Comparison of sensitivity of mental load assessment indexes

: Objective. To compare the sensitivities of indexes used in the assessment of mental load. Method. Twenty five indexes belonging to primary task performance, additional task performance, subjective rate and psychophysiological measure were recorded during performance of 11 different difficult tasks. Result. It showed that tracking error (ER), reaction time (RT), correct rate (CR), category scale (CS), multistage evaluation scale (MES), multi-dimensional scale (MDS), latency of P3 (LAT), inter beat interval (IBI), inter respiration interval (IRI) and blink rate (BR) were significantly different among the various tasks. CS, MES and MDS were more sensitive to the total load; ER, LAT, IBI and IRI were more sensitive to the load of primary task, while RT and CR to that of additional task and BR to the visual load. Conclusion. It demonstrated that the sensitivities of the various indexes are different and the information are limited. Multi-indexes may be preferred for mental load assessment.