Research On The Improvement Of Weak Acoustic Signal Detection For Auditory Brain-computer Interaction Systems

Hearing is one of the important ways for human to acquire information.However,due to our limited perception ability,weak acoustic signals near the auditory threshold are difficult to be perceived.Brain-computer interaction(BCI)system can transform the activity of central nervous into artificial output,which can enhance,complement or improve human cognitive and sensory functions.Thus it's promising to improve the recognition ability of weak acoustic signals by integrating the brain's auditory information processing ability with the computer's information processing ability.In addition,transcranial direct current stimulation(tDCS)can enhance the cognitive efficiency of the brain and thus promote the ability of auditory recognition.This study designed an auditory detection task where subjects were required to detect the weak target sounds near the auditory threshold.Sixteen healthy subjects were recruited in the experiment.As a result,the average response accuracy across all subjects was 55.72%,and the average response time was 580.87 ms.We found that the weak auditory stimulus could induce a smaller and later ERP when subjects missed it than when they hit it.We also analyzed the event related spectral perturbation(ERSP)based on short-time Fourier transform,finding that the ?-band energy was significantly enhanced in the ‘miss' condition,while in the ‘hit' condition,the ?-band energy was significantly increased.We also extracted the characteristics of different cases signals during task and classified these features using TRCA algorithm.Finally,the average accuracy rate of target recognition improved 14.8%,with an average false positive rate of 4.6%.Next,this study proposed to enhance the human's ability of recognizing weak acoustic signals using tDCS.Ten young volunteers were recruited in the experiment,in which1.2 mA,15 min tDCS was applied to the forehead of subjects.We analyzed and compared the behavioral data between pre-and post-stimulation.It showed that the average response accuracy after tDCS was significantly 10.7% higherthan that before tDCS.And the late positive component amplitude of auditory ERP was significantly higher than sham stimulation.The ?-band energy decreased significantly after the stimulation.It was concluded that tDCS can improve the auditory recognition ability by regulating the excitability of cerebral cortex.In short,auditory perception experiments are designed to prove that the recognition ability of weak sound signals of brain-machine interaction system can be improved from the perspective of system performance promotion and brain cognitive function enhancement.The results laid a solid technical foundation for promoting the efficiency of auditory target recognition.