Direct Brain-Computer Communication G. Pfurtscheller and R. Scherer Direct brain-computer communication is possible by analyzing and interpreting bioelectrical signals directly recorded from the brain. Such signals can be acquired either non-invasively by placing electrodes on the intact scalp and recording the electroencephalogram (EEG) or invasively by using subdural electrodes and recording the electrocorticogram (ECoG) or using intracortical electrodes and recording multiunit activity. Each type of cognitive activity such as e.g. imagination of a specific movement (motor imagery) or focussed visual attention, results in changes of oscillatory activity in EEG (ECoG). With a Brain-Computer Interface (BCI) such mentally induced changes can be detected, classified and transformed into a control signal. By using such a signal, a new communication channel for patients can be implemented or multimedia applications can be realized. An important aspect of BCI applications is the operation mode. When the user performs the mental task in response of a cue-stimulus, the analyses of the brain signal is limited to a predefined time window synchronous to the cue stimulus. Such a BCI system is called cue-based (computer-driven) and works in a synchronous mode. In the case where no cue stimulus is available, the brain signals have to be analyzed continuously sample-by-sample. Such a BCI system is called uncued (user-driven) and operates in an asynchronous mode. At this time, most BCI systems operate in a synchronous mode. More challenging and important in the future are BCI systems that work asynchronously. We will give an overview over the different types of BCI systems and introduce in detail two asynchronous BCI applications, one operating a "spelling device" for patients with Amyotrophic Lateral Sclerosis and the other used to restore hand grasp function via functional electrical stimulation (FES) in a tetraplegic patient. Furthermore, the use of Virtual Reality (VR) as optimal suitable feedback medium in BCI-applications will be discussed.