Research Of Brain Alertness Improvement Based On The Binaural Beats Acoustic Stimulation

In modern society, with the quicker rhythm of life, longer working hour and larger workload, more and more people are getting in a state of sub-health, such as insomnia, anxiety, attention lapses and lack of alertness. For people who engaged in aerospace, healthcare, transport and other special profession alike, it’s important for them to keep in a high alertness state and have the ability to response to emergency during the long working period. Once their ability of judgment to danger signals goes down due to the decrease of alertness, great casualties and enormous property loss may happen. Thus, the study of enhancing brain alertness has a practical value.The brain wave entrainment effect is that the human brain has a tendency to change its dominant EEG frequency towards the frequency of external stimulus by entraining the brain to synchronize neural activity with external stimulations. Based on this effect, it is of great significance to study the physiological state of brain during physical stimulations. Therefore, this thesis was supposed to change the rhythm of brain though frequency following response induced by binaural beats. Meanwhile, a systemative method of detecting alertness, including operating parameters of task, subjective measurement and characteristic parameters of EEG, was used in this thesis to verify the feasibility of brain alertness enhancing. The main content of this thesis contained the following aspects:1) We have designed a self-adjustment visual-spatial working memory task. Compared with traditional N-back, it added a multi-dimensional workload and set a pass and back mechanism, which could enhance subjects’ positivity and simulate workload in real. Besides the MFI-20 subjective measurement, to be the evaluation index of behavioral parameters, the average reaction time and accuracy were also used to indicate the alertness state.2) A binaural beat acoustic stimulus was designed, which adopted beta frequency to induce brain wave entrainment effect. The stimulation were applied when subject execute the N-back task. Results showed that the effects were different for different subjects. Therefore, we divided subjects into sensitive group and non-sensitive group, and then analyzed the mechanism of this difference by EEG features.3) Features in frequency domain and non-linear characteristics in EEG features were analyzed. Frequency domain characteristic parameters(Relative change of Relative Power and Rate of Power), non-linear characteristic parameters(Lempel-Ziv Complexity) and brain network(Cross Mutual Information and Partial Directed Coherence) were introduced. The results showed that Fp1, Pz, O1 and O2 electrodes were important areas about alertness...