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Recording of electrical brain activity in a magnetic resonance environment: Distorting effects of the static magnetic field
Author(s) -
Müri René M.,
Felblinger Jacques,
Rösier Kai M.,
Jung Bruno,
Hess Christian W.,
Boesch Chris
Publication year - 1998
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.1910390105
Subject(s) - electroencephalography , artifact (error) , amplitude , signal (programming language) , subtraction , magnetic field , nuclear magnetic resonance , evoked potential , magnetic resonance imaging , physics , computer science , psychology , mathematics , neuroscience , artificial intelligence , optics , medicine , arithmetic , quantum mechanics , radiology , programming language
The technical limitations of electroencephalography (EEG) and flashed visually‐evoked potentials (VEP) recordings in the static magnetic field of the MR system were systematically studied. A main artifact occurring in the magnetic field was found to be correlated with the heart cycle and had amplitudes in the range of EEG and VEP signals. For VEP recordings, a substantial reduction of this effect was achieved by subtraction of the averaged artifact from the averaged composed signal (VEP and artifact) resulting in the VEP signal alone. However, for continuous EEG recordings, there is no such solution, since the observed effect is not sufficiently constant in amplitude, and the standard deviation of the amplitude of the effect is often larger than the EEG amplitude.