Detection of spatial abnormalities in the EEG by spherical harmonic expansion

The application of a spherical harmonic expansion to the spatial aspect of the electroencephalogram (EEG) is explored. Using the method of singular-value decomposition to estimate the coefficients of a truncated expansion, a spatially smoothed EEG is reconstructed. This smoothed EEG is then used to extract a localized feature. The application of this method to the general problem of the detection of localized abnormalities and artifacts is discussed.<
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