Mental Workloads Can Be Objectively Quantified in Real-time Using VOR (Vestibulo-Ocular Reflex)

Abstract This present study offers a new method to quantify mental workloads (MWL) utilizing vestibule-ocular reflex (VOR). The VOR method makes use of the relation between a person's VOR responses and his/her mental demands; Human VOR responses can be accurately predicted in a dynamical equation that is a function of the person's head movements, unless the person is engaging in a higher cognitive activity. In this present study, the coherence between the predicted VOR and the observed VOR was as high as 0.92 when there was no additional mental demands. However, the manipulation of MWL in five different tasks (i.e. the n-back task) revealed that the VOR coherences declined with the heavier MWL demands. This shows that MWL can be objectively quantified by measuring the gap between observed VOR responses and the mathematical-model-predicting VOR. This may be applicable in the future to quantifying a vehicle driver's MWL in real-time.