Research On The Neurofeedback Technology Based On Phase Decoding Of Alpha Wave And External-regulation

Neurofeedback is an important brain-computer interaction technique,which uses visual or auditory stimulation,normally generated based on users' ongoing electroencephalography(EEG),as feedback to help users regulate their brain electrical activity.Neurofeedback has been widely used to enhance perceptual/cognitive functions and rehabilitate mental illness.However,the efficacy of neurofeedback remains controversial because a significant proportion of users are unable to properly regulate their brain activity and benefit from neurofeedback.In fact,the effect of neurofeedback greatly depends on the ability of self-regulation and degree of training,so its performance and applicability are limited.To address the neurofeedback inefficacy problem,the present study is aimed to design and implement a new neurofeedback system that can more effectively and consistently regulate users' brain activities than the conventional way of training users to voluntarily regulate brain activities.The new neurofeedback system delivers external visual stimuli continuously at a specific alpha phase,which is real-time decoded from ongoing alpha wave,to regulate the alpha wave.Specifically,we first used experimental results to validate the modulation effect of alpha phase at the delivery time of visual stimuli on the dynamic behavior of alpha wave.This observation inspires us to continuously deliver visual stimuli at a specific alpha phase to modulate the alpha wave to expected dynamic behaviors,which is the basis of the proposed new externally-regulated neurofeedback(ER-NF)protocol.A new hardware and software system of the ER-NF system was designed and implemented.Experimental results show that the proposed training-free ER-NF system can achieve consistent(effective in almost all sessions for almost all users),flexible(either increasing or decreasing peak alpha frequency and alpha power),and immediate(taking or losing effect immediately after stimulation is on or off)modulation effects on alpha wave.Therefore,the ER-NF system holds great potential to be able to more reliably and flexibly modulate cognition and behavior,and ultimately provide an alternative and effective means for enhancement of cognitive functions and rehabilitation of mental disorders.