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.

A Review of Psychophysiological Measures to Assess Cognitive States in Real-World Driving

“…Recent work has also examined how neural indices (as measured by both P3 ERP components) are associated with subjective workload (as measured by NASA-TLX) and how this covariation is influenced by cognitive effort (Yakobi, 2018). Novel techniques (such as intra-block averaging of ERP amplitudes; Horat et al, 2016) can enable robust electrophysiological measurement of cognitive demands over time. Thus, ERPs are an attractive measure for studying cognitive states and performance in driving contexts.…”

Differences in Social Decision-Making between Proposers and Responders during the Ultimatum Game: An EEG Study

“…It has been established that the attention level is related to mental effort (Miller et al, 2011), and we previously reported that a reduced allocation of attention results in a reduced P2 amplitude (Horat et al, 2016). Interestingly, in the UG the different number of options (nine in the proposer condition vs. two in the responder) does not require the same level of mental effort.…”

“…The P2 is usually observed maximally over frontal regions, and is modulated during cognitive tasks involving workload and attentional processes (Horat et al, 2016). Globally, the P2 is related to higher-order processes that involve the comparison of the eliciting event of the ERP with internal representation or expectation (Luck and Hillyard, 1994; Evans and Federmeier, 2007; Fiori et al, 2013).…”

Neurophysiological Signature of Memory Performance during the DRM Task

“…The present observations should also be interpreted in conjunction with findings regarding the P2 modulation associated with workload changes. It was documented that the morphology of P2 is modulated by mental workload in visual [43] and additive paradigms [21]. According to this theoretical point of view, the lower P2 amplitude in bad performers indicates low workload capacities in this group.…”

“…This component has been described to be maximal at fronto-central electrode sites. Secondly, the DRM also involved selective attention related to discrimination processes [18][19][20] and working memory processes [21], reflected by the positive component, the P2, peaking around 200 ms after stimulus onset. This component is localized in the fronto-centrol-parietal electrode sites.…”