If the protocol is memorized then used the following steps below in order. For more detailed information scroll below to each step's respective part. These are the steps that must be completed before data collection can start.

• Step 1: Set up the laptops and EEG
• Step 2: Measure participant's head
• Step 3: Insert the electrodes/ground into the cap
• Step 4: Insert flat QuickBits into frontal electrodes
• Step 5: Place the cap on the participant
• Step 6: Plug electrode bundle and ground into the amplifier
• Step 7: Open BrainVision Recorder (load workspace)
• Step 8: Check Ground in impedance viewer
• Step 9: Switch to Monitor mode and twist in electrodes
• Step 10: Fix remaining noisy electrodes
• Step 11: Explaining muscle movement artifact to the participant
• Step 12: Remove line noise (make sure nothing is charged)

Here is a list of the following equipment needed to run the EEG experiment.

• Amplifier: The main box that the electrodes are plugged into. It is charged by the battery during EEG recordings.
• Battery: This is the heavier box that powers the amplifier during EEG recordings. It should be connected to a power source at night the day before testing.
• Trigger box: A grey cable that connects the PsychoPy laptop to the amplifier.
• EEG cable: A black cable that connects the EEG laptop to the amplifier.
• Electrodes: They are a bundle of 32 electrodes that are connected to the amplifier on the top slot closes to the participant. The electrodes are screwed into the gears on the cap.
• QuickBits (Tips): Each electrode has a mini tip that can be extended with the placement of three QuickBits(yellow, red, and flat).
• Caps: There are two caps, one for smaller children and one for adolescents. We can measure the circumference of the head to determine which cap is appropriate.
• EEG laptop: The ThinkPad laptop that records the EEG data (password= ackimjr03).
• PsychoPy laptop: The laptop that shows the tasks for the children to do (password= 1001).
• USBc adapter: Is placed into the PsychoPy computer so the trigger box can connect to it. The EEG laptop does not need an adapter.
• EEG dongle: A black USB or flash drive that needs to be connected to the EEG computer for BrainVision Recorder to work. This dongle contains 'BRAIN PRODUCTS' on the front and 'UR12585' on the back. Do not lose this dongle it costs $7,000.
• Tablet: A tablet that contains the 'Inscapes' video.

Amplifier and battery: Place the amplifier (is distinguished by all of the inputs/slots on the top and on its front side) on top of the battery and connect the wire on the back. Always connect and disconnect the black wire, do not mess with the red one.

Front	Back (Disconnected)	Back (Connected)

EEG system: Set up the two laptops. Place the PsychoPy laptop on the left and the EEG ThinkPad laptop on the right. Place the amplifier and battery in between them. Connect the USBc adapter to the PsychoPy laptop and identify the trigger box (grey cable + small black cable with a micro-USB). Connect the trigger box to the PsychoPy computer and to the back of the amplifier. Then identify the black EEG cable and connect it to the ThinkPad and the back of the amplifier. Also insert the BrainVision dongle into the EEG computer. You will know it is working because it will start blinking red.

Now do the same with the EEG cable by connecting it to the EEG computer and the back of the amplifier.

Trigger Box	Back of Amplifier

Below is a picture of the final set up with the PsychoPy computer on the left, the EEG amplifier and battery in the middle, and the EEG computer on the right side (this is an old picture with the previous EEG laptop but the set-up is the same).

Final Set Up

Caps

We currently have two cap sizes:

• M: 48-54
• L/M: 51-57

Each cap contains 32 white gears, 1 black gear and 1 blue gear. All except for the blue gear are important. Each gear has a corresponding black label that informs you which type of electrode goes there, either an electrode numbered 1-32 or the ground electrode.

QuickBits

The QuickBits are the extenders to each electrode. There are three types of Quickbits:

1. Flat
2. Yellow (medium)
3. Red (long)

The Flat QuickBits are used when there is no hair underneath the electrodes, which is usually the case for the electrodes that lay on the forehead. The yellow QuickBits are medium sized and used for the remaining electrodes. The red QuickBits are used rarely- only incorporated when there is too much hair in the way for a yellow QuickBit to make good contact with the scalp (more on this later).

Currently, every electrode except 1, 32, and the ground have the yellow QuickBits in place. This was done on purpose since in 99% of cases this will be the layout used, however, we could theoretically have some of the electrodes 2-31 be red or flat. Electrodes 1, 32, and the ground will almost always have Flat QuickBits.

No QuickBit	Flat QuickBit	Yellow QuickBit	Red QuickBit

Using the information from above, set up the EEG system. This means connect the amplifier to the battery and the cables from the amplifier to the PsychoPy and EEG laptops.

Take a measuring tape and wrap it around the top of the head, then use the value in centimeters to pick the appropriate cap size.

As mentioned these are the two cap sized we currently have:

• M: 48-54
• L/M: 51-57

Pick the cap size that contains the circumference measurement within its range. If the measurement is shared between two caps then go with the smaller cap. Ex: If the circumference is 52, choose the M cap instead of the L/M. However, either can be used.

Sit on a chair and place the electrode bundle splitter box on the back of your neck with the clip making contact with your neck. This will ensure that the electrodes 1-16 are on the left side of you and the electrodes 17-32 are on the right side. Take the cap (you do not need Bob) and position it in front of you with the black gear facing away from you and gears 16, 17, 18 being closest. Take every individual electrode and screw/twist them into the correct gear number about halfway. Make sure the numbers on the tags of the electrodes are the same as the numbers on the gears across the cap. Do not place the wrong electrode in the wrong gear- this error cannot be fixed nor identified in post. When finished, do the same with the ground electrode (black) and twist it into the black gear. Also be gentle with the process- the material is cheap and breaks easily.

To screw in an electrode, place the electrode in its respective gear then turn that gear clockwise with your thumb and index finger while adding a little pressure on the top of the electrode with your other hand.

There are three types of QuickBits that can be placed onto the electrode tips. By default, electrodes 2-31 should have the medium yellow QuickBits already placed in (they can be taken out). For electrodes 1 (Fp1), 32 (Fp2), and the ground, we should use the flat heads. Underneath the cap, insert the flat heads into each electrode- add a little bit of pressure to do this. Again this is done after the electrodes have already been screwed in.

Clip the electrode bundle to the back of the participant's clothing. Next, hold the cap with the ground facing away from you and your fingers underneath each temporal region. Turn your wrists towards you to flip the cap upside down and inside out. Place the cap on the subject with the ground and frontal electrodes making contact first (make sure there is no hair in the way). When those frontal electrodes make contact with the forehead (above the eyebrows), quickly but carefully pull the cap towards you and down to place the cap fully on the participant's head. Pull on the cap around the sides as needed to make sure it is on properly- meaning that the cap is:

1. not crooked or slanted to the side
2. not too far back or forward
3. ears are in place
4. chin strap is added
5. the electrode nodes (white circles) are strapped to the sides of the cap

Connect the electrode bundle to the slot on top of the amplifier. Place it in the slot closest to the face of the amplifier (where all of the aux ports are). Also insert the ground electrode into the 'GND' slot located on the bottom right.

Connect Electrode Bundle	Connect GND

Open BrainVision Recorder by clicking on the green icon on the computer's desktop. This application will not open if the amplifier is not being powered (by the battery) and if the electrode bundle is not plugged into the amplifier. If there are issues opening this application then disconnect and reconnect the amplifier to the battery.

Open workspace: 'Dry_EEG32.rwksp'

You can check the impedance using the second icon (rectangle) in BrainVision Recorder.

The electrodes should be all red, this is to be expected and will likely not change. The ground may be green or yellow, if so it will make the next part easier. We need to make sure that the Ground electrode, the reference electrode (Pz, 13) and another electrode are less than 500 k0hms. This should be easy to do. You can use your mouse curser to identify what the impedance is for an electrode by placing the cursor over that electrode in this window.

Click on the first icon (the eye)

Make sure the filter setting is on by clicking on the waves icon (three blue squiggly lines next to the 'i' icon). For the 'Dry_EEG32.rwksp' workspace, the filter should be keeping in frequencies between 0.5 and 45 Hz.

Make sure that you are viewing this in the correct scale! There should a 100 microVolts (uV) in the bottom left part of the screen, if this number is not equal to 100 (it is 200 or maybe 50), then click on the icons in red to manipulate the scale.

Communicate with the participant about what you will now start doing. That you will be twisting the electrodes in and moving hair around in the process. Mention that they will feel pressure and that if it becomes uncomfortable that they should let you know!

Now start twisting in all of the electrodes. Most of them should be twisted all the way in. If the participant complains of great discomfort then untwist that electrode. After twisting wiggle the electrode around. You can go up/down left/right or in circles. The goal is to move the hair around to make better contact with the scalp.

After you twist in several electrodes and move the electrodes around in a left/right up/down or squiggly motion, you will see visually that the data quality will start to improve. Eventually there will be a few electrodes that will look considerably noisier than the rest, this is an indication that you are almost done. The next step is to go to these noisy electrodes one by one and either twist them in more or wiggle them around until better connections are made.

To find which electrodes need more work on the cap, you can use the image below as a guide. From the noisy electrodes above, FC1, C3, CP6, CP2, Cz, FC2, F4 and a couple of others need more attention. The image below informs you of where the electrodes on the cap are- keep in mind these will have numbers so use your best judgment to guess where the channel is. Once found, wiggle it around a bit and look visually at the screen, if found the electrode should skyrocket out of view.

Additionally, the electrode names also give you clues about where to look. These names start with a letter (F = frontal, C = central, T = temporal, P = Parietal, O = Occipital) which give you information about the scalp region they are located in. If you see FC then that would mean FrontalCentral. The numbers themselves in the name give in you information about lateralization, with even numbers being on the right side of the scalp and odd on the left. If the name ends with a 'z' then that means it is in the midline of the cap.

TP9 and TP10 are the electrodes behind the ears.

In cases where some electrodes continue to look noisy, this indicates that there is a poor connection between the QuickBit and the participant's scalp. If there is a braid in the way preventing this connection, then move QuickBit around the braid for it to make contact with the scalp. If the QuickBit is not long enough to do so, you can always remove the QuickBit (yellow) and replace it with a red one. Please only do this for electrodes TP9 TP10 or other electrodes that are close to the edge of the cap- do not do this for electrodes that required the full cap to be removed.

Once everything is corrected for, the final data should look like below. If so you can begin the recording. Notice the scale is still the same at 100 microVolts.

dry-EEG is substantially noisier than wet-EEG. For this reason, we must stress to the participant how important it is for there to be little head or body movement during the recordings and no talking. Eye blinks are okay if not too many. They should not have their eyes looking around the room. You can show them how moving around is bad for the EEG by telling them to yawn and move their head around- show them how this changes the EEG to look messy. Tell them that this movement makes it impossible to obtain good readable EEG data so they can understand it is important to stay still and not to talk.

Testers, try to make the environment quiet by not talking amongst yourselves unless it is important to do so.

BrainVision recorder will not show you if line noise is present and contaminating the data. You will have to make sure that nothing is charging near the EEG system. This includes laptops, phones, iPads, etc.

This is the stage where the recordings can begin. We will be switching back and forth between the PsychoPy and EEG Computer.

• Step 13: Record Eyes-Open while watching Inscapes EEG data
• Step 14: Record Eyes-Closed EEG data
• Step 15: Record Inscapes + PsychoPy MMN EEG data
• Step 16: Record CPT EEG data
• Step 17: Remove the EEG cap and unplug it from the amplifier
• Step 18: Clean the dry-EEG Cap
• Step 19: Remove the flat QuickBits and electrodes
• Step 20: Store everything in its proper place
• Step 21: Recharging the battery

The goal is to collect dry-EEG data while the participants are doing different tasks. For this to work, we will need to start the EEG recordings first with a specific filename in a specific location, so we know what that data contains and then quickly start the tasks. These are the following tasks that we will be collecting data from.

Tasks

• 1: 3-minutes Eyes-Open while watching Inscapes
• 2: 3-minutes Eyes-Closed
• 3: Two versions of the MMN while watching Inscapes (for both)
• 4: One version of the CPT

Playing Inscapes

Go to the tablet and click on 'My Files'. Then on the left side click on 'Internal Storage'. Look for the folder 'Documents' and Inscapes will be inside. Open this video using VCL. Before starting the video make sure that the VOLUME IS OFF. We do not want to hear anything from the video. Make sure the tablet is set on its side to make the video as big as possible. Also click on the '...' on the right corner and make sure 'Repeat mode' is pressed (It should be the color orange).

Starting the EEG recording

Before starting the task itself, we need to make sure that the dry-EEG data is being collected for a few seconds. BrainVision Recorder should already be open. What you will want to do is click on the 'Start/ Resume Recording' button, it has a green triangle on it that looks like a play button.

You will then need to choose where this file gets saved and what the filename will be. Each EEG file will be saved in their own folder- this is to make organization easier. Below is a table of how each type of task should be saved and where. You will want to click on Desktop > dryEEG data to get to these saved folders. Each filename will be named by the child's ID followed by the task type. Here are some examples:

• 0003_EO
• 0097_MMN
• 0102_CPT
• 0145_EC

Disclaimer: The pictures below should have the ID number as '0001'

Saving Eyes-Open	Saving Eyes-Closed

Saving MMN	Saving CPT

You can also check how long the recordings are by viewing the Elapsed Time near the bottom. For example, when this timer is around 3 minutes you can stop the recording for the eyes open or eyes closed tasks.

To stop a recording, press the red square button below.

Also, every time you make a new recording, a window will pop up asking to append the data. We will press 'No'.

Starting PsychoPy

Starting PsychoPy is pretty simple. There are two folders saved on the Desktop. One is called 'MMN_MAIN' and the other is called 'CPT_MAIN'. Inside these folders you will find the PyschoPy task, they are the only icons with a circle that has white and black stripes. After opening the task, click on the orange play button at the top.

After this wait a few second and another box will appear. Below type in the ID number followed by _MMN or _CPT, depending on which one is open. Leave the session part tab alone.

Continuing Inspection of the EEG

Just because we got the electrodes to look good in the previous steps does not mean they will remain good for the rest of the session. Visually look at the EEG data to detect any electrodes/channels that could have gotten noisy. When they get noisy, fix them in between tasks!

Tell the child they will be watching a video for 3 minutes. Open 'Inscapes' on the tablet and start the video with NO VOLUME. Then start recording the EEG data with the correct file name and in the correct location (mentioned above). Use the Elapse Time to stop the recording at 3 minutes and 10 seconds.

Investigate and fix noisy electrodes if any.

Tell the child that they will now close their eyes for 3 minutes. Start the EEG recording and say 'No' to appending the data. Use the Elapse Time to stop the recording at 3 minutes and 10 seconds.

Investigate and fix noisy electrodes if any.

Start the EEG recording with the correct file name and location (ex: 001_MMN). Start the 'Inscapes' video on the tablet and make sure the Repeat mode is on. Open the PsychoPy MMN Task and insert the filename for the child (ex: 001_MMN). Do NOT press enter yet.

Tell the child they will be listening to tones for four minutes and afterwards they will be listening to syllables for 7 minutes. They should watch the 'Inscapes' movie while doing this. Put the headphones on the child. Start the MMN by pressing enter in the grey box and wait for 4-5 minutes. Afterwards press enter again to start the syllable version of the task. When the task is fully complete, stop the EEG recording by clicking the red square. Close the PsychoPy MMN task.

Investigate and fix noisy electrodes if any.

You can now remove the tablet since we will no longer need it. Start the EEG recording for the CPT task (ex: 001_CPT). Open the PsychoPy CPT Task and insert the filename for the child (ex: 001_CPT). Do NOT press enter yet.

Tell the child that they will be playing a game where if they see a triangle, a square, a pentagon, a hexagon, a circle or a diamond that they will press the 'spacebar'. After they understand this press 'enter'.

Now tell them that every once and a while a cross will show (like the one on the screen). When they see the cross, they must not touch the 'spacebar'. After they understand tell them they will do a practice version of the game. Press 'enter' to start the practice version. Watch how they perform, if they understand the practice trial, then once it is over tell them the real trial will now begin and press 'enter'. Once the full game is done, stop the EEG recording.

Now that the recordings have been obtained, gently remove the cap from the participant. Start by taking off the chin strap then slowly pull the cap off. Be careful while doing this. There may be cases where the participant's hair may have gotten tangled around an electrode QuickBit, thus pulling on their hair. In these cases, turn the gears slightly to loosen the electrode and remove the hair from the QuickBit with your fingers.

Once the cap is off, unplug the electrode bundle from the amplifier and remove the ground from the amplifier.

Hold the dry-EEG cap inside out, which will expose all of the electrode QuickBits (It might be easier if you have the electrode bundle over your neck just like in Step 4). Take the dry-EEG cleaning spray bottle and spray ~4 times onto a towel. DO NOT SPRAY THE QUICKBITS DIRECTLY. Take this towel and gently wipe over the exposed electrode Quickbits. Aka the electrodes that were making contact with the scalp. Once wiped (should take a minute or so), take the dry side of the towel and wipe them dry.

Also, do the same procedure for the chin strap.

Now that everything is cleaned and disinfected, we can start removing the electrodes from the cap. Start by first removing the three flat QuickBits. They should be immediately stored into their respective bag. Then remove the ground electrode and place it in its bag. Now choose a side (left or right) and start removing each electrode one by one. Do this by twisting the gear counterclockwise. It is important to do one side first or else the electrodes will become extremely tangled with each other.

Put the cap bag in the bag that it came from (its respective size). The dry-EEG electrodes need to go back inside the bubble wrap bag. The dongle and USBc adapters need to be placed in their respective bag. Remove the trigger box and EEG cable. Disconnect the amplifier from the battery and store it. Keep everything nice and organized so we do not lose any equipment by mistake.

After EEG recordings, we must recharge the battery at MRT offices. Forgetting to do so can damage the battery and without it the EEG will not work! As of right now, the battery will be charged overnight in the clinical labs!

Use the LaCie device to save all of the EEG data. Then upload that information into the desktop. Use the 'skip' button when it pops up to save time. You must save the Recording excel file separately- do not skip for that one.