Thom Lab

Introduction

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In order to achieve precise and trustworthy data, proper setup and calibration of the NIRScout is key. This process involves:

• Conducting a phantom test prior to participant data collection

• Selecting the desired optode montage for the cap and fitting the cap onto the participant

• Calibration of the fNIRS system 

• Collecting the data from the participant

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​​Preparation of the NIRScout (prior to participant arrival)

At least 30 minutes prior to the arrival of the participant, switch on the NIRScout system (switch on the backside of the chassis) so that the red "Power" light is on. (Note: The green "Status" light may be on or flashing, but this does not mean the system is on.)

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Perform a Phantom Test

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A calibration test is used to ensure that all optodes are functioning properly. While a phantom test is not necessary to do before every participant's data is collected, it should be completed at least once before an entire study is conducted. 

Place optodes in chronological order, alternating source and detector (i.e. Source 1, Detector 1,

Source 2, Detector 2, etc.). There should not be a source next to another source or a detector next

to another detector. ​

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Place the Phantom setup inside of a dark sleeve (black laptop case) and close it as much as possible,

careful to not damage the cords. Turn the light in the lab room off and close the door as much as

possible. (NOTE: Don't completely shut the door; it will lock)

                      Open the NIRStar application on the desktop. (If you turn the system off and power it

                      back on again while NIRStar is running, you must shut down NIRStar and reopen it again

                      otherwise tests will not run properly.) Select "Configure Hardware" in the top left

                      corner of the screen. Select "Hardware Specification" at top. Under the "Study Type"

                      dropdown, select "Static Phantom". (NOTE: Available sources should be set to "8"

                      and Available detector cards should be "2") Select "OK".​

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Select the "CALIBRATE" button on the right hand side of the screen. The test is done when the loading screen disappears and "Calibration finished" is displayed in the System Status History window. If all boxes on the Signal Quality window are green (ignoring any empty grey spaces), the calibration was successful and you may move on to fitting the optodes onto a cap. If any squares are yellow, red, or white, select the "DETAILS" button above the calibrate button to decipher where the problem is.​

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​​​​Placing the NIRS Cap and Optodes​

There are various montages you can choose to use depending on where you are looking to measure on the participant's head. For the purposes of this explanation, the "Prefrontal_8x8" montage will be used. This montage setup is printed on the wall in the lab room. 

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Once the participant arrives, welcome the participant and ask if they would have a seat in the EEG collection room. Begin by explaining the procedure, what you will be doing, and what the participant will be doing during the testing as well as the time requirement.

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Measure their head with a tape measure from their nasion (area in between the eyebrows) to their inion (the projection of the occipital bone on the back of the skull) to determine which cap size is appropriate. Place the optodes in the correct montage setup on the cap with the wires facing the back of the cap. Be very careful with the optodes and wires, as they will easily scratch or crack, and the wires may easily be damaged by pinching. ​​

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Carefully place the cap onto the participant's head ensuring that their ears align with the ear holes and the chin strap is snug but not tight. Move as much hair out of the way as possible. After the cap is on, an over-cap may be necessary if the participant cannot sit in the dark to perform the study. 

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Watch this video for a demonstration on how to apply the NIRS cap:

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