[Application of brain state related EEG complexity measure in mental workload evaluation]

Objective. The Application of Cs to mental workload evaluation was investigated. Method. EEG of 47 male (aged 23-33) were recorded during rest or doing mental arithmetic, and changes of Cs with relation to mental arithmetic load were analyzed and compared by means of Cs analysis method. Result. Cs distribution was laterally symmetry, higher in temporal and lower in occiput. The changes of Cs over some brain areas were outstanding and stable while doing mental arithmetic: type A, 38 subjects (81%), Cs under mental arithmetic were significantly higher than Cs under rest except over prefrontal, and the most outstanding areas were post-temporal and left parieto-occipital regions; type B, 9 subjects (19%), Cs over post-temporal and parieto-occipital under rest is higher than type A, and Cs under mental arithmetic descend significantly (the most outstanding areas were right central and mid-temporal, then left frontal-central and pre-temporal). Moreover there were some possible relationship among Cs, mental arithmetic score and subjective evaluation of mental workload. Conclusion. There exists high correlation between Cs and mental arithmetic activity, and Cs could well reflect brain function state. It provide a new method and a possible way for objective evaluation of mental workload and studies of brain cognitive activities.