@ARTICLE{HoeSchBlaTan11,
    author = {H\"ohne, Johannes and Schreuder, Martijn and Blankertz, Benjamin and Tangermann, Michael},
    title = "A novel 9-class auditory {ERP} paradigm driving a predictive text entry system",
    journal = "Frontiers in neuroscience",
    year = "2011",
    volume = "5",
    pages = "99",
    note = "Open Access",
    folder = "BBCI",
    URL = "http://journal.frontiersin.org/article/10.3389/fnins.2011.00099",
    DOI = "10.3389/fnins.2011.00099",
    ISSN = "1662-453X",
    ABSTRACT = "Brain-Computer Interfaces (BCIs) based on Event Related Potentials (ERPs) strive for offering communication pathways which are independent of muscle activity. While most visual ERP-based BCI paradigms require good control of the user's gaze direction, auditory BCI paradigms overcome this restriction. The present work proposes a novel approach using Auditory Evoked Potentials (AEP) for the example of a multiclass text spelling application. To control the ERP speller, BCI users focus their attention to two-dimensional auditory stimuli that vary in both, pitch (high/medium/low) and direction (left/middle/right) and that are presented via headphones. The resulting nine different control signals are exploited to drive a predictive text entry system. It enables the user to spell a letter by a single 9-class decision plus two additional decisions to confirm a spelled word. This paradigm - called PASS2D - was investigated in an online study with twelve healthy participants. Users spelled with more than 0.8 characters per minute on average (3.4 bits per minute) which makes PASS2D a competitive method. It could enrich the toolbox of existing ERP paradigms for BCI end users like late-stage ALS patients."
}