CookiesWe use cookies to enhance your experience and the functionality of our website. By continuing to browse, you are agreeing to our use of cookies. Learn More

CookiesWe use cookies on our website. By continuing to browse, you are agreeing to our use of cookies. Learn More

New Inner Balance™ Coherence Plus Sensor and App: Includes Free Lifetime Access to the New HeartMath® App Learn More

Research Library

Measuring Mental Workload with Low‑Cost and Wearable Sensors: Insights into the Accuracy, Obtrusiveness, and Research Usability of Three Instruments

    • Published: 2017
    • Julia C. Lo, Emdzad Sehic, Prorail, and Sebastiaan A. Meijer
    • KTH Royal Institute of Technology. Journal of Cognitive Engineering and Decision Making, December 2017, Volume 11, Number 4, pp. 323–336. DOI: 10.1177/1555343417716040.
    • Download the complete paper, click here.


The affordability of wearable psychophysiological sensors has led to opportunities to measure the mental workload of operators in complex sociotechnical systems in ways that are more objective and less obtrusive. This study primarily focuses on the sensors themselves by investigating low-cost and wearable sensors in terms of their accuracy, obtrusiveness, and usability for research purposes. Two sensors were assessed on their accuracy as tools to measure mental workload through heart rate variability (HRV): the E3 from Empatica and the emWave Pro from HeartMath. The BioPatch from Zephyr Technology, which is an U.S. Food and Drug Administration-approved device, was used as a gold standard to compare the data obtained from the other 2 devices regarding their accuracy on HRV. Linear dependencies for 6 of 10 HRV parameters were found between the emWave and BioPatch data and for 1 of 10 for the E3 sensor. In terms of research usability, both the E3 and the BioPatch had difficulty acquiring either sufficiently high data recording confidence values or normal distributions. However, the BioPatch output files do not require postprocessing, which reduces costs and effort in the analysis stage. None of the sensors was perceived as obtrusive by the participants.