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  • Z J Koles
  • 1991
A method is described which seems to be effective for extracting the abnormal components from the clinical EEG. The approach involves the use of a set a spatial patterns which are common to recorded and 'normal' EEGs and which can account for maximally different proportions of the combined variances in both EEGs. These spatial factors are used to decompose(More)
A method is described which can be used to extract common spatial patterns underlying the EEGs from two human populations. These spatial patterns account, in the least-squares sense, maximally for the variance in the EEGs from one population and minimally for the variance in the other population and therefore would seem to be optimal for quantitatively(More)
Imaging studies and quantitative EEG have often, but not consistently, implicated the right hemisphere and the left prefrontal cortex in depression. To help clarify this picture, a spatial filter shown to be effective for enhancing differences between EEG populations was combined with an electrical tomographic approach called low-resolution electromagnetic(More)
Eleven consecutive patients with primary obsessive-compulsive syndrome were studied neuropsychologically and the power spectral EEG characteristic of ten of these patients unmedicated, at rest, and during cognitive tasks were analyzed. The finding of predominantly left frontal dysfunction in the obsessional syndrome is discussed in the light of(More)
The EEG characteristics of 63 depressive psychotics, 75 manics and 53 schizophrenic patients, consecutive admissions satisfying research criteria, are presented. Statistical comparisons between the psychotic groups and of each psychotic group against 60 normal controls (all dextral) were undertaken for power, coherence and phase characteristics in the 8-13(More)
  • Z J Koles
  • 1998
The concepts underlying the quantitative localization of the sources of the EEG inside the brain are reviewed along with the current and emerging approaches to the problem. The concepts mentioned include monopolar and dipolar source models and head models ranging from the spherical to the more realistic based on boundary and finite elements. The forward and(More)
A method, based on principal components for localizing the sources of the background EEG, is presented which overcomes the previous limitations of this approach. The spatiotemporal source model of the EEG is assumed to apply, and the method involves attempting to fit the spatial aspects of this general model with an optimal rotation of a subset of the(More)
OBJECTIVES The spatio-temporal decomposition (STD) approach was used to localize the sources of simulated electroencephalograms (EEGs) to gain experience with the approach for analyzing real data. METHODS The STD approach used is similar to the multiple signal classification method (MUSIC) in that it requires the signal subspace containing the sources of(More)
The spatial patterns underlying differences in the background EEGs of schizophrenic, manic and depressed patients and a group of normal controls has been examined during the eyes open and eyes closed resting conditions and during 3 cognitive tasks. The method of principal-component analysis was used to extract spatial patterns which are common to the EEGs(More)
EEGs were recorded from 75 normal, young, female subjects during psychometrically matched verbal (WF) and spatial (DL) cognitive tasks to elicit the differences in the electrical source distribution inside the brain. Recordings were obtained using 43 EEG and 3 guard electrodes then visually edited and spatially filtered to remove extracerebral artifacts.(More)