Hearing you might need brain surgery – that’s a moment that can stop you in your tracks. So many thoughts, so many questions. And right up there, for many folks I talk to, are the worries: “Will I be the same? Will I still be able to talk like I do now? What about my memories?” These are big, valid concerns. And that’s where a special procedure called the Wada test can really help us all breathe a little easier by giving us vital information before any surgery.
So, What Exactly is This Wada Test?
Okay, let’s talk about this Wada test. It sounds a bit technical, I know, but it’s essentially a way for your medical team to get a clearer picture of your brain before an important surgery, like for epilepsy or a brain tumor. Think of it as creating a personalized map. The main goal? To answer two really important questions:
- Which side of your brain—left or right—is in charge of your language skills?
- How does each side of your brain contribute to your memory?
Knowing this helps your neurosurgeon (that’s your brain surgeon) figure out if there’s a risk to your speech or memory from the planned surgery. It’s all about making the surgery as safe and effective as possible.
This test was first done way back in 1949 by Dr. Juhn Wada, which is where it gets its name. You might also hear it called the intracarotid amobarbital test or sodium amytal test. It’s one of several tools we can use; sometimes, we might also look at functional MRI (fMRI) scans or other specialized evaluations.
Why is the Wada Test Done and Who Might Need It?
The big reason we do a Wada test is to protect your ability to communicate and remember. It’s all about minimizing risks.
You see, for most people, the left side of the brain handles language. But here’s the thing – it’s not true for everyone. This is especially the case for folks who are left-handed. The Wada test helps us confirm which side is your language hub.
When it comes to memory, both sides of your brain play a role. Generally, if your language is on the left, that side is key for remembering words and verbal information (verbal memory), while the right side is more about remembering what you see (visual memory). The test helps us understand which side has stronger memory function overall for you.
Both adults and children can have a Wada test. However, for kids, they need to be old enough to understand what’s happening and participate in the tasks, like identifying words or pictures. A very young child, like a toddler, just wouldn’t be able to do that part.
Getting Ready for Your Wada Test: The Journey
If a Wada test is recommended for you, it’s natural to want to know what’s involved. Let’s walk through it.
The Expert Team Guiding You
You won’t be alone in this. A whole team of specialists works together:
- An epileptologist: This is a neurologist, a doctor specializing in brain conditions, who has extra expertise in epilepsy.
- An interventional neuroradiologist: This doctor is skilled in using tiny tubes called catheters for procedures. They’re the ones who will carefully guide the catheter to the right place in the arteries leading to your brain.
- A neuropsychologist: This specialist understands how brain conditions can affect thinking, behavior, and cognitive skills. They’ll be the one guiding you through the language and memory parts of the test.
Before the Test Day
Your doctor will give you specific instructions. You might need to:
- Stop taking certain medications, like aspirin, some anti-inflammatory drugs (NSAIDs), or blood thinners, for up to two weeks beforehand. But please, keep taking all your regular prescription meds unless your doctor explicitly tells you otherwise!
- Let your team know about any allergies, especially to medications.
On the day, you’ll change into a hospital gown. The team will need to access a blood vessel in your groin area, so that spot will be gently shaved. In the testing room, they’ll also prepare you for an electroencephalogram (EEG) by placing small sensors (electrodes) on your scalp. The EEG lets us see your brain’s electrical activity during the test. It’s painless.
Then, the skin in your groin will be numbed. Once it’s numb, a needle is inserted into a blood vessel in your leg. Through this, a very thin, flexible tube called a catheter is gently threaded up into an artery in your neck – specifically, the carotid artery, which supplies blood to your brain. As this happens, some people notice a funny metallic taste or a warm feeling. You might feel a bit of pressure, but it shouldn’t hurt.
Before the actual Wada test begins, you’ll have an angiogram. This is like a roadmap of the blood vessels in your brain, just to make sure everything looks good for the test.
The Procedure Itself – Step by Step
This is where the “mapping” happens.
- Your interventional neuroradiologist will use the catheter to deliver a small amount of anesthetic (a numbing medicine like amobarbital) into either the left or right carotid artery. This temporarily “puts to sleep” one half of your brain.
- If, say, the right side of your brain is asleep, it can’t communicate with the left side of your body for a short while. You might see stars, feel a bit of pressure behind your eye, or your face might feel warm. You’ll also temporarily lose movement on the opposite side of your body (in this case, the left side). This is all expected, and the EEG helps us confirm that side of the brain is indeed asleep.
- Once one side is asleep, the epileptologist or neuropsychologist will start the testing. They’ll show you cards with words or pictures and ask you to try and remember them. You might find it hard to speak, or feel weak – that’s perfectly normal. Some people even doze off for a moment.
- Sometimes, speaking can be difficult or impossible during this part. We know the test might give us less clear information if a child is younger than 10, if seizures happen during the test, or if someone has an IQ (intelligence quotient) below 70. Your team will be right there to support you if you feel anxious or scared at any point.
- The anesthetic wears off very quickly, usually in just a few minutes. As that side of your brain “wakes up,” the team will ask you what you remember from the cards. If you don’t recall, they’ll show you the cards again and ask if you’ve seen them before. It’s okay if you don’t remember everything!
- After a little while, once you’re fully recovered, the team will repeat the process for the other side of your brain. They’ll gently reposition the catheter to the other carotid artery, do another quick angiogram, and then test the other hemisphere with a new set of cards.
And yes, to answer a common question: you are awake during the Wada test. The whole thing, from start to finish, usually takes about three to four hours. There’s a waiting period between testing each side to make sure you’re completely back to normal before starting again.
After the Wada Test: What’s Next?
Once the test is done, you’ll head to a recovery area to rest. Nurses will check on you regularly, looking at your pulse in the leg where the catheter was and checking the bandage over the tiny incision in your groin. They’ll also make sure your sensation has fully returned. This is all to ensure blood flow in your leg is normal.
Usually, you can go home later the same day. You’ll likely be advised to take it easy and avoid any strenuous activity for 24 to 48 hours.
Now, about safety. The Wada test is generally very safe, but it is an invasive procedure because it involves the catheter. The most common thing people feel afterwards is some soreness where the catheter went in, once the numbing medicine wears off.
Are there risks? Yes, though they are rare. These can include:
- Seizure
- Encephalopathy (a general term for brain dysfunction)
- Stroke
Because it involves entering a blood vessel, there’s also a very small risk of bleeding or infection. This risk, while still low, might be slightly higher if you’re 65 or older, have atherosclerosis (hardening of the arteries), or a history of high cholesterol. We discuss all this with you beforehand, of course.
Understanding Your Wada Test Results
So, what do we learn from all this? The Wada test results are a big piece of the puzzle. They help your medical team pinpoint:
- Which side of your brain is dominant for language.
- Which side is dominant for memory, and how well each side functions.
Your doctors will then look at this information alongside other tests you’ve had, like those showing where seizures might be starting in your brain. Putting all this data together allows your surgeon to understand if there are any particular risks to your language or memory from the proposed surgery, and to plan the safest approach for you. It’s all about tailoring the treatment to your specific brain.
Key Things to Remember About the Wada Test
If you’re considering a Wada test, here are the main takeaways:
- It’s a test done before brain surgery to map out language and memory functions.
- It helps surgeons minimize risks to these vital abilities.
- You’ll be awake, and a team of specialists will guide you through it.
- One side of your brain is temporarily “put to sleep” at a time while you do tasks.
- It’s generally safe, but like any invasive procedure, it has small risks.
- The results provide crucial information for planning your surgery.
This test can give us some really valuable insights. We’ll discuss all the options and what the results mean specifically for you, or your loved one, every step of the way. You’re not alone in this.
