Communication using non-invasive brain-computer interface system

Abstract

Introduction : In the present study, we developed a brain-computer interface（BCI）system that used surface electroencephalographic（EEG）signals recorded over the sensorimotor cortex to investigate long-term effects of BCI use on brain activities in people with severe motor disability. Method : The BCI system estimated the user’s motor intention（MI）in 3 different limb movements : feet, left hand, and right hand detecting event related desynchronization（ERD）in the mu band （around 10 Hz）and event related synchronization（ERS）in beta band（around 20 Hz）. To investigate the long-term effects, we followed BCI use by a chronic tetraplegic subject with muscular dystrophy for a half of a year. Result : The subject was trained to control his avatar via the BCI by strolling in the VR for 1 hour a day and then continued the same training twice a month at his home. We observed changes in ERD and ERS patterns and increases in BCI performance over long-term use of this system. At last, the subject freely strolled and communicated with others users in a virtual world using our BCI system. Discussion : Our results suggest that it is possible to develop BCI systems that allow severely paralyzed patients to communicate with others in a virtual world in the same way as a healthy person. The present study also revealed that long-term of BCI use caused plastic change of brain activities. This result suggested the possibility that BCI can be not only a substitute of a part of body but also a rehabilitation tool.