Tests required before your child’s epilepsy surgery · 2019-08-20 · 6 Epilepsy monitoring unit:...

Tests required before your child’s epilepsy surgery

EMU

MRI

MEG

fMRI

EEG

PET

SPECT

NEUROPSYCH ESAM

INVASIVE MONITORING

Table of Contents

3 | Electroencephalogram (EEG) before epilepsy surgery

6 | Epilepsy monitoring unit: Testing with video EEG

9 | Magnetic resonance imaging (MRI) before epilepsy surgery

12 | Functional MRI before epilepsy surgery

14 | Magnetoencephalography (MEG) before epilepsy surgery

19 | Positron emission tomography (PET) scan before epilepsy surgery

22 | Single photon emission computed tomography (SPECT) scan before epilepsy surgery

25 | Neuropsychological assessment before epilepsy surgery

28 | Etomidate speech and memory (eSAM) test before epilepsy surgery

32 | Invasive electroencephalography (EEG) monitoring before epilepsy surgery

Tests Required Before Epilepsy Surgery for Children | 3

Electroencephalogram (EEG) before epilepsy surgery

The first step in preparing for epilepsy surgery isfor your child to have a routineelectroencephalogram (EEG) brain waverecording.

The test takes 60 to 90 minutes. However, ifyour child needs to take a sedative (see below),please allow up to three hours for your hospitalvisit. This allows enough time for the EEG andfor any medicine to wear off before your childgoes home.

Why does my child need an EEG?Neurons (nerve cells in the brain) use electricalsignals to communicate with each other. AnEEG measures this electrical activity to helpyour child’s doctors see more clearly whereseizures start.

Your child may have two EEGs: one while theyare awake and another while asleep. During thetest, electrodes are attached to your child’s scalpto record different patterns of activity in thebrain while your child does simple tasks or has ashort sleep.

The patterns of electrical activity show up aswavy lines on a computer monitor. Doctors aretrained to read these wavy lines to identify whatmight cause a seizure.

Example of an EEG recording

How do I prepare my child for an EEG?Explain what will happen during the EEG inwords your child understands.Make sure your child’s hair is freshlywashed. Check for any signs of head lice andtell the nurse at the hospital if you seeanything.To help the electrodes stay in place during thetest, do not use conditioner or stylingproducts in your child's hair after you wash it.

Will my child need to be sedated for anEEG?An EEG does not hurt, but some children mayneed a mild sedative (medicine to keep themcalm) to help them lie still for the test. The mostcommon sedatives are chloral hydrate or

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melatonin, a natural substance that helpssomeone fall asleep.

If your child needs to take a sedative, they must:

stop eating solid foods eight hours before theteststop drinking milk, formula or other liquidssix hours before the teststop any breastfeeding four hours before theteststop drinking water three hours before thetest.

What happens when my child arrives forthe EEG?1. A technologist will measure your child’s

head and mark it with a wax pencil so theyknow where to place the electrodes.

2. The technologist will clean the markedareas on your child's head with a gel anduse a special paste to attach the electrodesto your child’s scalp. They will then coverthe electrodes with gauze.

3. The technologist will connect the electrodesto the EEG machine.

What happens during an EEG?The technologist will ask your child to sit or,usually, lie on a bed. They may then ask yourchild to do different activities, such as:

breathe deeply for three minutesopen and close their eyeswatch flashing bright lights for a fewminutes.

While your child does these activities, the EEGmachine will continuously record the patterns of

electrical activity in their brain as wavy lines ona computer screen.

May I stay with my child during the EEG?Yes, you will be able to stay with your childduring the test.

Does the test have any risks or sideeffects?There are typically no risks or side effects fromhaving an EEG.

What should I expect after an EEG?Once the test is done, the technologist willremove the electrodes from your child’s scalp.You are then free to go home.

If your child took a sedative, they might besleepy, grumpy and unsteady and will need to bewatched carefully until the medicine wears off(usually about six hours after the test). They canreturn to their usual activities when they arefully alert again.

Your child’s hair may be a little sticky from thepaste that attaches the electrodes to their scalp.You can easily wash the paste away withshampoo and water.

When will I get the test results?Your doctor will receive the EEG test results anddiscuss them with you and your child at afollow-up appointment, usually about four to sixweeks after the test.

Key pointsAn EEG measures electrical activity in yourchild's brain to help your child's doctors seemore clearly where seizures start.

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During the test, your child will lie still on abed and do different activities whileelectrodes are attached to their scalp to recordthe activity in the brain.If your child needs to take a sedative beforethe test, follow any eating and drinkinginstructions from your child's team.You will be able to discuss the EEG resultswith your child's doctor about four to sixweeks after the test.

At SickKidsIf your doctor has told you that your child needsa sedative for the EEG, a nurse from theneurophysiology department will contact youwith instructions on when your child needs tostop eating and drinking before the EEGappointment.

If the EEG is booked without a sedative but youthink your child will need it, please contact theneurophysiology department a week before theappointment at 416-813-6297.

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Epilepsy monitoring unit: Testing with video EEGAfter an EEG, the next step to prepare yourchild for surgery is to have an epilepsymonitoring unit (EMU) session in the hospital.Your child’s team will give you a date to go tothe hospital and your child will be admitted asan inpatient for a few nights.

The test will last three to five days, dependingon how often your child has a seizure.

Child prepped for epilepsy monitoring unit(EMU) session

Why does my child need a session inthe EMU?The aim of an EMU session is to capture theelectrical activity in your child’s brain during aseizure.

During the session, the electrical activity in yourchild’s brain will be measured using a specialEEG machine that is connected to a videocamera and a microphone. This allows yourchild’s doctors to match the wavy lines on theEEG with your child’s behaviour to try and findout exactly where seizures begin in their brain.

The EMU is a controlled and safe environmentto record your child’s typical seizures. Thedoctors and nurses are there to help control yourchild’s seizures with fast-acting anti-seizuremedication.

How do I prepare my child for an EMUsession?

Explain what will happen during the EMUsession in words your child understands.Pack enough changes of clothes for three tofive days and some enjoyable activities (suchas colouring books, movies, video games ormusic) to keep your child entertained whilethey are in the hospital.Make sure your child’s hair is freshlywashed. Check for any signs of head lice andtell the nurse at the hospital if you seeanything.To help the EEG electrodes stay in place onyour child’s scalp, do not use conditioner orstyling products in your child's hair after youwash it.

What happens when my child arrives forthe EMU session?1. Once your child is admitted to the EMU, an

EEG technologist will measure and markyour child’s scalp with a wax pencil so theyknow where to place the electrodes.

2. The technologist will clean the markedareas on your child's head with a gel anduse special skin glue called collodion toattach the electrodes to your child's scalp.The glue keeps the electrodes on yourchild’s scalp for several days while yourchild is awake and asleep.


3. The technologist will then connect theelectrodes to the special video EEGmachine in the EMU room.

EMU room with camera and computer tocapture seizures

What happens during the EMU session?The EEG electrodes on your child’s scalp willbe attached to a special video EEG machine,which will record the EEG brain wave patterns,video and sound activity.

Just as in a routine EEG, the technologist mayask your child to do different activities, such as:

breathing deeply for three minutesopening and closing their eyeswatching flashing bright lights for a fewminuteshaving the test while sleepy or asleep.

These activities stimulate different types of brainactivity, which in turn create different types ofEEG patterns. They also make a seizure more

likely, which helps your child’s team identifyspecific seizure causes.

The video EEG should generally not hurt, butyour child may feel some pain from the EEGelectrodes pulling on their hair ormay experience skin irritation from the specialglue.

May I stay with my child during the EMUsession?The EMU is a care-by-parent unit, which meansyou can stay with your child during the EMUsession. Your child will also be closelymonitored by nurses and doctors.

Does the test have any risks or sideeffects?Your child will not experience risks or sideeffects from the EMU session. However, there isa risk that your child may have several seizuresduring their stay.

Please be assured that the EMU is a safeenvironment where doctors, nurses andtechnologists can help your child quickly whenneeded.

What should I expect after an EMU stay?Once your child’s team has captured your child’stypical seizure and checked the quality of therecordings, the electrodes will be removed fromyour child’s scalp. Your child will then bereleased from the EMU.

Your child’s hair may be a little sticky from thespecial glue. You can easily wash it away withshampoo and water.

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When will I get the test results?Your doctor will receive the EMU test resultsand discuss them with you and your child at afollow-up appointment within four to six weeks.

Key pointsA session in the epilepsy monitoring unit(EMU) lasts three to five days and allowsyour child's team to record their brain activityand behaviour during a seizure.During the session, your child will be askedto do different activities while EEGelectrodes on their scalp are attached to aspecial video EEG machine.Your child will be carefully monitored bytheir care team. You can also stay with yourchild in the EMU.You can discuss the EMU results with yourchild's doctor about four to six weeks afterthe session.

At SickKidsIf your doctor has told you that your child needsa sedative (medicine to keep them calm) to puton the EEG wires, a nurse from theneurophysiology department will contact youwith instructions on when your child needs tostop eating and drinking before being admittedto the EMU.

If the EMU is booked without arranging asedative, but you think your child will need it,please contact the neurophysiology departmentone week before the appointment at416-813-6297.

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Magnetic resonance imaging (MRI) before epilepsysurgeryA magnetic resonance imaging (MRI) scan usesa strong magnet to take pictures of your child’sbrain.

The MRI scanner is a large, round, noisymachine with a tunnel in the centre. During thescan, your child wears a special helmet and lieson a narrow bed that slides into the MRImachine. The scan does not hurt.

Magnetic resonance imaging (MRI) scan

The MRI scan takes about one hour. However, ifyour child needs a sedative for the scan (seebelow), please allow up to three to four hoursfor your hospital visit. This allows enough timefor the scan and for any medicine to wear offbefore your child goes home.

Why does my child need an MRI scan?The MRI takes picture of your child’s brain.Doctors are trained to look at these pictures toidentify what is the cause of the epilepsy.

How do I prepare my child for an MRIscan?

Explain what will happen during the MRI inwords your child understands.Before the scan, tell the MRI team about anymetal implants inside your child, such asmetal rods, screws, braces or clips, and ifyour child has any body piercings. It isimportant to share this information tominimize the risk of harm from the strongmagnet in the MRI scanner.

Will my child need to be sedated for anMRI scan?Some children may need a sedative (medicine tokeep them calm) to help them lie still for aboutan hour during the scan.

What happens when my child arrives forthe scan?1. An MRI team member will check if your

child can lie still comfortably in the MRImachine.

2. Your child will empty their clothes pocketsand remove any watches, purses, jewelleryand makeup. They can store these in alocker during the scan.

3. Your child will change into a hospital gownand enter the MRI room.

What happens during an MRI scan?The technologist will place your child’s head ina head coil, which is like a helmet. Your childwill also wear earplugs or headphones to helpreduce the loud knocking noise from the MRImachine.

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MRI scan of the brain

Sometimes, doctors may need to give your childa special liquid called contrast to help the MRIimages show more information about the brain.This liquid is put into the vein in your child’shand or arm through an intravenous catheter.

When your child is ready, they will then lie onthe narrow bed that moves into the tunnel. TheMRI technologist will talk to them through aspeaker from outside the MRI room and remindthem to stay still during the whole scan.

If your child is able to stay still without takingany medicine, they may watch a movie to passthe time.

May I stay with my child during the MRIscan?You may stay in the MRI room with your childif:

your child is not asleep during the studythe technologist is sure that it is safe for youto do so, for example by asking about anymetal implants or piercings.

Does the scan have any risks or sideeffects?If your child receives contrast, it may cause arash or puffiness around the face and neck. Thisis very rare, however. The MRI team will watchyour child very closely during and after the MRIto check for any reaction to the contrast and helpease any symptoms.

What should I expect after an MRI?Once the scan is done, your child may getdressed and go home. If your child took anysedative (medicine to help them stay calm)during the MRI, they may leave the hospitalonly when they are alert and fully recovered.

When will I get the test results?Your doctor will receive the report of the MRIscan results and discuss them with you and yourchild at a follow-up appointment, usually aboutfour to six weeks after the scan.

Key pointsAn MRI scan uses a strong magnet to takepictures of your child's brain.Before the scan, tell the team about any metalimplants or piercings in your child to reduceany harm from the magnet in the MRIscanner.

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During the scan, your child will need to liestill in the MRI machine for about an hour.Some children may need a sedative to helpthem with this.You may discuss the results of the MRI scanwith your child's doctor about four to sixweeks after the test.

At SickKidsIf your doctor has told you that your child needsa sedative for the MRI, someone from the MRI

department will contact you with instructions onwhen your child needs to stop eating anddrinking before their appointment.

If the MRI is booked without a sedative but youthink your child needs it, please contact the MRIdepartment at 416-813-5774 and choose option3.

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Functional MRI before epilepsy surgeryA functional magnetic resonance imaging(fMRI) scan takes about an hour. It is similar toa standard MRI except that your child will beasked to do simple activities such as listen to astory, play simple word games and tap theirfingers or toes during the scan. While they dothese activities, the machine will find the partsof the brain that handle important functions suchas speech and movement.

Functional magnetic resonance imaging(fMRI) scan

An fMRI scan uses the same machine as aregular MRI.

Why does my child need an fMRI scan?An fMRI will tell the doctor which part of thebrain is responsible for controlling movement orlanguage so that the doctor has a better ideawhere these important areas are located whenplanning epilepsy surgery.

How do I prepare my child for an fMRI?Explain what will happen during an fMRI inwords your child understands.

Like an MRI scan, the fMRI uses a strongmagnet, which may harm your child if theyhave certain metal implants. Before the scan,tell the MRI team about any metal implantsinside your child, such as metal rods, screws,braces or clips, and if your child has anybody piercings. Sharing this information isimportant for minimizing the risk of harmfrom the strong magnet in the MRI scanner.

What happens when my child arrives foran fMRI?1. An MRI team member will check if your

child will be able to lie still comfortablyduring the fMRI scan.

2. Your child will be told about the activitiesthey will do during the test and will have achance to practise some of them.

3. Your child will empty their clothes pocketsand remove any watches, purses, jewelleryand makeup. They can store these in alocker during the scan.

4. Your child will change into a hospital gownand enter the MRI room.

What happens during an fMRI scan?The technologist will place your child’s head ina head coil, which is like a helmet, and may alsogive your child special goggles. Your child mayalso wear earplugs or headphones to help reducethe loud knocking noise from the MRI machine.

When your child is ready, they will then lie onthe narrow bed that moves into the tunnel. Thetechnologist will talk to your child through aspeaker from outside the room and guide themthrough the activities.


The technologist will also remind your child tokeep very still during the fMRI. Even when theyare asked to do a specific activity such astapping their finger, they must keep the rest oftheir body and head very still.

fMRI scan of the brain

The coloured spots show brain activity.

May I stay with my child during the fMRIscan?You may stay in the MRI room with your childif the technologist is sure that it is safe to do so,

for example by asking about any metal implantsor piercings.

Does the fMRI scan have any risks orside effects?There are typically no risks or side effects fromhaving an fMRI.

What should I expect after an fMRI scan?Once the scan is done, your child may getdressed and go home.

When will I get the test results?Your doctor will receive a report of the fMRIscan and discuss the results with you at a follow-up appointment, usually about four to six weeksafter the scan.

Key pointsA functional MRI tells your child's doctorwhich parts of your child's brain controlmovement and language so they can betterplan your child's epilepsy surgery.Before the scan, tell the team about any metalimplants or piercings in your child to reduceany harm from the magnet in the MRIscanner.During the scan, your child will do simpleactivities while they lie in the MRI scanner.You may discuss the results of the fMRI withyour child's doctor about four to six weeksafter the scan.

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Magnetoencephalography (MEG) before epilepsysurgeryA magnetoencephalography (MEG) scanmeasures magnetic signals from the brain. Thescan takes two to three hours, depending on howmuch activity is being mapped.

Magnetoencephalography (MEG) machine

Your child must be sleepy for the MEG scan tomake sure it gathers the best information. If yourchild needs a sedative for the scan (see below),please allow up to three to four hours for yourhospital visit. This allows enough time for the

scan and for any medicine to wear off beforeyour child goes home.

Why does my child need a MEG scan?Cells in the brain give off magnetic as well aselectrical signals. A MEG scan uses specialelectrodes attached to your child’s scalp tomeasure these magnetic signals and pinpoint theabnormal brain activity where your child’sseizures start.

How do I prepare my child for a MEGscan?

Explain what will happen during the MEG inwords your child understands.Make sure your child’s hair is freshlywashed. Check for any signs of head lice andtell the nurse at the hospital if you seeanything.Leave your child’s hair loose for the scan andremove any hair extensions.To help the electrodes stay in place during thetest, do not use conditioner or stylingproducts in your child's hair.Follow the instructions from your child’sMEG team to make sure your child is sleepyor asleep for the scan. You will be told to putyour child to bed later than usual the nightbefore the MEG and wake them up severaltimes during the night. Even if your child istired, do not allow them to sleep on their wayto the scan.Give your child their medication as usual,unless your doctor tells you otherwise.


Will my child need to be sedated for aMEG scan?Yes, some children may need a sedative(medicine to help them keep calm or helpthem sleep).

What happens when my child arrives forthe MEG?1. A technologist will check if your child can

lie still comfortably in the MEG machine.2. Your child will empty their clothes pockets

and remove any watches, purses, jewelleryand makeup. They can store these in alocker during the scan.

3. They will then change into a hospital gownand go into the MEG room.

4. The MEG technologist will then measureyour child’s head and make small marks onthe scalp with a washable marker or pen.They will also make small marks on yourchild’s nose and in front of their ears.

5. They will put electrodes on your child’snose and in front of their ears. Theseelectrodes are connected to the MEGmachine.

6. The technologist will also put EEGelectrodes on your child’s scalp.

What happens during a MEG scan?When your child is ready, the technologist willplace a MEG helmet on their head and yourchild will lie on the MEG bed.

The MEG will be turned on and the helmet willstart to record your child’s brain activity. TheMEG room is quiet during the scan and will alsobe darkened so that your child can fall asleep.

Child resting on MEG bed with their head in theMEG helmet

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The MEG technologist will sit just outside theMEG room and monitor your child through avideo camera.

Your child will have to keep their head stillduring the scan. Depending on the specific partof their brain where your child’s seizures start,they will do one or more of the following tests:

somatosensory evoked fields (SEF)visual evoked fields (VEF)auditory evoked fields (AEF).

Somatosensory evoked fields (SEF) testYour child will have this test if their seizuresstart in the area of the brain that controlssensation. It takes 20 to 30 minutes.

If your child’s seizures start in or near the areaof the brain that controls arm sensation, yourchild will have a small stimulator placed on theirwrist. The stimulator will receive a smallelectrical signal that will make your child’sthumb move or ‘dance’. In turn, this will send amessage to the part of the brain that controlssensation. This stimulation is done on bothwrists and takes about 20 minutes.

If your child’s seizures start in or near the areaof the brain that controls leg sensation, thestimulator will be placed on your child’s innerankle. This time, the small electrical signal willmake the big toe ‘dance’. This stimulation isdone on both ankles and takes about 30 minutes.

During the SEF test a child lies with their headin the MEG machine while a small electricalstimulator is attached to their wrist or ankle

Visual evoked fields (VEF) testYour child will have this test if their seizuresstart in or near the visual area of the brain (thepart that controls sight). It takes about 30minutes.

During the test, your child will look at a screenshowing a moving black and white checkerboard pattern. They will be asked to focus on adot in the centre of the screen while the blackand white squares move. This will send amessage to the part of the brain that processeswhat your child sees.

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During a VEF test a child lies with their head inthe MEG machine while they look a screen witha moving checker board pattern above them.

Auditory evoked fields (AEF) testYour child will have this test if their seizuresstart in or near the auditory part of the brain (thearea that controls your child’s hearing). It takesabout 30 minutes.

During the test, your child will listen to beeps inone ear and white noise in the other ear whilethey lie still in the MEG scanner. Your child willbe asked to concentrate on the sounds. This willsend a message to the part of the brain thatprocesses what your child hears. This test isdone for both ears.

Doctors will study the scan so that they can findthe area of your child’s brain that controlshearing.

May I stay with my child during the MEGscan?The MEG machine is very sensitive and willpick up the brain activity of everyone in theroom. As a result, your child must be in theMEG room alone. You may wait outside theMEG room and see your child on a screen.

Does the scan have any risks or sideeffects?There are typically no risks or side effects fromhaving a MEG scan.

What should I expect after a MEG scan?Once your child completes the SEF, VEF and/orAEF test, the technologist will remove the EEGwires and electrodes. Your child will then have afew round stickers placed on top of their noseand in front of their ears, where the electrodeswere placed. They will then have a short MRIscan, which will take about 10 minutes.

Once all the tests are done, the technologist willremove the stickers from your child. Your childmay then get dressed and leave. If your childtook a sedative, they may leave only when theyare alert and fully recovered.

Your child’s hair may be a little sticky from thepaste that was used to attach the electrodes totheir scalp. You can easily wash it away withshampoo and water.

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When will I get the test results?Your doctor will receive the report of the MEGresults and discuss them with you and your childat a follow-up appointment about four to sixweeks after the scan.

Key pointsA MEG scan measures magnetic signals inyour child's brain to pinpoint where yourchild's seizures start.Your child must be sleepy for the scan tomake sure it gathers the best results.During the scan, your child may have up tothree tests, depending on whether seizuresstart in the part of their brain that controlssensation, sight or hearing.

You may discuss the results of the MEG withyour child's doctor about four to six weeksafter the scan.

At SickKidsIf your doctor has told you that your child needsa sedative for the MEG, someone from the MEGteam will contact you with instructions on whenyour child needs to stop eating and drinkingbefore their appointment.

If the MEG is booked without a sedative but youthink your child needs it, please contact theMEG team at 416-813-5774 and choose option3.

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Positron emission tomography (PET) scan beforeepilepsy surgeryA positron emission tomography (PET) scantakes pictures of the brain’s metabolism (how itbuilds up and breaks down materials) to identifywhere seizures start.

Positron emission tomography (PET)machine

The PET scanner is a large machine with atunnel in the centre. During the scan, your childwill lie on a narrow table that slides into thetunnel.

The scan takes one to two hours, including preparation. If your child needs a sedative (medicineto keep them calm) for the PET scan, pleaseallow up to three hours for your hospital visit.This allows enough time for the scan and for anymedicine to wear off before your child goeshome.

Why does my child need a PET scan?The PET scan will tell the doctor where seizurestarts in the brain. It will provide additionalinformation to clarify or confirm the location ofseizures, especially in patients where other testssuch as EEG or MEG are not clear, when anMRI is normal or when the MRI findings areunclear.

How do I prepare my child for a PETscan?

Explain what will happen during the PETscan in words your child understands.Do not let your child eat, drink or chew gumfor four hours before the test. If your childhas diabetes, contact the PET team for specialinstructions.Give your child any required medication asusual with a small amount of water, unlessyour child’s doctor tells you otherwise.Make sure your child’s hair is freshlywashed. Check it for any signs of head liceand tell the nurse at the hospital if you seeanything.To help the electrodes stay in place during thetest, do not use conditioner or stylingproducts in your child's hair after you wash it.

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Will my child need to be sedated for aPET scan?Some children may need to take a mild sedativeto help them lie still for the full scan.

What happens when my child arrives forthe PET scan?EEG wires attached to scalp

1. Your child will have a small needle prick intheir finger so the nurse can check theirblood sugar level. If the level is too high,the test will be cancelled and you will needto make another appointment.

2. If the blood sugar level is acceptable, yourchild will then be injected with a very smallamount of radioactive liquid. This liquidhelps to show where abnormal metabolismis happening in the brain.

3. The technologist may place EEG electrodeson your child’s scalp.

4. Your child will need to wait about 30 to 45minutes for the injected liquid to flow totheir brain. During this time, they will be in

a quiet, darkened room to let them relax.You are free to wait with them in this room.

5. When this time has passed, the technologistwill ask your child to empty their bladder inthe washroom so that they can liecomfortably during the PET scan.

6. Your child will then go into the PET room.

What happens during a PET scan?During the PET scan, your child will lie insidethe scanner tunnel and will stay very still andquiet while the scanner takes pictures oftheir brain.

The PET scan itself takes about 30 minutes. ThePET technologist will watch the scan through awindow and a TV camera.

PET scan

May I stay with my child during the PETscan?Yes, you may stay with your child during thescan.

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Does the test have any risks or sideeffects?There is a low risk from the radioactive liquidyour child receives for the PET scan. The doseof liquid that is given to your child equals abouttwo to four years of natural backgroundradiation, depending on your child’s age andweight. Your child’s body will break down theradioactive liquid very quickly and pass it out inurine within 24 hours.

The potential benefits of the PET scan outweighany potential risk from the radiation.

PET scan of the brain

What should I expect after the PETscan?When the scan is done, you and your child maygo home.

If your child took any sedative for the PET scan,they may leave the hospital only when they arealert and fully recovered. Afterwards, they mayeat, drink and return to their usual activities.

When will I get the results of the scan?Your doctor will receive the PET scan resultsand discuss them with you and your child at afollow-up appointment, usually four to sixweeks after the scan.

Key pointsA PET scan takes pictures of how the brainbuilds up and breaks down substances toidentify where seizures start.Your child cannot eat, drink or chew gum forfour hours before the scan. The test may becancelled if their blood sugar level is toohigh.During the scan, your child will be injectedwith a tiny amount of radioactive liquid andlie still in the PET scanner while electrodesattached to their scalp record brain activity.You may discuss the results of the PET scanwith your child's doctor about four to sixweeks after the test.

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Single photon emission computed tomography(SPECT) scan before epilepsy surgeryA single photon emission computed tomography(SPECT) scan takes pictures of the blood flowin your child’s brain. When a seizure starts,more blood flows to the brain. The SPECT scanshows the part of the brain where seizures startas a “hotspot” for blood flow.

The SPECT scan is done during your child’sstay at the epilepsy monitoring unit (EMU).Your child will need two types of SPECT scan:

an ictal scan while your child is having aseizurean interictal scan between seizures.

Each scan takes about 45 minutes. When theyare both complete, your child’s team willcompare the different levels of blood flow.

Single photon emission computed tomography(SPECT) machine

Why does my child need a SPECT scan?The SPECT scan will tell the doctor whereseizure starts in the brain. It will provideadditional information to clarify or confirm thelocation of seizures, especially in patients wherethe other tests such as EEG, MEG or PET scanare not clear, when the MRI is normal or whenthe MRI findings are unclear.

How do I prepare my child for a SPECTscan?As the scan is done while your child is stayingin the EMU, you will not need to do any specialpreparation.

Will my child need to be sedated for thescan?Some children may need a sedative (medicine tokeep them calm) to help them lie still during thescan.

Ictal scanAn ictal scan is done while your child is havinga seizure.

What happens before the ictal scan?1. Your child’s team may lower or stop your

child’s epilepsy medication for a short timeduring your child’s EMU stay.

2. A technologist will place EEG electrodeson your child’s scalp.

3. An intravenous (IV) line will be placed inyour child’s arm.

4. As soon as your child starts having aseizure, a small amount of radioactiveliquid will be injected into the IV line. The


radioactive liquid makes the blood floweasier to see.

What happens during the ictal scan?Your child will have the SPECT scan two to fourhours after receiving the radioactive liquidthrough the IV. This scan will show the bloodflow in the brain at the moment the liquid wasinjected.

During the scan, your child must lie very still tomake sure the images are clear.

Interictal scanThis scan shows the typical blood flow in yourchild’s brain. It is also done during your child’sstay in the EMU and may take place before orafter an ictal SPECT scan, usually on a differentday.

Two types of SPECT scans of the brain

May I stay with my child during theSPECT scan?The EMU is a care-by-parent unit, which meansyou can stay with your child during the SPECTscan. Because of the radioactive liquid given to

your child, women who are pregnant or believethey may be pregnant should stay outside thescan room. Another parent or caregiver can staywith your child.

Does the SPECT scan have any risks orside effects?There is a low risk from the radioactive liquidyour child receives for the SPECT scan. Thedose of liquid given to your child equals abouttwo to four years of natural backgroundradiation, depending on your child’s age andweight. Your child’s body will break down theradioactive liquid very quickly and pass it out inurine within 24 hours.

The potential benefits of the test outweigh anypotential risk from the radiation.

What should I expect after a SPECTscan?After a SPECT scan (ictal or interictal), thetechnologist will remove the IV line and theEEG electrodes and wires.

Once your child has recovered from anysedative, they may go back to their normalactivities and eat their usual diet in the hospital.

When will I get the test results?Your doctor will receive the report of theSPECT scan results and discuss them with youand your child at a follow-up appointment,usually four to six weeks after the scan.

Key pointsA SPECT scan is takes pictures of the bloodflow in your child's brain during a seizure.

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The scan takes place during a stay at theepilepsy monitoring unit and has two parts:an ictal scan during a seizure and an interictalscan between seizures.Before an ictal scan, your child's team maylower your child's anti-epileptic drugs for ashort time and inject your child with a smallamount of radioactive liquid to better showblood flow during a seizure.You may discuss the results of the SPECTscan with your child's doctor about four to sixweeks after the test.

At SickKidsIf your doctor has told you that your child needsa sedative for the SPECT scan, someone fromthe nuclear medicine department will contactyou with instructions on when your child needsto stop eating and drinking before the SPECTappointment.

If the SPECT is booked without arranging asedative, but you think your child will need it,please contact the nuclear medicine departmentat 416-813-7654 ext. 206065.

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Neuropsychological assessment before epilepsysurgeryA neuropsychological assessment takes a day toa day and a half, depending on your child's age,and is done by a neuropsychologist or anassistant at the hospital. The assessment uses anumber of tests and observations to measureyour child's thinking, behaviour and problem-solving skills.

Why does my child need aneuropsychological assessment?A neuropsychological assessment is intended tohelp your child’s team:

understand the impact of your child'sneurological (brain) condition on theircognitive functioning (their thinking)plan the best treatment for your child.

When is a neuropsychologicalassessment done?A neuropsychological assessment is done beforeyour child has surgery. It provides baselineinformation about your child's condition and can

help predict if surgery will put your child at riskfor language and memory problems.

Another assessment is done one year aftersurgery to see if there are any changes in yourchild’s thinking, behaviour and problem-solvingskills and to identify areas where your childwould benefit from rehabilitation.

The assessment may also be repeated later to:

record any change in your child's functioningprovide up-to-date information if requiredrecord your child’s functioning at importanttransition points in their life, such as startinghigh school or post-secondary educationhelp with career planning.

How do I prepare my child for theassessment?

Explain the assessment to your child in wordsthey understand. For instance, tell your childthat the testers want to find out how theythink about, learn and remember things.Help prepare a young child by explaining thetests, answering questions and using drawingand special toys such as puzzles and blocks.Prepare an older child by telling them theassessment is like a fun test at school.

Regardless of age, put your child at ease byexplaining that there will be no injections orpainful procedures.

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What types of tests are done during theneuropsychological assessment?Not all tests are done on all children. Thespecific tests will depend on your child's:

agelevel of skillability to co-operateseizure historymedication historybehaviour issuesschool performance.

The assessment measures the following generalskills:

intelligence: your child's overall knowledge,thinking and problem-solving skillsperception: how well your child's brainintegrates information that is coming in, forexample being able to copy shapes that areshown to themmotor function: your child's muscle controlattention: your child’s ability to focus ontasks that continue for some timememory: how well your child learns andremembers new information, for exampleanswering questions about a story they havejust been toldworking memory: the ability to keepsomething in mind while doing another task,for example taking directions to a locationand finding it on a maplanguage skills and vocabulary: the ability tounderstand and use language

concept formation and problem solving: howwell your child solve problems that they havenot seen beforeplanning and organization: how your childplans and organizesprocessing speed: how quickly your child canthinkacademic skills: how well your child canread, write and do basic mathbehaviour, emotions and personality: whetheryour child is depressed or anxious or has anybehaviour problems. This is based on whatthe tester sees during testing as well as anyreports on your child’s behaviour at home orschool.

You may be asked to take part in some of thetests, especially with a young child.

How long does the assessment take?The baseline (first) assessment usually takes afull day, with breaks for rest and lunch. Thelength of the assessment partly depends on yourchild's age and attention level and how fast theycan work. Some children may need to have morethan one appointment across more than one day.

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What should I expect after theassessment?Once the assessment is done, theneuropsychologist will score the tests andinterpret the results in light of your child'smedical history.

The report of your child’s neuropsychologicalassessment will go into your child’s hospitalmedical record and be shared with your child’sepilepsy team when they are discussing yourchild’s condition at team meetings. Outside ofthese situations, your child’s team will treat theinformation as confidential and share it outsidethe team only if required by law.

When will I get the results of theassessment?A few weeks after the assessment, theneuropsychologist will send a report to you andyour referring doctor. You will be able to meetwith a psychologist to discuss the results a fewweeks later.

Key pointsA neuropsychological assessment measuresyour child's thinking, behaviour and problem-solving skills so your child's team can planthe best treatment.In general, the assessment uses tests andobservation to measure things such as yourchild's intelligence, attention, motor function,language skills, memory and behaviour.The assessment generally takes one day, butthe precise length and tests depend on yourchild's age, skill level, seizure history andability to co-operate.Your child will have one assessment beforesurgery and further assessments at set periodsto assess the impact of surgery and recordtheir functioning at important points in theirlife.

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Etomidate speech and memory (eSAM) test beforeepilepsy surgeryThe eSAM test, also known as a Wada test, is aneuropsychological test that requires your childto answer some questions and do some taskswhile half of their brain is “frozen” or put tosleep. They will have an EEG during the test.The test takes about one and a half hours.

To take part, your child will need to be able tolie still and follow instructions for the full test.

eSAM testing room

Why does my child need an eSAM andEEG?An eSAM will tell your child’s doctor whichside of the brain is responsible for speech ormemory. The test is done if your child’s fMRIdoes not provide clear results.

An EEG measures electrical activity in the brainto help your child’s doctors see more clearlywhere seizures start.

Together, the eSAM and EEG will help yourchild’s healthcare team identify which side ofthe brain is important for your child’s speechand memory. This allows them to better planyour child’s surgery so that those areas of thebrain can be left intact.

How do I prepare my child for the eSAMtest?

Explain what will happen during the eSAMtest in words your child understands.Make sure your child’s hair is freshlywashed. Check for any signs of head lice andtell the nurse at the hospital if you seeanything.To help the electrodes stay in place during thetest, do not use conditioner or stylingproducts in your child's hair after you wash it.Your child may need to have an emptystomach for the test. The doctor or nurse willexplain when your child should stop eatingand drinking before the test.

A few days or weeks before the test, your childwill have a set of neuropsychological tests to letthe healthcare team get baseline informationabout your child’s language, cognitive (thinking)skills and memory. Your child’s healthcare teamwill schedule these tests with you and explainwhat is involved.

Will my child need to be sedated beforethe eSAM test?Your child will need to be awake to follow theinstructions during the test, but if they are very


anxious, they can receive a sedative (medicineto help keep them calm).

What happens when my child arrives forthe eSAM test?Before the test, the doctor will explain theprocedure to you and your child.

1. An EEG technologist will place EEGelectrodes on your child’s scalp to monitorthe brain activity during the test.

2. Your child will be asked to lie down on anX-ray table.

3. An interventional radiologist (doctorspecializing in scans and x-rays) will injecta local anaesthetic into your child’s groin.Apart from the prick of the needle, yourchild may feel slight pressure and a mildburning sensation.

4. The radiologist will make a small cut andinsert a thin catheter (tube) into an artery inthe groin so that dye can be injected into thearteries that bring blood to the brain.

What happens during the eSAM test?The test has two parts:

1. an angiogram2. an eSAM test.

1. AngiogramAn angiogram is an x-ray of blood vessels.

Your child’s doctor will inject special dye intoyour child’s artery to help them monitor bloodflow more easily. At first, your child may feelheat or pressure, a metallic taste in their mouthand slight pain. These will all wear off withinminutes.

The blood flow in your child’s brain will then bex-rayed over the following 10 minutes. Yourchild will need to stay still during this time.

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2. eSAM testFollowing the x-rays, your child will receive aninjection of medication called etomidate. Thisputs one half of the brain to sleep but allows theother side to function normally.

Immediately after the injection, your child willnot be able to move one side of their body (theside opposite the location of the injection) andmay not be able to speak.

A neuropsychologist will ask your childquestions to test their language and memory.Depending on how your child answers, and ifthey can answer, the healthcare team will seewhich side of the brain is responsible forlanguage and memory. For instance, if yourchild is unable to speak while the left side oftheir brain is asleep, it will be clear that the leftside of their brain is crucial for languagefunction.

This information will help the team identify thecentres of language and memory in your child’sbrain so they can best plan the epilepsy surgery.

Once the etomidate wears off (usually within 10minutes), the catheter will be moved to theartery that supplies blood to the other side of thebrain. Your child will receive a second injectionof etomidate and the test will be repeated for theother side of the brain.

Does the test have any risks or sideeffects?There are typically no risks from having aneSAM test. However, the dye for the angiogrammay make your child urinate more than usual.

What should I expect after the eSAMtest?As soon as both sides of the brain are tested, theinterventional radiologist will remove thecatheter, apply pressure to stop any bleeding andplace a bandage over the injection site. Yourchild should not normally need any stitches.

Your child may be slightly sore or bruised, butan ice pack can be applied to ease the pain.

Your child will be asked to rest in the hospitalfor several more hours before going home. Ifthey feel nauseous, cold or numb or have astrange sensation in their groin, tell the nurseright away.

As your child may need to urinate more thanusual, give them plenty of fluids over the nextfew hours.

When will I get the test results?Your child’s doctor will use the results of theeSAM test alongside other test results to decideon the best treatment or surgery for your child.When your doctor receives the results, they willdiscuss them with you and your child at afollow-up appointment.

Key pointsAn eSAM, or Wada test, involves answeringquestions and doing tasks while an EEGrecords brain activity and one side of yourchild's brain is put to sleep.The test is divided in two parts: an angiogramto x-ray the blood flow in your child's brainand an eSAM to test your child's languageand memory skills.

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Once the eSAM is done for one side of thebrain, it is repeated for the other side.Your child's doctor will use the results of theeSAM with other test results to decide on thebest treatment or surgery for your child.

At SickKidsYour child will be sedated for the eSAM toallow testing of each half of their brain. You will

receive instructions from the neurology team onwhen your child should stop eating and drinkingbefore the eSAM appointment.

If you have any questions about the test, contactyour child’s neurologist or call the interventionradiology department at 416-813-6054 andchoose option 1 or 3.

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Invasive electroencephalography (EEG) monitoringbefore epilepsy surgeryInvasive EEG monitoring is a test to pinpoint where seizures start in the brain. It is also called invasivesubdural grid/depth and strip epilepsy mapping.

The test involves using a grid of electrodes placed directly on your child’s brain to monitor your child’sbrain activity so doctors can find and record the onset of your child’s typical seizures.

Your child will need brain surgery to place the electrodes and will then be monitored over three to fivedays.

Invasive electroencephalography (EEG) monitoring

A child with EEG electrodes connected to video EEG machine

Why does my child need invasive EEG monitoring?Invasive EEG monitoring is needed if:

the source of your child’s seizures cannot be found with a scalp EEG or other standard brainmonitoring testsseizures occur in parts of the brain that are close to important functional areas, such as areas relatedto speech and hearing.


What happens before my child’s surgery?Once your child is scheduled for invasive EEG monitoring, you will meet your child’s neurosurgeon(who will perform the surgery), the epilepsy neurologist (who will review the EEG data) and epilepsynurse. This team will explain the goals of the surgery to place the electrodes and what to expect before,during and after invasive EEG monitoring. They will also give you a date and time for your child’ssurgery and explain how to prepare your child.

Different types of invasive electrodes

Grid and strip electrodes are placed on the surface of the brain. Depth electrodes are placed into thedeeper parts of the brain.

How do I prepare my child for invasive EEG monitoring?Explain what will happen during invasive EEG monitoring in words your child understands.Make sure your child stops eating and drinking from midnight the night before surgery. If theseinstructions are not followed, the surgery will be cancelled.

What happens when my child arrives for invasive EEG monitoring?When you arrive at the neurosurgery unit, a nurse and an anaesthesiologist will assess your child andprepare them for surgery.

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They will then take your child to the operating room. There, the anaesthesiologist will give your childsleep medicine.

Once your child is asleep, the neurosurgeon will expose your child’s brain and place the special grid ofembedded electrodes on the brain’s surface. Sometimes the surgeon will also place depth electrodes tomonitor deeper parts of the brain.

When all the electrodes are placed, they will be tested to see if they are working and your child's scalpwill then be stitched closed. Your child’s head will then be bandaged and your child will be taken to thecritical care unit for recovery and the start of invasive EEG monitoring.

What happens during invasive EEG monitoring?Your child will be in bed for three to five days while invasive EEG monitoring takes place. Theelectrodes placed on their brain will be connected to a video EEG machine that will continuouslyrecord their brain’s electrical activity and capture any seizures on video.

Does invasive EEG monitoring have any risks or side effects?There are typically no risks or side effects from invasive EEG monitoring.

What should I expect after invasive EEG monitoring?Once all the EEG seizure data has been captured and analyzed, you will meet the epilepsy surgerymonitoring team to discuss the results.

If the source of seizures in your child’s brain is identified, your child will have surgery the next dayto remove the electrodes and remove the area of the brain that is causing their seizures.If doctors cannot find the source of your child’s seizures, they will try again over the following fewdays. If they still cannot find the source, your child will then have the electrodes removed. As it willnot be possible to remove the source of the seizures, you and your child’s healthcare team will usethe information from invasive EEG monitoring to discuss other treatment options.

Key pointsInvasive EEG monitoring involves placing electrodes directly on your child's brain to pinpointexactly where seizures start.Once your child has surgery to place the electrodes, they will be monitored with a video EEG forthree to five days while they stay in the hospital's critical care unit.If the source of the seizures is found, your child will have surgery to remove the electrodes and thearea of the brain that is causing seizures.If the source is not found, the healthcare team will try again and/or use the information to plan othertreatment options.

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At SickKidsIf you have any questions about the test, please contact your child’s neurologist.

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Tests required before your child’s epilepsy surgery · 2019-08-20 · 6 Epilepsy monitoring unit:...

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