Artefacting reliability in QEEG topographic maps.
OBJECTIVE
To quantify the extent of disagreement among expert artefactors, to compare their results with a 'minimalist' approach where only gross artefacts were removed, and to relate the result to frequency and to cranial location.


METHODS
Raw QEEG records for 12 subjects were artefacted by 6-expert, and one 'minimalist', artefactor. Standard errors (SEs) of measurement were computed for each of 20 1.2 Hz frequency bins in each of 20 electrode positions.


RESULTS
SEs declined with frequency. SEs associated with the 'minimalist' were comparable to those of the experts. The high SEs in delta were confined to the frontal and frontotemporal regions. SEs were small and uniform over the cranium for frequencies greater than 5.2 Hz.


CONCLUSIONS
Artefactor unreliability is a serious problem in the delta band because of disagreement on eye movement artefacts. The success of the 'minimalist' suggests that automated methodologies may be a feasible alternative to the use of expert technicians.


CONCLUSIONS
A novel statistical procedure proves helpful in elucidating the sources of artefactor error and points to possible remedies.
Lawson
J Stuart
JS
Department of Psychiatry, Queen's University, Kingston, Ont., Canada K7L 3N6. lawsonj@post.queensu.ca
Galin
Howard
H
Adams
Susan J
SJ
Brunet
Donald G
DG
Criollo
Margarita
M
MacCrimmon
Duncan J
DJ
D000328:Adult; D016477:Artifacts; D001931:Brain Mapping / Q000379:methods*; D002540:Cerebral Cortex / Q000502:physiology; D016001:Confidence Intervals; D004569:Electroencephalography / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male