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dc.contributor.authorMahadeva Iyer, Parameswaran
dc.contributor.authorMohr, Kieran
dc.contributor.authorNasseroleslami, Bahman
dc.contributor.authorHardiman, Orla
dc.contributor.authorLalor, Edmund C.
dc.contributor.authorDukic, Stefan
dc.date.accessioned2023-10-23T13:38:01Z
dc.date.available2023-10-23T13:38:01Z
dc.date.created2017en
dc.date.issued2017
dc.date.submitted2017en
dc.identifier.citationParameswaran Mahadeva Iyer, Kieran Mohr, Bahman Nasseroleslami, Orla Hardiman, Edmund C. Lalor, Stefan Dukic, 'Estimation of coherence using the median is robust against EEG artefacts', Annu Int Conf IEEE Eng Med Biol Soc, 2017 Jul;2017:3949-3952en
dc.identifier.otherY
dc.identifier.urihttp://hdl.handle.net/2262/104058
dc.description.abstractCoherence is a mathematical measure of correlation in the frequency domain, commonly used to quantify the oscillatory synchrony of bio-signals such as the electroencephalogram (EEG). In biomedical applications, such as assessment of functional connectivity, reliable estimation of coherence is of paramount importance for studying the function of complex brain networks, as well as their disruption in neurological disorders. A major challenge for robust estimation of coherence measures is the presence of artefacts. Here, we propose an alternative method for finding coherence by estimating auto- and cross-spectral densities based on the median or trimmed-mean values across trials, rather than the mean. The variance of the average cortico-cortical coherence measures, i.e., the inter-individual variability, was taken as a measure of robustness and tested on resting-state recordings from 34 healthy individuals, both without screening, as well as after screening by a statistical thresholding artefact rejection. The variability of average coherence in individual channels and frequency bands decreased by using the median-based estimation of coherence. Averaged across all channels and frequency bands, the variability of coherence estimates based on median was significantly lower than mean-based estimates for both unscreened data (F = 9.28, p = 0.003, 1-β0.05 = 0.98) and screened data (F = 6.58, p = 0.01, 1-β0.05 = 0.91). Moreover, the variability for median-based estimates was almost identical for unscreened and screened data (F = 0.004, p = 0.95), suggesting that coherence based on median without artefact rejection might be sufficient for robust estimation of coherence.en
dc.format.extent3949en
dc.format.extent3952en
dc.language.isoenen
dc.rightsYen
dc.subjectSpectral Coherenceen
dc.subjectEEGen
dc.subjectSignal Processingen
dc.subjectNon-parametric Statisticsen
dc.titleEstimation of coherence using the median is robust against EEG artefactsen
dc.title.alternative2017 39th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC)en
dc.title.alternativeAnnual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC)en
dc.typeConference Paperen
dc.type.supercollectionscholarly_publicationsen
dc.type.supercollectionrefereed_publicationsen
dc.identifier.peoplefinderurlhttp://people.tcd.ie/nasserob
dc.identifier.peoplefinderurlhttp://people.tcd.ie/hardimao
dc.identifier.rssinternalid181727
dc.identifier.doihttp://dx.doi.org/10.1109/EMBC.2017.8037720
dc.rights.ecaccessrightsopenAccess
dc.identifier.orcid_id0000-0002-2227-2176
dc.contributor.sponsorHealth Research Boarden
dc.contributor.sponsorGrantNumberHRA-POR-2013-246en


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