Spatial localization of EEG electrodes

Koessler, Laurent; Maillard, Louis; Benhadid, Adnane; Vignal, Jean–Pierre; Braun, Marc; Vespignani, Hervé

doi:10.1016/j.neucli.2007.03.002

Cited by 76 publications

(71 citation statements)

References 14 publications

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“…Assuming the exact placement of the base electrodes the accuracy of the proposed method is assessed to be within the range of 5.5 mm. This is very close to the other methods [7,8] which claim comparative accuracy of up to 5 mm. To increase the accuracy it would be justified to mark more than five electrodes.…”

Section: Introductionsupporting

confidence: 84%

Invisible Base Electrode Coordinates Approximation for Simultaneous SPECT and EEG Data Visualization

Kowalczyk

Goszczyńska

Zalewska

et al. 2014

Measurement Science Review

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This work was performed as part of a larger research concerning the feasibility of improving the localization of epileptic foci, as compared to the standard SPECT examination, by applying the technique of EEG mapping. The presented study extends our previous work on the development of a method for superposition of SPECT images and EEG 3D maps when these two examinations are performed simultaneously. Due to the lack of anatomical data in SPECT images it is a much more difficult task than in the case of MRI/EEG study where electrodes are visible in morphological images. Using the appropriate dose of radioisotope we mark five base electrodes to make them visible in the SPECT image and then approximate the coordinates of the remaining electrodes using properties of the 10-20 electrode placement system and the proposed nine-ellipses model. This allows computing a sequence of 3D EEG maps spanning on all electrodes. It happens, however, that not all five base electrodes can be reliably identified in SPECT data. The aim of the current study was to develop a method for determining the coordinates of base electrode(s) missing in the SPECT image. The algorithm for coordinates approximation has been developed and was tested on data collected for three subjects with all visible electrodes. To increase the accuracy of the approximation we used head surface models. Freely available model from Oostenveld research based on data from SPM package and our own model based on data from our EEG/SPECT studies were used. For data collected in four cases with one electrode not visible we compared the invisible base electrode coordinates approximation for Oostenveld and our models. The results vary depending on the missing electrode placement, but application of the realistic head model significantly increases the accuracy of the approximation.

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Section: Introductionsupporting

confidence: 84%

Invisible Base Electrode Coordinates Approximation for Simultaneous SPECT and EEG Data Visualization

Kowalczyk

Goszczyńska

Zalewska

et al. 2014

Measurement Science Review

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“…Reference and ground were taken at FCz (midline, central frontal) and AFz (midline, anterior frontal), respectively. Positions of the 96 electrodes were obtained as follows: the three fiducials (nasion, left ear, right ear) and six well distributed electrodes (Fp1, Fp2, P3, P4, Cz, Oz) were measured manually with calipers (Koessler et al, 2007). Those measures were then used to obtain the positions of all electrodes after computation of the affine transformation that best fitted the canonical EEG cap provided in SPM8 onto the head of each subject (Wellcome Trust Centre for Neuroimaging, http://www.fil.ion.ucl.ac.uk/spm/).…”

Section: Eeg Acquisitionmentioning

confidence: 99%

Dynamic Causal Modeling of Spatiotemporal Integration of Phonological and Semantic Processes: An Electroencephalographic Study

Yvert

Perrone‐Bertolotti²,

Baciu³

et al. 2012

J. Neurosci.

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Integration of phonological and lexicosemantic processes is essential for visual word recognition. Here we used dynamic causal modeling of event-related potentials, combined with group source reconstruction, to estimate how those processes translate into context-dependent modulation of effective connectivity within the temporal-frontal language network. Fifteen healthy human subjects performed a phoneme detection task in pseudo-words and a semantic categorization task in words. Cortical current densities revealed the sequential activation of temporal regions, from the occipital-temporal junction toward the anterior temporal lobe, before reaching the inferior frontal gyrus. A difference of activation between phonology and semantics was identified in the anterior temporal lobe within the 240 -300 ms peristimulus time window. Dynamic causal modeling indicated this increase of activation of the anterior temporal lobe in the semantic condition as a consequence of an increaseofforwardconnectivityfromtheposteriorinferiortemporallobetotheanteriortemporallobe.Inaddition,fastactivationoftheinferior frontal region, which allowed a feedback control of frontal regions on the superior temporal and posterior inferior temporal cortices, was found to be likely. Our results precisely describe spatiotemporal network mechanisms occurring during integration of phonological and semantic processes. In particular, they support the hypothesis of multiple pathways within the temporal lobe for language processing, where frontal regions would exert a top-down control on temporal regions in the recruitment of the anterior temporal lobe for semantic processing.

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“…(i) Manual methods, 8,14 (ii) Electromagnetic radiofrequency (RF) digitizer usage, 28,33 (iii) Magnetic Resonance Imaging (MRI)-assisted approaches, 10,25,40,44 (iv) Ultrasonic wave transmission and reflection methods, 29,30 (v) Photogrammetric measurement principles. 5,38 The photogrammetric method seems to be a fast, remote, patient specific, repeatable procedure, and it is less prone to human error.…”

Section: Introductionmentioning

confidence: 99%

Single Camera Photogrammetry System for EEG Electrode Identification and Localization

Baysal

Şengül

2010

Ann Biomed Eng

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In this study, photogrammetric coordinate measurement and color-based identification of EEG electrode positions on the human head are simultaneously implemented. A rotating, 2MP digital camera about 20 cm above the subject's head is used and the images are acquired at predefined stop points separated azimuthally at equal angular displacements. In order to realize full automation, the electrodes have been labeled by colored circular markers and an electrode recognition algorithm has been developed. The proposed method has been tested by using a plastic head phantom carrying 25 electrode markers. Electrode locations have been determined while incorporating three different methods: (i) the proposed photogrammetric method, (ii) conventional 3D radiofrequency (RF) digitizer, and (iii) coordinate measurement machine having about 6.5 mum accuracy. It is found that the proposed system automatically identifies electrodes and localizes them with a maximum error of 0.77 mm. It is suggested that this method may be used in EEG source localization applications in the human brain.

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Spatial localization of EEG electrodes

Cited by 76 publications

References 14 publications

Invisible Base Electrode Coordinates Approximation for Simultaneous SPECT and EEG Data Visualization

Invisible Base Electrode Coordinates Approximation for Simultaneous SPECT and EEG Data Visualization

Dynamic Causal Modeling of Spatiotemporal Integration of Phonological and Semantic Processes: An Electroencephalographic Study

Single Camera Photogrammetry System for EEG Electrode Identification and Localization

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