brain. If the seizures are coming from the
nondominant hemisphere, this test may not be needed.