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dc.contributor.authorLópez-Larraz, Eduardo
dc.contributor.authorFigueiredo, Thiago C.
dc.contributor.authorInsausti-Delgado, Ainhoa
dc.contributor.authorZiemann, Ulf
dc.contributor.authorBirbaumer, Niels
dc.contributor.authorRamos-Murguialday, Ander
dc.date.accessioned2018-10-23T09:26:50Z
dc.date.available2018-10-23T09:26:50Z
dc.date.issued2018
dc.identifier.citationLópez-Larraz, Eduardo, Thiago C. Figueiredo, Ainhoa Insausti-Delgado, Ulf Ziemann, Niels Birbaumer, and Ander Ramos-Murguialday. “Event-Related Desynchronization During Movement Attempt and Execution in Severely Paralyzed Stroke Patients: An Artifact Removal Relevance Analysis.” NeuroImage: Clinical 20 (2018): 972–986. doi:10.1016/j.nicl.2018.09.035.en
dc.identifier.issn2213-1582en
dc.identifier.urihttp://hdl.handle.net/11556/631
dc.description.abstractThe electroencephalogram (EEG) constitutes a relevant tool to study neural dynamics and to develop brain-machine interfaces (BMI) for rehabilitation of patients with paralysis due to stroke. However, the EEG is easily contaminated by artifacts of physiological origin, which can pollute the measured cortical activity and bias the interpretations of such data. This is especially relevant when recording EEG of stroke patients while they try to move their paretic limbs, since they generate more artifacts due to compensatory activity. In this paper, we study how physiological artifacts (i.e., eye movements, motion artifacts, muscle artifacts and compensatory movements with the other limb) can affect EEG activity of stroke patients. Data from 31 severely paralyzed stroke patients performing/attempting grasping movements with their healthy/paralyzed hand were analyzed offline. We estimated the cortical activation as the event-related desynchronization (ERD) of sensorimotor rhythms and used it to detect the movements with a pseudo-online simulated BMI. Automated state-of-the-art methods (linear regression to remove ocular contaminations and statistical thresholding to reject the other types of artifacts) were used to minimize the influence of artifacts. The effect of artifact reduction was quantified in terms of ERD and BMI performance. The results reveal a significant contamination affecting the EEG, being involuntary muscle activity the main source of artifacts. Artifact reduction helped extracting the oscillatory signatures of motor tasks, isolating relevant information from noise and revealing a more prominent ERD activity. Lower BMI performances were obtained when artifacts were eliminated from the training datasets. This suggests that artifacts produce an optimistic bias that improves theoretical accuracy but may result in a poor link between task-related oscillatory activity and BMI peripheral feedback. With a clinically relevant dataset of stroke patients, we evidence the need of appropriate methodologies to remove artifacts from EEG datasets to obtain accurate estimations of the motor brain activity.en
dc.description.sponsorshipThis study was funded by the fortüne-Program of the University of Tübingen (2422-0-1 and 2452-0-0), the Bundesministerium für Bildung und Forschung BMBF MOTORBIC (FKZ 13GW0053) and AMORSA (FKZ 16SV7754), the Deutsche Forschungsgemeinschaft (DFG), the Basque Government Science Program (EXOTEK: KK 2016/00083). The work of A. Insausti-Delgado was supported by the Basque Government's scholarship for predoctoral students.en
dc.language.isoengen
dc.publisherElsevier Inc.en
dc.rightsAttribution-NonCommercial-NoDerivatives 4.0 International*
dc.rights.urihttp://creativecommons.org/licenses/by-nc-nd/4.0/*
dc.titleEvent-related desynchronization during movement attempt and execution in severely paralyzed stroke patients: An artifact removal relevance analysisen
dc.typearticleen
dc.identifier.doi10.1016/j.nicl.2018.09.035en
dc.rights.accessRightsopenAccessen
dc.subject.keywordsElectroencephalogram (EEG)en
dc.subject.keywordsArtifactsen
dc.subject.keywordsMotor cortical activityen
dc.subject.keywordsBrain-machine interfaces (BMI)en
dc.subject.keywordsStrokeen
dc.journal.titleNeuroImage: Clinicalen
dc.page.final986en
dc.page.initial972en
dc.volume.number20en


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