Brain–computer interfaces for EEG neurofeedback: Peculiarities and solutions

• BCIs for neurofeedback received much interest in applied clinical sciences.
• User groups and experimental designs differentiate them from other BCIs.
• BCI software is discussed in terms of its usability for neurofeedback.
• Peculiarities did not yet sufficiently impact research agendas and software design.
• A software (NeuroFeedback Suite 1.0) is introduced addressing some of these issues.

Neurofeedback training procedures designed to alter a person's brain activity have been in use for nearly four decades now and represent one of the earliest applications of brain–computer interfaces (BCI). The majority of studies using neurofeedback technology relies on recordings of the electroencephalogram (EEG) and applies neurofeedback in clinical contexts, exploring its potential as treatment for psychopathological syndromes. This clinical focus significantly affects the technology behind neurofeedback BCIs. For example, in contrast to other BCI applications, neurofeedback BCIs usually rely on EEG-derived features with only a minimum of additional processing steps being employed. Here, we highlight the peculiarities of EEG-based neurofeedback BCIs and consider their relevance for software implementations. Having reviewed already existing packages for the implementation of BCIs, we introduce our own solution which specifically considers the relevance of multi-subject handling for experimental and clinical trials, for example by implementing ready-to-use solutions for pseudo-/sham-neurofeedback.