title: EEG-based workload estimation across affective contexts.
abstract: Workload estimation from electroencephalographic signals (EEG) offers a highly sensitive tool to adapt the human-computer interaction to the user state. To create systems that reliably work in the complexity of the real world, a robustness against contextual changes (e.g., mood), has to be achieved. To study the resilience of state-of-the-art EEG-based workload classification against stress we devise a novel experimental protocol, in which we manipulated the affective context (stressful/non-stressful) while the participant solved a task with two workload levels. We recorded self-ratings, behavior, and physiology from 24 participants to validate the protocol. We test the capability of different, subject-specific workload classifiers using either frequency-domain, time-domain, or both feature varieties to generalize across contexts. We show that the classifiers are able to transfer between affective contexts, though performance suffers independent of the used feature domain. However, cross-context training is a simple and powerful remedy allowing the extraction of features in all studied feature varieties that are more resilient to task-unrelated variations in signal characteristics. Especially for frequency-domain features, across-context training is leading to a performance comparable to within-context training and testing. We discuss the significance of the result for neurophysiology-based workload detection in particular and for the construction of reliable passive brain-computer interfaces in general.
authors: Institut National de Recherche en Informatique et en Automatique, Bordeaux Sud-Ouest Talence, France.
authors: Christian
authors: C
authors: Mühl
authors: Institut National de Recherche en Informatique et en Automatique, Bordeaux Sud-Ouest Talence, France ; Laboratoire Handicap et Système Nerveux, University of Bordeaux Bordeaux, France.
authors: Camille
authors: C
authors: Jeunet
authors: Institut National de Recherche en Informatique et en Automatique, Bordeaux Sud-Ouest Talence, France ; Laboratoire Bordelais de Recherche en Informatique (LaBRI) Talence, France.
authors: Fabien
authors: F
authors: Lotte
keywords: brain–computer interface; classification; electroencephalography; passive brain computer interface; stress; workload