Beta/alpha power ratio and alpha asymmetry characterization of EEG signals due to musical tone stimulation

• Main Author: Noscal, Maria Michaela M.
• Format: text
• Language: English
• Published: Animo Repository 2016
• Subjects: Electroencephalography; Alpha rhythm; Beta rhythm; Engineering
• Online Access: https://animorepository.dlsu.edu.ph/etd_bachelors/2864
• Institution: De La Salle University

During communication or when listening to the different parts of a musical piece, the brain emits minute electrical signals called electroencephalogram (EEG). Through EEG signals, the complexity of the brain can be explored and may be incorporated in several researches. In this study, the reaction of the brain when stimulated by a musical tones was investigated. This study used C, F and G notes found in the fourth octave of a standard grand piano keyboard in order to provoke a reaction in the brain. The beta/alpha power ratio and alpha asymmetry of the obtained EEG signal was investigated. There were four segments considered in the EEG signal: baseline, S-baseline, C, F and G segments. The brain regions considered were frontal, temporal, parietal, and occipital regions. The left and right hemisphere were also considered. The beta/alpha power ratio was based on the logarithmic value of the ratio of the beta and alpha power spectrum vectors. Results show that in all regions of interest, the baseline has the most negative value. However, the S-baseline (the resting state instance after every tone) was found to be generally greater than C and G but less than F in the left and right hemispheres of the brain. The alpha asymmetry was obtained using the difference score method (DSM). Results show that the temporal, parietal and occipital nodes are left asymmetric while frontal nodes are right asymmetric. The frequency response of the audio stimulus and the EEG signal was also observed in terms of amplitude, power and phase. In general, it was found that there is a significant difference between the frequency response of the brain. This shows that the brain waves do not oscillate in the same manner as its stimulus.