Introduction
The Wada test is a diagnostic tool that allows physicians to determine the relative relevance of language and memory processes on each cerebral side. The epilepsy team uses the Wada test results to decide which strategy can prevent seizures while protecting brain regions related to memory and speech.
Certain epilepsy and seizure disorders are caused by anomalies in brain tissue, such as tumors, scars, or other lesions, which appear as changes in blood vessels during angiography. Many of these disorders can be treated with epilepsy surgery.
A pre-surgical workup for patients with seizures that are likely to require surgical intervention includes this two-part assessment to determine the potential consequences of surgery on memory and language abilities.
What Is Epilepsy?
Epilepsy is a chronic (long-term) illness marked by repeated seizures caused by abnormal electrical impulses generated by damaged neurons in the brain. An eruption of uncontrolled electrical activity in brain cells causes seizures. Seizures are changes in awareness, muscle control (jerking or twitching), sensations, emotions, or behavior. Epilepsy is capable of developing in individuals of any age, race, or gender.
What Occurs in the Brain During an Epileptic Episode?
Brain cells communicate with and receive signals from many organs in the body. The messages are transmitted via a continuous electrical impulse that travels from one cell to the next. Epilepsy interrupts the normal electrical impulse pattern. Instead, irregular bursts of electrical energy occur between cells in one or more brain areas, comparable to an unpredictable lightning storm. This electrical disruption causes changes in consciousness (including loss of consciousness), sensations, emotions, and muscular activities.
Is Applying the Wada Test Safe?
In general, a Wada test is a low-risk technique. There is a chance of general dangers like discomfort, bleeding, or infection at the catheter insertion site. The Wada test carries a slight risk of certain problems.
These side effects might range in severity from a small soreness at the site of the catheter insertion to a potentially fatal stroke. Given that the Wada requires entering arteries, there's a possibility that fat inside an artery could come loose, obstructing the flow of blood to the brain and resulting in a stroke. Overall, stroke risk is less than one percent. If patients have a history of excessive cholesterol or atherosclerosis (hardening of the arteries) or are older, the amount is higher (but still quite low).
Does Wada Pose a Risk to Health?
Low-risk and risk-free is the Wada test. When the anesthetic wears off, the catheter insertion site will likely experience discomfort if they experience a side effect.
Do Any Hazards or Adverse Reactions Arise?
Uncommon complications consist of:
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Seizure- The chance of having a stroke is less than one percent.
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The sickness is called encephalopathy.
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A stroke would happen.
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Since Wada testing is an invasive process, there is a small chance of getting an infection or bleeding. The rise is only slightly bigger in older people who have atherosclerosis (hardening of the arteries) or have had high cholesterol before.
What Are the Implications of the Tests Result?
Using the Wada test, the treatment team will ascertain which cerebral region is predominant in language processing and which is predominant in memory. A comparison will be made between the obtained information and results from prior diagnostic procedures to ascertain the precise anatomical site of the seizures occurring within the brain. Upon obtaining all pertinent information, the surgeon can determine whether or not the brain surgery poses a risk to memory and communication abilities.
How Is the Wada Procedure Performed?
An anesthetic medicine will be administered through a catheter into either the left or right carotid artery by the neuroradiologist to induce half of the brain to sleep. Medication entering the right carotid artery can disrupt communication between the right side of the brain and the left side of the body. Experiencing those symptoms may include seeing stars, feeling pressure behind the eye, and warmth in the face. They will temporarily experience paralysis on one side of the body. The healthcare specialists will verify the state of the brain's activity by examining the EEG recordings.
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The epileptologist will assess the speech after confirming that one brain hemisphere is inactive.
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Patients may experience speech difficulties and weakness. This is typical. They may also drift off to sleep.
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Children may be nonverbal during the test. Children under ten years old, those with seizures originating from the dominant side of the brain, or individuals with an IQ below 70 are more likely to face difficulties with the test. Healthcare providers will assist children in managing any fear or anxiety.
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The anesthetic will dissipate within a few minutes, allowing the dormant part of the brain to become active again. Subsequently, the epileptologist will inquire about the recollection.
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Eventually, the professionals treating the patient will anesthetize the other hemisphere of the brain. The catheter will be retracted and carefully advanced into the second internal carotid artery. Another angiography will be performed.
What Occurs Following the Recovery?
After the examination, the patient will continue to recuperate in the recuperation unit. The healthcare provider will conduct periodic pulse checks at the location of catheter insertion in the leg. Additionally, the bandages that are obstructing the incision in the genitals will be scrutinized to verify the complete restoration of tactile sensation. These procedures are executed to guarantee adequate circulation in the affected leg.
Conclusion
Wada test findings significantly increase the ability to anticipate changes in language learning and memory performance after surgery. The Wada test is crucial in preoperatively evaluating specific patients with established clinical indications. It helps assess the risks and advantages of epilepsy surgery at an individual level.
Adapting outcome measures and selecting appropriate stimulus material for memory testing during the WT can enhance the assessment of material-specific HML and improve the predictive value of WT results for postsurgical cognitive impairment in clinical practice and future research.
