StaglinCenter:EEG:Cap

Preparing the Electrolyte Solution

1. In the prep room, grab an empty plastic bucket and fill it with warm water to the 2 quart line.

2. Mix in 1 scoop of the potassium chloride and 1 spoonful of shampoo.

• Each has its own measuring spoon which you should find in the potassium chloride box and next to the shampoo. The spoons are also conveniently titled "potassium chloride" and "shampoo" on their handles. You can use the "shampoo" spoon to stir the solution until the ingredients have fully dissolved.

Fitting the Right Cap

1. Measure the circumference of the largest part of your subject's head in centimeters (usually sits right above the eyes).

2. Match this measurement to the range displayed on the plugs of one of the caps.

Measuring and Marking the Vertex

To find the point where the reference electrode (REF) should sit, you'll take 2 perpendicular measurements with the red pencil in hand:

1. Measure from behind the top of one ear to the same point behind the other ear (like where a headband would sit).

• Draw a short perpendicular line at the midpoint of this distance.

2. For the perpendicular nasion/inion measurement, ask the subject to hold the starting end of the measuring tape between his or her eyes and then draw the tape back to just below the bump at the back of the head.

• Draw a short perpendicular line at the midpoint of this distance.

3. Referencing your 2 marks, draw a cross at the intersection to find the vertex.

Soaking the Net

1. Wrap the towel around the plug of the previously determined cap. This connection must always remain DRY!

2. Turn the net inside out with the sponges facing out, make sure all clasps are fully loosened, and immerse the net in the electrolyte solution so that all sensors are fully submerged.

• It is easiest to place the wrapped plug on a chair and then have the bucket of solution on the floor or in the sink to ensure the plug doesn't come near water.

3. Let the net soak for 5-10 minutes.

• If the net is soaked for too long, it may take up too much solution which can cause bridging between sensors so be mindful of the time!

Applying the Net

1. Have the subject sit in a chair facing you. Place the bucket with the soaking net on the floor in front of them and ask them to hold the wrapped plug in their lap. Place a towel over his or her shoulders to catch drips.

2. Turn the net back the right way (sponges in) and gently shake excess electrolyte solution from the net.

3. Place both hand inside the net with your fingers spread out to stretch the net.

• The elastics holding the net together are very delicate so careful not to overstretch the net!

4. Instruct your subject to close his or her eyes.

5. Begin to bring the stretched net straight down over your subject's head. Align the center front electrode between their eyes and then slightly rotate your hands back to stretch the net back and down the back of the head.

6. Tighten the sides and then center clasps.

• At this point you may allow your subject to open his or her eyes and dry any drips as needed.

7.To align the cap over the ear holes correctly and to match REF to the vertex, plant all five fingers in the net and then move as needed, wiggling the net a bit to allow the sensors to find their place through the hair.

• Once again, the net is very delicate! Moving with the whole hand, finger planted in various positions will more gently and efficiently shift/move the cap for you.

Plug the net into the amp by first positioning the plug in the amp and then turning the knob from up to down. The plug will draw itself into the correct position.