Brain-Computer Interfaces for Virtual Environment Control

摘要

A brain-computer Interface (BCI) is a new communication channel between the human brain and a digital computer. Furthermore a BCI enables communication without using any muscle activity for a subject. The ambitious goal of a BCI is finally the restoration of movements, communication and environmental control for handicapped people. However, in more recent research also BCI control in combination with Virtual Environments (VE) gains more and more interest. Within this study we present experiments combining BCI systems and control VE for navigation and control purposes just by thoughts. A comparison of the applicability and reliability of different BCI types based on event related potentials (P300 approach) will be presented. BCI experiments for navigation in VR were conducted so far with (i) synchronous BCI and (ii) asynchronous BCI systems. A synchronous BCI analyzes the EEG patterns in a predefined time window and has 2-3 degrees of freedom. A asynchronous BCI analyzes the EEG signal continuously and if a specific event is detected then a control signal is generated. This study is focused on a BCI system that can be realized for Virtual Reality (VR) control with a high degree of freedom and high information transfer rate. Therefore a P300 based human computer interface has been developed in a VR implementation of a smart home for controlling, the environment (television, music, telephone calls) and navigation control in the house. Results show that the new P300 based BCI system allows a very reliable control of the VR system. Of special importance is the possibility to select very rapidly the specific command out of many different choices. This eliminates the usage of decision trees as previously done with BCI systems.