Alpha Power Spectrum Distribution Characteristic Research In EEG Data

Importance: Among the brain electrical signals, alpha wave is one of the most important and famous elements of EEG research, which relates with human's age, memory ability and so on, and under different situation alpha wave in different person will display different appearance cases. Some person have the alpha wave , while some haven't and some person's alpha wave appearance is very strong while others' is weak. So how to abstract alpha wave and certain it's band is a trouble work, so how to determine the appearance situation and band of alpha wave is a very important topic.Objective: This article based on an objective record of EEG data alpha wave power spectrum distribution, through the fellow method, define the different situation of alpha wave and calculate the mainly rang of alpha wave of different person under different state.Methods: Because alpha wave mainly distributes in after forehead, therefore this research is mainly carries on the analysis in view of after forehead four brain electrodes (P₃, P₄, O₁ and O₂). First we carry on the autocorrelation operation to the EEG data; next we do the PSD to the EEG data then according to brain waves show we select a suitable function model for the establishment of EEG data fitting. Since the adoption of relevant sub-studies obtain the alpha wave's main distribution.Result: Through the methods above we can find along with the changes of EEG data's autocorrelation coefficients alpha wave's condition changes simultaneously. While the coefficient in the scope 0.45 to 1, alpha wave's appearance is strong and this moment the accuracy of computed result is correctly; when the coefficient in the rang 0.1 to 0.45, the appearance situation of alpha wave is very unstable, belongs to the condition which alpha wave appears weak, at the same time the computed result's accuracy is unable to guarantee, when the coefficient smaller than 0.1, alpha wave is in a very unusual weak condition.Conclusion: Through the result we can find the autocorrelation coefficient is higher, and alpha wave appearance also on stronger distribution centralism, until reduces along with the autocorrelation coefficient is the zero, alpha wave appearance also changes along with the reduction is weak and loose, gradually to the condition which does not appear. When the autocorrelation coefficient appearance in the rang 0.10 to 0.40, alpha wave's mainly distribution is uncertain; when the autocorrelation coefficient less than 0.10, alpha wave is in a situation of unfound.