Editing Wada test (section)

==Uses==
The test is usually performed prior to [[Ablative brain surgery|ablative surgery]] for [[epilepsy]] and sometimes prior to tumor resection. The aim is to determine which side of the brain is responsible for certain vital cognitive functions, namely [[Speech communication|speech]] and [[memory]]. The risk of post-operative cognitive change can be estimated, and depending on the surgical approach employed at the epilepsy surgery center, the need for awake [[Craniotomy|craniotomies]] can be determined as well.{{citation needed|date=August 2020}}

The Wada test has several side-effects. Drastic [[Personality alteration|personality]] changes are rarely noted, but [[disinhibition]] is common. Also, contralateral [[hemiplegia]], [[hemineglect]] and shivering are often seen.{{cn|date=January 2023}} After injection on the side of the speech-dominant hemisphere, typically the left, the patient experiences transient [[aphasia]], ie. impaired speech and language or the inability to express or understand language.<ref>{{cite book |last=Luria |first=Aleksandr Romanovich |author-link=Alexander Luria |date=1980 |title=Higher Cortical Functions in Man |edition=2nd |translator-last=Haigh |translator-first=Basil |url= |location=New York, NY |publisher=Basic Books Inc. |page=98 |isbn=0-465-02960-4}}</ref> Though the patient may not be able to talk, sometimes their ability to sing is preserved.{{citation needed|date=August 2020}} This is because music and singing uses a different part of the brain than speech and language.{{citation needed|date=March 2023}} Recovery from the anesthesia is rapid, and EEG recordings and distal grip strength may be used to determine when the medication has worn off. Generally, recovery of speech is dysphasic (contains errors in speech or comprehension) after a language dominant hemisphere injection.{{citation needed|date=August 2020}}

Though generally considered a safe procedure, there are at least minimal risks associated with the [[Angiography|angiography procedure]] that guides the catheter to the internal carotid artery, perhaps related to the physician's experience.{{citation needed|date=August 2020}}  Researchers are looking into non-invasive ways to determine language and memory laterality—such as [[fMRI]], [[Transcranial magnetic stimulation|TMS]], [[magnetoencephalography]], and [[near-infrared spectroscopy]].{{citation needed|date=August 2020}}