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EEG Recorded from the Ear: Characterizing the Ear-EEG Method

Highlights: Auditory middle and late latency responses can be recorded reliably from ear-EEG. For sources close to the ear, ear-EEG has the same signal-to-noise-ratio as scalp. Ear-EEG is an excellent match for power spectrum-based analysis. A method for measuring electroencephalograms (EEG) from th...

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Autores principales: Mikkelsen, Kaare B., Kappel, Simon L., Mandic, Danilo P., Kidmose, Preben
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Frontiers Media S.A. 2015
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4649040/
https://www.ncbi.nlm.nih.gov/pubmed/26635514
http://dx.doi.org/10.3389/fnins.2015.00438
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author Mikkelsen, Kaare B.
Kappel, Simon L.
Mandic, Danilo P.
Kidmose, Preben
author_facet Mikkelsen, Kaare B.
Kappel, Simon L.
Mandic, Danilo P.
Kidmose, Preben
author_sort Mikkelsen, Kaare B.
collection PubMed
description Highlights: Auditory middle and late latency responses can be recorded reliably from ear-EEG. For sources close to the ear, ear-EEG has the same signal-to-noise-ratio as scalp. Ear-EEG is an excellent match for power spectrum-based analysis. A method for measuring electroencephalograms (EEG) from the outer ear, so-called ear-EEG, has recently been proposed. The method could potentially enable robust recording of EEG in natural environments. The objective of this study was to substantiate the ear-EEG method by using a larger population of subjects and several paradigms. For rigor, we considered simultaneous scalp and ear-EEG recordings with common reference. More precisely, 32 conventional scalp electrodes and 12 ear electrodes allowed a thorough comparison between conventional and ear electrodes, testing several different placements of references. The paradigms probed auditory onset response, mismatch negativity, auditory steady-state response and alpha power attenuation. By comparing event related potential (ERP) waveforms from the mismatch response paradigm, the signal measured from the ear electrodes was found to reflect the same cortical activity as that from nearby scalp electrodes. It was also found that referencing the ear-EEG electrodes to another within-ear electrode affects the time-domain recorded waveform (relative to scalp recordings), but not the timing of individual components. It was furthermore found that auditory steady-state responses and alpha-band modulation were measured reliably with the ear-EEG modality. Finally, our findings showed that the auditory mismatch response was difficult to monitor with the ear-EEG. We conclude that ear-EEG yields similar performance as conventional EEG for spectrogram-based analysis, similar timing of ERP components, and equal signal strength for sources close to the ear. Ear-EEG can reliably measure activity from regions of the cortex which are located close to the ears, especially in paradigms employing frequency-domain analyses.
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spelling pubmed-46490402015-12-03 EEG Recorded from the Ear: Characterizing the Ear-EEG Method Mikkelsen, Kaare B. Kappel, Simon L. Mandic, Danilo P. Kidmose, Preben Front Neurosci Neuroscience Highlights: Auditory middle and late latency responses can be recorded reliably from ear-EEG. For sources close to the ear, ear-EEG has the same signal-to-noise-ratio as scalp. Ear-EEG is an excellent match for power spectrum-based analysis. A method for measuring electroencephalograms (EEG) from the outer ear, so-called ear-EEG, has recently been proposed. The method could potentially enable robust recording of EEG in natural environments. The objective of this study was to substantiate the ear-EEG method by using a larger population of subjects and several paradigms. For rigor, we considered simultaneous scalp and ear-EEG recordings with common reference. More precisely, 32 conventional scalp electrodes and 12 ear electrodes allowed a thorough comparison between conventional and ear electrodes, testing several different placements of references. The paradigms probed auditory onset response, mismatch negativity, auditory steady-state response and alpha power attenuation. By comparing event related potential (ERP) waveforms from the mismatch response paradigm, the signal measured from the ear electrodes was found to reflect the same cortical activity as that from nearby scalp electrodes. It was also found that referencing the ear-EEG electrodes to another within-ear electrode affects the time-domain recorded waveform (relative to scalp recordings), but not the timing of individual components. It was furthermore found that auditory steady-state responses and alpha-band modulation were measured reliably with the ear-EEG modality. Finally, our findings showed that the auditory mismatch response was difficult to monitor with the ear-EEG. We conclude that ear-EEG yields similar performance as conventional EEG for spectrogram-based analysis, similar timing of ERP components, and equal signal strength for sources close to the ear. Ear-EEG can reliably measure activity from regions of the cortex which are located close to the ears, especially in paradigms employing frequency-domain analyses. Frontiers Media S.A. 2015-11-18 /pmc/articles/PMC4649040/ /pubmed/26635514 http://dx.doi.org/10.3389/fnins.2015.00438 Text en Copyright © 2015 Mikkelsen, Kappel, Mandic and Kidmose. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
spellingShingle Neuroscience
Mikkelsen, Kaare B.
Kappel, Simon L.
Mandic, Danilo P.
Kidmose, Preben
EEG Recorded from the Ear: Characterizing the Ear-EEG Method
title EEG Recorded from the Ear: Characterizing the Ear-EEG Method
title_full EEG Recorded from the Ear: Characterizing the Ear-EEG Method
title_fullStr EEG Recorded from the Ear: Characterizing the Ear-EEG Method
title_full_unstemmed EEG Recorded from the Ear: Characterizing the Ear-EEG Method
title_short EEG Recorded from the Ear: Characterizing the Ear-EEG Method
title_sort eeg recorded from the ear: characterizing the ear-eeg method
topic Neuroscience
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4649040/
https://www.ncbi.nlm.nih.gov/pubmed/26635514
http://dx.doi.org/10.3389/fnins.2015.00438
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