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Titolo: The application of electrical impedance tomography to reduce systematic errors in the EEG inverse problem  a simulation study
Autore: Goncalves, S; de Munck, JC; Heethaar, RM; da Silva, FHL; van Dijk, BW;
 Indirizzi:
 Free Univ Amsterdam Hosp, MEG Ctr KNAW, NL1081 HV Amsterdam, Netherlands Free Univ Amsterdam Hosp Amsterdam Netherlands NL1081 HV m, Netherlands Univ Lisbon, Fac Sci, Inst Biophys & Biomed Engn, P1700 Lisbon, Portugal Univ Lisbon Lisbon Portugal P1700 Biomed Engn, P1700 Lisbon, Portugal Free Univ Amsterdam Hosp, Inst Cardiovasc Res IcaR VU, Lab Clin Phys & Informat, NL1007 MB Amsterdam, Netherlands Free Univ Amsterdam Hosp Amsterdam Netherlands NL1007 MB m, Netherlands Inst Neurobiol, NL1098 SM Amsterdam, Netherlands Inst Neurobiol Amsterdam Netherlands NL1098 SM M Amsterdam, Netherlands
 Titolo Testata:
 PHYSIOLOGICAL MEASUREMENT
fascicolo: 3,
volume: 21,
anno: 2000,
pagine: 379  393
 SICI:
 09673334(200008)21:3<379:TAOEIT>2.0.ZU;2K
 Fonte:
 ISI
 Lingua:
 ENG
 Soggetto:
 SOURCE LOCALIZATION; MEG;
 Keywords:
 electrical impedance tomography; electrical conductivities; 3layer sphere head model; EEG inverse problem; dipole position error; dipole strength error; systematic errors;
 Tipo documento:
 Article
 Natura:
 Periodico
 Settore Disciplinare:
 Clinical Medicine
 Life Sciences
 Citazioni:
 16
 Recensione:
 Indirizzi per estratti:
 Indirizzo: Goncalves, S Free Univ Amsterdam Hosp, MEG Ctr KNAW, Recept C,Boelelaan 1117, NL1081 HV Amsterdam, Netherlands Free Univ Amsterdam Hosp Recept C,Boelelaan 1117 Amsterdam Netherlands NL1081 HV



 Citazione:
 S. Goncalves et al., "The application of electrical impedance tomography to reduce systematic errors in the EEG inverse problem  a simulation study", PHYSL MEAS, 21(3), 2000, pp. 379393
Abstract
In this paper we propose a new method, using the principles of electrical impedance tomography (EIT), to correct for the systematic errors in the inverse problem (IP) of electroencephalography (EEG) that arise from the wrongspecification of the electrical conductivities of the head compartments. By injecting known currents into pairs of electrodes and measuring the resulting potential differences recorded from the other electrodes, the equivalent conductivities of brain (sigma(3)), skull (sigma(2)) and scalp (sigma(1)) can be estimated. Since the geometry of the head is assumed to be known, the electrical conductivities remain as the only unknown parameters to be estimated. These conductivities can then be used in the inverse problem of EEG. The simulations performed in this study, using a threelayer sphere to model the head, prove the feasibility of the method, theoretically. Even inthe presence of simulated noise with a value of signaltonoise ratio (SNR) equal to 10, estimations of the electrical conductivities within 5% of the true values were obtained. Simulations showed the existence of a strong relation between errors in the skull thickness and the EIT estimated conductivities. If the skull thickness is wrongly specified, for example overestimated by a factor of two, the conductivity determined by EIT is also overestimated by a factor of two. Simulations showed that this compensation effectalso works in the inverse problem of EEG. Application of the proposed method reduces systematic errors in the dipole localization, up to an amount of1 cm. However it proved to be ineffective to decrease the dipole strength error.
ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 08/04/20 alle ore 11:06:52