Analysis of chaotic dynamics in EEG and its application to assessment of mental workload

An attempt was made to evaluate mental workload using chaotic analysis of EEG, EEG signals registered from Fz and Cz during a mental task (mental addition task) were recorded and analyzed using chaotic measures such as attractor plot, fractal dimension and Lyapunov exponent, which are used to clarify chaotic dynamics, to investigate whether mental workload could be assessed using these measures. The largest Lyapunov exponent for all experimental conditions took positive values, which indicated chaotic dynamics In the EEG signals. However, the authors could not evaluate mental workload using the largest Lyapunov exponent or attractor plot. The fractal dimension, on the other hand, tended to increase with the work level. The authors concluded that the fractal dimension can be used to evaluate the mental state, especially a mental workload induced by mental task loading