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Basic EEG Laboratory Methods Basic EEG
Laboratory Methods
Don M. Tucker
Electrical Geodesic, Inc. Basic EEG Laboratory Methods
Laboratory Safety
Electrical Safety: Isolation Criterion
Isolated Common and Ground
Scalp Abrasion:
SPR Recommendations
Center for Disease Control Criteria
Electrical Recording with Differential Amplifiers
Reference and Active Electrodes
Bipolar and Monopolar Montages
The Zero Surface Integral
Bias of the Average Reference
The PARE Effect
Spatial Sampling of Head Electrical Fields
Normal ERP
Stroke EEG Pathology ¥ Laboratory Safety
Electrical Safety: Isolation Criterion
Isolated Common and Ground
Scalp Abrasion:
SPR Recommendations
Center for Disease Control Criteria Laboratory Safety
Subject Isolation Laboratory Safety
Subject Isolation Laboratory Safety
Isolated Common vs Ground
- finger in socket criterion Laboratory Safety
Scalp Abrasion & Lesions
Picton, T. W., et al. (2000). Guidelines for using human event-related
potentials to study cognition: Recording standards and publication criteria.
Psychophysiology, 37, 127-152.
Recommend lancing the skin to eliminate skin potentials
Use sterlie lances, but not sterile electrodes. Laboratory Safety
Scalp Abrasion & Lesions
Abrasion, or other breaks in the skin, can allow seepage of blood products
carrying such pathogens as hepatitis B virus and the human immunodeficiency
virus that causes AIDS.
Thus electrodes require high- level disinfection before reuse on non-intact
skin. In addition, technicians should wear gloves during skin preparation and
should abrade the skin no more than necessary, using only sterile, preferably
non-sharp materials.
The highest risk is that associated with items that enter sterile tissue, such as
subdermal electrodes and the needles and lancets sometimes used in skin
preparation. Such items must be sterile at the time of use and must be handled
with extreme caution.
L. E. Putnam, R. Johnson, Jr. and W. T. Roth. (1992). Guidelines for reducing
the risk of disease transmission in the psychophysiology laboratory. SPR Ad
Hoc Committee on the Prevention of Disease Transmission.
Psychophysiology, 29(2), 127-41. Laboratory Safety
Center for Disease Control Criteria:
Contact with Blood or Tissue:
Sterilization
Contact with Mucous Membranes: High-level Disinfection
Contact with Intact Skin:
Clean Basic EEG Laboratory Methods
Electrical Recording with Differential Amplifiers
Reference and Active Electrodes
Bipolar and Monopolar Montages
The Zero Surface Integral
Bias of the Average Reference
The PARE Effect Interpreting Signals from
Differential Amplifiers Interpreting Signals from
Differential Amplifiers Referenced Recordings Referenced Recordings Referenced Recordings: The Zero Surface Integral Geodesic Sensor Net Geodesic Sensor Net No Tears Brain Waves 128 channels Junghofer, M., Elbert, T., Tucker, D. M., & Braun, C. (1999). The polar average
reference effect: a bias in estimating the head surface integral in EEG recording.
Clin Neurophysiol, 110(6), 1149-1155.
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Multiple
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Single
Random
Source
Top
Bottom
a)
b)
0
1
Scalp Potential [µV]
-1
Polar average reference effect / Junghöfer et al. 1998 / Figure 7
50

40
30 20
10
CBF Level
cc/100g/min
Protein Synthesis
Glutamate Release
Infarct
K+, Ca++
ATP,
PCr
EEG Changes Observed
Supression
Slow-Wave Increase Stroke Patient 80-year-old Female Right posterior temporal and occipital lesion Sx include left hemiplegia and mild left sided neglect.
Later developed aphasia EEG collected one day after development of aphasia Information loss with sparse EEG arrays Stroke characterized with dwi MRI: Source
Localization Error with Sparse Array Information loss with sparse EEG arrays
Luu, P., Tucker, D. M., Englander, R., Lockfeld, A., Lutsep, H., & Oken, B.
(submitted). Localizing Stroke-Related EEG Changes: Assessing the Effects of Spatial
Under-Sampling. Clinical Neurophysiology.