A Systematic Review of Physiological Measures of Mental Workload

Abstract

Mental workload (MWL) can affect human performance and is considered critical in the design and evaluation of complex human-machine systems. While numerous physiological measures are used to assess MWL, there appears no consensus on their validity as effective agents of MWL. This study was conducted to provide a comprehensive understanding of the use of physiological measures of MWL and to synthesize empirical evidence on the validity of the measures to discriminate changes in MWL. A systematical literature search was conducted with four electronic databases for empirical studies measuring MWL with physiological measures. Ninety-one studies were included for analysis. We identified 78 physiological measures, which were distributed in cardiovascular, eye movement, electroencephalogram (EEG), respiration, electromyogram (EMG) and skin categories. Cardiovascular, eye movement and EEG measures were the most widely used across varied research domains, with 76%, 66%, and 71% of times reported a significant association with MWL, respectively. While most physiological measures were found to be able to discriminate changes in MWL, they were not universally valid in all task scenarios. The use of physiological measures and their validity for MWL assessment also varied across different research domains. Our study offers insights into the understanding and selection of appropriate physiological measures for MWL assessment in varied human-machine systems.

Review of Eye Tracking Metrics Involved in Emotional and Cognitive Processes

“…These include measurements through fixations, eye movements, blinks and pupil size. Blink rate, pupil diameter, blink duration and fixation duration seem to be the most frequently used eyerelated measures [141].…”

Can Reactivity of Heart Rate Variability Be a Potential Biomarker and Monitoring Tool to Promote Healthy Aging? A Systematic Review With Meta-Analyses

“…In particular, considering the cardiac vagal reactivity to cognitive or physical exercises is important to understand the individual's adaptability to a specific situation (Laborde et al, 2018 ). In fact, recent systematic reviews have concluded, that phasic HRV responses are sensitive to task demands (e.g., difficulty, complexity, and duration) related to cognitive and mental effort in older adults with and without cognitive impairment (Castaldo et al, 2015 ; Ranchet et al, 2017 ; Kim et al, 2018 ; Charles and Nixon, 2019 ; Hughes et al, 2019 ; Tao et al, 2019 ). Furthermore, measures of phasic HRV responses are suitable to distinguish between different intensities and durations of physical exercises (e.g., cardiorespiratory; Dong, 2016 ; Michael et al, 2017 ; Gronwald and Hoos, 2020 ).…”

Assessment of Implicit and Explicit Measures of Mental Workload in Working Situations: Implications for Industry 4.0

“…Recent literature reviews have reported a series of implicit measures of MWL that are affected by variations in the imposed level of mental workload [12,22], such as the heart rate (HR), which increases with higher task demands [23] and multitasking conditions [24]. Another example is the skin conductance (SC, or electrodermal activity; EDA) which has been shown to increase in different situations such as complex driving environments [21] and the presence of secondary tasks [18,25].…”