Scaling behavior in β-wave amplitude modulation and its relationship to alertness

Abstract.

 We performed an experimental study of β waves occurring in human electroencephalographic signals obtained from six healthy subjects that were monitored during the performance of a task requiring attention to auditory signals. We use wavelet analysis to study whether the fluctuations in the modulation of the β-wave amplitude related to an indirect measurement of alertness. We found that these fluctuations exhibit a power-law behavior. When the level of alertness dropped, the associated exponent was found to increase, reflecting the fact that long-range correlations grow rapidly within the system. We also studied the fluctuations of amplitude modulation for α and θ waves, for which we did not find a power-law behavior.