Dominant frequency band patterns analysis of a singlechannel Electroencephalogram (EEG) in multisensory motor imagery tasks

This study analyses how the brain responds during motor imagery (MI) in a multisensory setting using a single- channel electroencephalogram (EEG). This is a part of early research toward brain-computer interface (BCI) development. The MI tasks involved four types of hand movements, each representing movement instructions to the right (RI), left (LI), forward (FI) and backward (BI). EEG signals were collected from eight healthy participants with ages ranging from 20 to 22 years (mean age= 20.94 ± 0.873) using the EMOTIV Insight 2.0 headset. For this study, only the AF3 channel positioned over the prefrontal cortex was selected for further analysis as a single-channel EEG configuration. The MI tasks are commonly associated with changes in brain activity within the alpha (8-12 Hz) and beta (13-30 Hz) bands, particularly over sensorimotor areas. The results show the variation in dominant frequency band for each stimulus, providing valuable insights into the variation brain activity in the multisensory setting. The power spectral density (PSD) demonstrates the dominant frequency for the signal of AF3 is mainly within the alpha and beta bands as commonly applied in MI-BCI. However, theta (4-8 Hz) activity emerged as the dominant frequency band in specific tasks and stimulus such as RI and BI with the stimulus of the sound of rain. This could mean that MI requires additional efforts in certain circumstances. The presence of the theta band for MI is beneficial to ensure that relevant information is not excluded for further analysis.