An Explorer Based On A Hybrid Brain Computer Interface

Brain-computer interfaces provide non-muscular communication and control by directlytranslating brain activities recorded from the scalp into computer control signals and thusenable users with motor disabilities to convey their intent to the external world. Generallyspeaking, BCI system using mixed two or more kinds of EEG signals has betterhuman-computer interaction capability compared to using of single mode signal. In this paper,we present a hybrid BCI system to operate the explorer with P300and motor imagery.Through this system, the user can access to his computer, the desktop and manipulate (open,close, copy, paste, delete) files such as documents, pictures, music, movies and so on. Thusthe system enriches the patients’s (such as paralysed patients) learning, living, entertainment,and improves their self-care ability.The explorer based on BCI is mainly composed of a BCI mouse, a BCI speller and anexplorer. BCI mouse is controlled by P300and motor imagery, which not only needs tocontrol the mouse movement freely, but also need to simulate the mouse to click, we call ittarget selection or rejection. P300controls the vertical movement, and motor imagery controlsthe horizontal movement of the mouse separately. The target selection or rejection isimplemented using a hybrid feature composed of the motor imagery and P300features.If the path has many folders in the explorer which you need to open, the mouse operationis complicated, the BCI mouse will be very complicated, the user can use address bar directlyinto a specified path with a P300speller.The system can finish some Windows Explorer’s basic functions. Firstly, the user canclick local disk and desktop directly into the path, and corresponding folders and files will beshown. Secondly, if the user clicks specified file in the list control, it will display a pop-upmenu for selection, so that the user can manipulate (open, copy, paste, delete) files. Thirdly,when specified file is opened, the user can click red close button to close the file. Finally, ifthe user wants to go into a path which contains many folders, the user is able to search forspecified path through address bar with P300speller. In the online experiment,5subjects were instructed to carry out the above six tasks forfour times. Subjects needed to perform at least twelve selections and input seven characters tocarry out the six tasks. The results of the experiment show subjects can successfully finishexperiment at average13.9selections and average8.15characters within average889.62s. Ina word, subjects can freely move, select an intended target and input text in the explorer withonly a small number of mistakes.Although our experimental results show that this BCI resource manager has realizedsome simple and basic functions, our system needs to be improved and extended in the future.Firstly, the control time of each trial is not short. The main reason is that detecting P300andtext inputting are time consuming, so improving the speed of the system is our future work.Secondly, we set the speed of the mouse according to the experience in this system, becausethe speed of the mouse also affects mouse control, we can the choice of speed based on acertain principle. Thirdly, we can extend several other functions for the system. Finally, it willbe of great interest to verify whether this system works for paralyzed subjects.