title: Assessment of mental workload: A new electrophysiological method based on intra-block averaging of ERP amplitudes.
abstract: The present study contributes to the current debate about electrophysiological measurements of mental workload. Specifically, the allocation of attentional resources during different complexity levels of tasks and its changes over time are of great interest. Therefore, we investigated mental workload using tasks varying in difficulty during an auditory oddball target paradigm. For data analysis, we applied a novel method to compute event-related potentials (ERPs) by intra-block epoch averaging of P2, P3a and P3b amplitude components for the infrequent target stimuli. We obtained eight consecutive blocks of 5 epochs each, which allowed us to develop an electrophysiological parameter to measure mental workload. In both the easy and the more constraining tasks, the amplitude of P2 decreased beginning with the second block of the sequence. In contrast, the amplitudes of P3a and P3b components linearly decreased following the repetition of the target in the more constraining task, but not in the easy task. Statistical analysis revealed intra-block differences on amplitudes of ERPs of interest between the easy and the more constraining tasks, confirming this method as a measure to assess mental workload. Since a subject is his own control, the present method represents an electrophysiological parameter for individual measurement of mental workload and may therefore be applicable in clinical routine.
authors.affiliation: Unit of Psychiatric Neuroscience and Psychotherapy, Department of Medicine, Faculty of Science, University of Fribourg, Chemin du Musée 5, 1700 Fribourg, Switzerland.
authors.forename: Sibylle K
authors.initials: SK
authors.lastname: Horat
authors.affiliation: Department of Rehabilitation and Geriatrics, University Hospitals of Geneva, 2 chemin du Petit-Bel-Air, Chêne-Bourg, Geneva 1225, Switzerland.
authors.forename: François R
authors.initials: FR
authors.lastname: Herrmann
authors.affiliation: Mental Health Network Fribourg (RFSM), Sector of Psychiatry and Psychotherapy for Adults, L'Hôpital 140, Case postale 90, 1633 Marsens, Switzerland.
authors.forename: Grégoire
authors.initials: G
authors.lastname: Favre
authors.affiliation: HELIOS Privatkliniken GmbH - Wuppertal-Universität/Barmen, Heusnerstrasse 40, 42283 Wuppertal, Germany; Department of Neurosurgery, Universität Kliniken der Stadt Köln gGmbH, Krankenhaus Merheim, 51109 Köln, Germany.
authors.forename: Jorge
authors.initials: J
authors.lastname: Terzis
authors.affiliation: HELIOS Privatkliniken GmbH - Wuppertal-Universität/Barmen, Heusnerstrasse 40, 42283 Wuppertal, Germany; Department of Neurosurgery, Universität Kliniken der Stadt Köln gGmbH, Krankenhaus Merheim, 51109 Köln, Germany.
authors.forename: Damien
authors.initials: D
authors.lastname: Debatisse
authors.affiliation: Unit of Psychiatric Neuroscience and Psychotherapy, Department of Medicine, Faculty of Science, University of Fribourg, Chemin du Musée 5, 1700 Fribourg, Switzerland.
authors.forename: Marco C G
authors.initials: MCG
authors.lastname: Merlo
authors.affiliation: Unit of Psychiatric Neuroscience and Psychotherapy, Department of Medicine, Faculty of Science, University of Fribourg, Chemin du Musée 5, 1700 Fribourg, Switzerland; Mental Health Network Fribourg (RFSM), Sector of Psychiatry and Psychotherapy for Adults, L'Hôpital 140, Case postale 90, 1633 Marsens, Switzerland. Electronic address: pascal.missonnier@unifr.ch.
authors.forename: Pascal
authors.initials: P
authors.lastname: Missonnier
mesh_terms: D000328:Adult; D001288:Attention / Q000502:physiology*; D001307:Auditory Perception / Q000502:physiology*; D002540:Cerebral Cortex / Q000502:physiology*; D004569:Electroencephalography / Q000379:methods*; D005072:Evoked Potentials, Auditory; D005260:Female; D006801:Humans; D008297:Male; D009483:Neuropsychological Tests; D012815:Signal Processing, Computer-Assisted; D055815:Young Adult
keywords: Attention; Event-related potential; Mental workload; Oddball paradigm