Application of chaotic dynamics in EEG to assessment of mental workload

In this paper, an attempt was made to evaluate mental workload using chaoti c analysis of EEG. EEG signals registered from Fz and Cz during a mental ta sk (mental addition) were recorded and analyzed using attractor plots, frac tal dimensions, and Lyapunov exponents in order to clarify chaotic dynamics and to investigate whether mental workload can be assessed using these cha otic measures. The largest Lyapunov exponent for all experimental condition s took positive values, which indicated chaotic dynamics in the EEG signals . However, we could not evaluate mental workload using the largest Lyapunov exponent or attractor plot. The fractal dimension, on the other hand, tend ed to increase with the work level. We concluded that the fractal dimension might be used to evaluate a mental state, especially a mental workload ind uced by mental task loading.