EOG correction: a new aligned-artifact average solution

Objective: In the field of EOG correction, discrepancies have been found be tween the propagation rates for different types and frequencies of eye move ment. However, Croft and Barry demonstrated that these differences can be e xplained by the affect of EOG magnitude on the correction procedure (Croft, R.J. and Barry, R.J. EOG correction: a new perspective. Electroenceph. cli n. Neurophysiol., 1998, 107: 387-394). This study utilized a new 'aligned-a rtifact average' technique (AAA) to examine whether propagation is constant across eye movement types and frequencies, and tested the AAA as an EOG co rrection tool. Methods: Two experiments manipulated interference levels in real data sets to determine if interference affected propagation coefficients (Bs). The th ird tested real data for the effect of forward propagation of eye movement related neural potentials on Bs, and the fourth utilized computer simulatio ns to assess the effectiveness of the new AAA correction procedure. Results: Interference was found to inflate B at low EOG amplitude, and its removal removed B variation and inflation. The forward propagation of eye m ovement related neural potentials had very little effect on B. The AAA proc edure produced near perfect corrections of the simulated data, superior to a comparison method. Conclusions: EOG propagation is constant across eye movement types and freq uencies, and thus only one correction coefficient should be calculated and applied to data. The AAA method provides a more accurate correction and mak es possible, for the first time, the adequate correction of posterior sites . (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.