Artifact robust estimation of cognitive load by measuring cerebral blood flow

Cognitive load reflects the strength of efforts and difficulties in learning. It is known that cognitive load can be estimated by measuring the cerebral blood flow around prefrontal area. This study aims utilizing for the remote skill education service (e-learning) where trainee´s psychological status is difficult to be guessed from his/her trainees via an internet communication. In previous study, artifact robust estimation method of cognitive load was proposed. First, in order to investigate relation between activation level of cerebral blood flow and types of the learning tasks without body motion, cerebral blood flow on performing some mathematical tasks was measured and analyzed. As a result, it was found that the subtraction task evoked brain activity. Next, other cerebral blood flow during performing the subtraction task on walking was measured by cooperating with two participants to obtain the data disturbed with an artifact caused by body motion. Comparing the two cases of cerebral blood flow data, a robust method to estimate cognitive load was found by the spectral and correlation analysis. It was significantly confirmed that the presented method could distinguish the trainee´s cognitive load even when he/she moved the body involving the skill learning. In this study, an effectivity of proposal method was verified by increasing participants. The same experiment was performed by cooperating with five participants, and obtained data was analyzed with proposal method to estimate cognitive load. In conclusion, it was confirmed that proposal method using spectral and correlation analysis was effective significantly to estimate cognitive load against body motion.