[Changes of EEG frequency-fluctuation characteristics during visual workloads].

OBJECTIVE

To observe the changes of alpha-band frequency-fluctuation characteristics of EEG under visual task.

METHOD

Nineteen healthy right-handed male volunteers served as subjects, aged 24-32. EEG were recorded during rest (eyes-closed and eyes-open) and visual task, then analyzed using EEG frequency-fluctuation analysis system.

RESULT

From eyes-closed to eyes-open, then to visual task state, the probability distribution characteristics of alpha-band frequency-fluctuation were significantly changed. The probability of 9 Hz and 10 Hz dominance decreased significantly, while the probability of 8 Hz and 11-13 Hz dominance increased significantly. The single component occupying absolute dominance was gradually transformed into the competition between these various components, and the lower frequency component in the front brain-areas gradually occupied dominance; meanwhile, the dominant fluctuation entropy increase significantly, the dominant fluctuation energy decreased significantly, and these processes showed obviously the brain-area related characteristics.

CONCLUSION

These changes of alpha-band frequency-fluctuation characteristics reflect the further enhancement of brain activities in the areas related to visual task. This method may be helpful in the study of visual workloads.