Electroencephalogram EEG Procedure

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Electroencephalogram(EEG) Procedure
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Step 1

• Subject Preparation
• Ensure the subject washes their hair with shampoo
  before having the EEG. No other hair products
  should be used (e.g., conditioner, gel). A
  plastic/cloth hair tie can be used to put long
  hair in a low pony tail.
• Have the subject read and sign a consent form.
• Ask the subject to remove all metal jewelry, hair
  ties, glasses etc.

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Step 2

• Setting Up for the EEG
• Set out chest belt, earlobe electrodes, EEG
  abrasive skin prepping gel, Signa-gel electrode
  gel, alcohol wipes, cotton buds, gauze, E6
  disposable sponge discs, Ten20 conductive EEG
  paste.

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Step 2 continued

• Attach sponge discs to electrodes FP1 and FP2.
• Primary researcher must scrub hands with hospital
  standard soap and put on gloves.
• Fill syringe with electrode gel. To do this,
  insert the syringe into the gel container and
  retract the plunger gently. Gel should fill the
  syringe.
• When syringe is filled with electrode gel, attach
  a flat-tipped needle. Leave the protective lid of
  the needle in place and put the syringe aside
  until ready to use.

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Step 3

• Setting Up The Computer
• Turn on computer Green button (power supply)
• Press Enter to select A MS-Dos
• Press Enter to select Cee-graph Brain Atlas
  from the Biologic System
• Select ltbrain atlasgt
• Select ltcollection/analysisgt
• Select ltCollectiongt
• Select ltCalgt
• Select ltstart calibrationgt
• If the calibration values are within 10 of 100
  (i.e., between 99 101), Click ltAcceptgt
• Write down all calibration values

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Step 4

• Using the special marker tape, measure the
  subjects head circumference to determine the cap
  size to be used.
• Blue area blue cap (Large)
• Red area red cap (Medium)
• Yellow area yellow cap (Small - usually used
  for children)

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Step 5

• Use a tape measure to measure the distance from
  the inion (knob at first vertebrae just below
  occipital arch) to the nasion (area at top of
  nose just below the brow bone).

inion
nasion
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Step 6

• Use the 10-20 system (i.e., 2X10 4x20) to
  work out the measurement from the nasion to the
  location of electrode FPZ on the forehead. This
  distance is 10 of the measurement found at Step
  4 (e.g., 37.5cm 3.75cm)
• Mark this point with a pen.

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Step 7

• Ask the subject to fasten the chest belt, button
  side up. The subject may need some help doing
  this, so ask before assisting.
• Ensure the subject is comfortable.
• Using an alcohol swab, wipe the subjects
  forehead and ear lobes. Repeat this cleaning
  process using prepping gel on gauze. Ensure the
  areas are thoroughly cleaned.

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Step 8

• Place skull cap on head and ensure the electrode
  FPZ is lined up over the dot mark made at Step 7.
• Ensure that the sponge discs at FP1 and FP2 are
  secured to the subjects forehead, then while the
  subject holds the cap securely at these points,
  stretch it over the head.
• Ensure that none of the electrode wires of the
  skull cap are sitting under any electrodes.

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Step 9

• Clean the scalp by inserting a plastic pipette
  with prepping gel into each electrode on the cap
  and wiggle and rotate pipette to clean
  thoroughly. The end of a wooden cotton bud may be
  used but this can be painful if care is not
  taken.The electrode FPZ can be skipped as it is
  really only for positioning purposes.

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Step 10

• Use a cotton bud with prepping gel and twirl it
  inside the cup of the earlobe electrodes to
  remove any silver build up.
• Fill left earlobe electrode cup (white) with EEG
  paste and clip to left earlobe. The cup goes on
  the front of the lobe.
• Ask the subject to connect the left skull cap
  strap to the chest belt.
• Fill right earlobe electrode cup (blue) with EEG
  paste and clip to right earlobe.
• Ask the subject to connect the left skull cap
  strap to the chest belt.

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Step 11
Wire from Cap electrodes

• Attach electrode wires from the skull cap and
  earlobes to the machine.
• If necessary, tape wires to the subjects
  shoulder to avoid swing.

Earlobe electrode wires
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Step 12

• Insert needle of syringe gently into each cap
  electrode so that it touches the subjects scalp.
  The subject should feel the needle. Be careful
  not to jab their scalp.
• Pull the needle slowly upward whilst pushing the
  syringe plunger to fill the electrode with gel.
• Use a slight rotation/wiggle technique to ensure
  gel connects well with both the skin and
  electrode. The pipette can be used for this task
  as well. The subject should experience only a
  slight discomfort, not pain.
• Repeat this for all electrodes except FPZ.

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Inserting the Gel
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Step 13

• Test the Impedances
• On the computer, select ltchannel impedancegt
• Impedance levels should be low, ideally under 3.
  Check any electrodes that are high. They may need
  to be cleaned again and/or some more gel added.
  Rotate/wiggle pipette in electrode to get a good
  connection as in Step 13.
• Electrode FZ is the ground reading and show be
  low (i.e., below 5).
• The two earlobe electrodes are identified as the
  reference.

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Step 14

• Gathering Data
• After validating the connections, select ltStartgt
• In order to display partial readings and
  graphical presentation of brain waves (e.g., the
  first 10 readings), right-click and select
  ltdisplaygt. Then select ltchannelsgt. Select lt10gt.
  Select ltstart discard all datagt and then select
  ltraisegt.

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Step 14 continued

• Instruct the subject to undertake the task being
  investigated. If the EEG is for demonstration
  purposes only, ask the subject to perform several
  tasks such as blink or, close eyes and imagine an
  object.
• Write down all the impedance readings for the
  connected electrodes.

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Obtaining Data
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Step 15

• Finishing off the EEG
• When finished collecting brain wave readings,
  check the calibration again and note the values
  (see Step 3).
• Save data and then select ltQuitgt to exit
  software. Turn the computer off.
• Disconnect the electrodes from the machine.
• Ask the subject to undo the skull cap straps and
  remove the chest belt.

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Step 15 continued

• Gently detach any sponge discs and remove the
  skull cap.
• Wipe the subjects earlobes and forehead to
  remove any gel and the positioning mark for
  electrode FPZ.
• Thank the subject for their patience and time.

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Step 16

• Cleaning Up
• Dispose of used needle in sharps waste
  container.
• Discard all used swabs, paper towel, gauze, and
  cotton buds.

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Step 16 continued
Wearing safety glasses and gloves, use cotton
buds to remove as much gel as possible from each
electrode. Run under cold water and continue to
clean with cotton buds several times. Make sure
the electrode plug does not get wet.
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Step 16 continued

• In hot water use a new cotton bud to wipe out
  each electrode again. Twirl the cotton bud to
  ensure the electrodes are free of silver build
  up. Rinse and repeat several times to thoroughly
  clean.
• Mix warm water and hibitane and allow the cap to
  soak for 20 30 minutes.
• Hang up to dry. Do not squeeze as this will
  damage the electrodes.

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Step 16 continued

• Use a cotton bud to remove paste from earlobe
  electrode cups. Twirl to remove any silver build
  up. Rinse and repeat several times.
• Hang up to dry.
• Discard gloves.
• Pack all equipment away neatly.

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• Instructor
• Dr. Malcolm Mills
• Written, designed demonstrated by
• A. Lamont, L. Leung, A. Pfeffer, R. Tan, S.
  Kunaselan, M. Kimura. C. Lau, S. Loxley, C.
  Smith, Y. Fujita, Bec, Jenny, K. Lee.