Brain-Computer Interface Systems Used for Virtual Reality Control

Abstract

A Brain-Computer Interface (BCI) is a non-muscular communication channel for connecting the brain to a computer or another device. Currently, non-invasive BCIs transform thoughtrelated changes in the electroencephalogram (EEG) online and in real time into control signals. In such an EEG-based BCI, specific features are extracted from brain-signals, transformed into a control signal, and used to restore communication to patients with locked-in-syndrome or to control neuroprosthesis in patients with spinal cord injuries (Birbaumer et al., 1999; Pfurtscheller et al., 2008b; Wolpaw et al., 2002). In addition to these applications, which focus on communication and control, the related field of neurofeedback supports feedback training in people suffering from epilepsy, autism, stroke, and emotional or attentional disorders (Birbaumer & Cohen, 2007). Today the world of BCI applications is expanding and new fields are opening. One new direction involves BCIs to control virtual reality (VR), including BCIs for games, or using VR as a powerful feedback medium to reduce the need for BCI training (Leeb et al., 2007b; Scherer et al., 2008). Virtual environments (VE) can provide an excellent testing ground for procedures that could be adapted to real world scenarios, especially for patients with disabilities. If people can learn to control their movements or perform specific tasks in a VE, this could justify the much greater expense of building physical devices such as a wheelchair or robot arm that is controlled by a BCI. BCIs are more and more moving out of the laboratory and becoming also useful for healthy users in certain situations (Nijholt et al., 2008). One of the first efforts to combine VR and BCI technologies was Bayliss and Ballard (2000) and Bayliss (2003). They introduced a VR smart home in which users could control different appliances using a P300-based BCI. Pineda et al. (2003) showed that immersive feedback based on a computer game can help people learn to control a BCI based on imagined movement more quickly than mundane feedback, a finding we later validated with other immersive feedback (Leeb et al., 2006; 2007b). Lalor et al. (2005) used a steady-state visual evoked potential (SSVEP)-based BCI to control a character in an immersive 3-D gaming environment. Recently, Leeb et al. (2007b) have reported on exploring a smart virtual