In vivo measurement of the brain and skull resistivities using an EIT-based method and the combined analysis of SEF/SEP data.
IEEE Trans Biomed Eng
; 50(9): 1124-8, 2003 Sep.
Article
em En
| MEDLINE
| ID: mdl-12943281
ABSTRACT
Results of "in vivo" measurements of the skull and brain resistivities are presented for six subjects. Results are obtained using two different methods, based on spherical head models. The first method uses the principles of electrical impedance tomography (EIT) to estimate the equivalent electrical resistivities of brain (rhobrain), skull (rhoskull) and skin (rhoskin) according to. The second one estimates the same parameters through a combined analysis of the evoked somatosensory cortical response, recorded simultaneously using magnetoencephalography (MEG) and electroencephalography (EEG). The EIT results, obtained with the same relative skull thickness (0.05) for all subjects, show a wide variation of the ratio rhoskull/rhobrain among subjects (average = 72, SD = 48%). However, the rhoskull/rhobrain ratios of the individual subjects are well reproduced by combined analysis of somatosensory evoked fields (SEF) and somatosensory evoked potentials (SEP). These preliminary results suggest that the rhoskull/rhobrain variations over subjects cannot be disregarded in the EEG inverse problem (IP) when a spherical model is used. The agreement between EIT and SEF/SEP points to the fact that whatever the source of variability, the proposed EIT-based method
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Fenômenos Fisiológicos da Pele
/
Crânio
/
Encéfalo
/
Tomografia
/
Impedância Elétrica
/
Eletroencefalografia
/
Potenciais Somatossensoriais Evocados
Tipo de estudo:
Diagnostic_studies
/
Evaluation_studies
/
Prognostic_studies
Idioma:
En
Revista:
IEEE Trans Biomed Eng
Ano de publicação:
2003
Tipo de documento:
Article
País de afiliação:
Holanda