%0 Journal Article %J Epilepsy Behav %D 2008 %T Voluntary brain regulation and communication with electrocorticogram signals. %A Hinterberger, T. %A Widman, Guido %A Lal, T.N %A Jeremy Jeremy Hill %A Tangermann, Michael %A Rosenstiel, W. %A Schölkopf, B %A Elger, Christian %A Niels Birbaumer %K Adult %K Biofeedback, Psychology %K Cerebral Cortex %K Communication Aids for Disabled %K Dominance, Cerebral %K Electroencephalography %K Epilepsies, Partial %K Female %K Humans %K Imagination %K Male %K Middle Aged %K Motor Activity %K Motor Cortex %K Signal Processing, Computer-Assisted %K Software %K Somatosensory Cortex %K Theta Rhythm %K User-Computer Interface %K Writing %X

Brain-computer interfaces (BCIs) can be used for communication in writing without muscular activity or for learning to control seizures by voluntary regulation of brain signals such as the electroencephalogram (EEG). Three of five patients with epilepsy were able to spell their names with electrocorticogram (ECoG) signals derived from motor-related areas within only one or two training sessions. Imagery of finger or tongue movements was classified with support-vector classification of autoregressive coefficients derived from the ECoG signals. After training of the classifier, binary classification responses were used to select letters from a computer-generated menu. Offline analysis showed increased theta activity in the unsuccessful patients, whereas the successful patients exhibited dominant sensorimotor rhythms that they could control. The high spatial resolution and increased signal-to-noise ratio in ECoG signals, combined with short training periods, may offer an alternative for communication in complete paralysis, locked-in syndrome, and motor restoration.

%B Epilepsy Behav %V 13 %P 300-6 %8 08/2008 %G eng %U http://www.ncbi.nlm.nih.gov/pubmed/18495541 %N 2 %R 10.1016/j.yebeh.2008.03.014 %0 Journal Article %J IEEE Trans Neural Syst Rehabil Eng %D 2006 %T Classifying EEG and ECoG signals without subject training for fast BCI implementation: comparison of nonparalyzed and completely paralyzed subjects. %A Jeremy Jeremy Hill %A Lal, T.N %A Schröder, Michael %A Hinterberger, T. %A Wilhelm, Barbara %A Nijboer, F %A Mochty, Ursula %A Widman, Guido %A Elger, Christian %A Schölkopf, B %A Kübler, A. %A Niels Birbaumer %K Algorithms %K Artificial Intelligence %K Cluster Analysis %K Computer User Training %K Electroencephalography %K Evoked Potentials %K Female %K Humans %K Imagination %K Male %K Middle Aged %K Paralysis %K Pattern Recognition, Automated %K User-Computer Interface %X

We summarize results from a series of related studies that aim to develop a motor-imagery-based brain-computer interface using a single recording session of electroencephalogram (EEG) or electrocorticogram (ECoG) signals for each subject. We apply the same experimental and analytical methods to 11 nonparalysed subjects (eight EEG, three ECoG), and to five paralyzed subjects (four EEG, one ECoG) who had been unable to communicate for some time. While it was relatively easy to obtain classifiable signals quickly from most of the nonparalyzed subjects, it proved impossible to classify the signals obtained from the paralyzed patients by the same methods. This highlights the fact that though certain BCI paradigms may work well with healthy subjects, this does not necessarily indicate success with the target user group. We outline possible reasons for this failure to transfer.

%B IEEE Trans Neural Syst Rehabil Eng %V 14 %P 183-6 %8 06/2006 %G eng %U http://www.ncbi.nlm.nih.gov/pubmed/16792289 %N 2 %R 10.1109/TNSRE.2006.875548 %0 Journal Article %J EURASIP Journal on Advances in Signal Processing %D 2005 %T Robust EEG Channel Selection across Subjects for Brain-Computer Interfaces. %A Schröder, Michael %A Lal, T.N %A Hinterberger, T. %A Bogdan, Martin %A Jeremy Jeremy Hill %A Niels Birbaumer %A Rosenstiel, W. %A Schölkopf, B %E Vesin J M, T EbrahimiEditor %K brain-computer interface %K channel selection %K Electroencephalography %K feature selection %K recursive channel elimination %K support vector machine %X

Most EEG-based brain-computer interface (BCI) paradigms come along with specific electrode positions, for example, for a visual-based BCI, electrode positions close to the primary visual cortex are used. For new BCI paradigms it is usually not known where task relevant activity can be measured from the scalp. For individual subjects, Lal et al. in 2004 showed that recording positions can be found without the use of prior knowledge about the paradigm used. However it remains unclear to what extent their method of recursive channel elimination (RCE) can be generalized across subjects. In this paper we transfer channel rankings from a group of subjects to a new subject. For motor imagery tasks the results are promising, although cross-subject channel selection does not quite achieve the performance of channel selection on data of single subjects. Although the RCE method was not provided with prior knowledge about the mental task, channels that are well known to be important (from a physiological point of view) were consistently selected whereas task-irrelevant channels were reliably disregarded.

%B EURASIP Journal on Advances in Signal Processing %V 2005 %P 3103–3112 %8 01/2005 %G eng %U http://www.researchgate.net/publication/26532072_Robust_EEG_Channel_Selection_across_Subjects_for_Brain-Computer_Interfaces %R 10.1155/ASP.2005.3103 %0 Journal Article %J IEEE Trans Biomed Eng %D 2004 %T The BCI Competition 2003: Progress and perspectives in detection and discrimination of EEG single trials. %A Benjamin Blankertz %A Müller, Klaus-Robert %A Curio, Gabriel %A Theresa M Vaughan %A Gerwin Schalk %A Jonathan Wolpaw %A Schlögl, Alois %A Neuper, Christa %A Pfurtscheller, Gert %A Hinterberger, T. %A Schröder, Michael %A Niels Birbaumer %K Adult %K Algorithms %K Amyotrophic Lateral Sclerosis %K Artificial Intelligence %K Brain %K Cognition %K Databases, Factual %K Electroencephalography %K Evoked Potentials %K Humans %K Reproducibility of Results %K Sensitivity and Specificity %K User-Computer Interface %X Interest in developing a new method of man-to-machine communication--a brain-computer interface (BCI)--has grown steadily over the past few decades. BCIs create a new communication channel between the brain and an output device by bypassing conventional motor output pathways of nerves and muscles. These systems use signals recorded from the scalp, the surface of the cortex, or from inside the brain to enable users to control a variety of applications including simple word-processing software and orthotics. BCI technology could therefore provide a new communication and control option for individuals who cannot otherwise express their wishes to the outside world. Signal processing and classification methods are essential tools in the development of improved BCI technology. We organized the BCI Competition 2003 to evaluate the current state of the art of these tools. Four laboratories well versed in EEG-based BCI research provided six data sets in a documented format. We made these data sets (i.e., labeled training sets and unlabeled test sets) and their descriptions available on the Internet. The goal in the competition was to maximize the performance measure for the test labels. Researchers worldwide tested their algorithms and competed for the best classification results. This paper describes the six data sets and the results and function of the most successful algorithms. %B IEEE Trans Biomed Eng %V 51 %P 1044-51 %8 06/2004 %G eng %N 6 %R 10.1109/TBME.2004.826692 %0 Journal Article %J IEEE Trans Biomed Eng %D 2004 %T BCI2000: a general-purpose brain-computer interface (BCI) system. %A Gerwin Schalk %A Dennis J. McFarland %A Hinterberger, T. %A Niels Birbaumer %A Jonathan Wolpaw %K Algorithms %K Brain %K Cognition %K Communication Aids for Disabled %K Computer Peripherals %K Electroencephalography %K Equipment Design %K Equipment Failure Analysis %K Evoked Potentials %K Humans %K Systems Integration %K User-Computer Interface %X Many laboratories have begun to develop brain-computer interface (BCI) systems that provide communication and control capabilities to people with severe motor disabilities. Further progress and realization of practical applications depends on systematic evaluations and comparisons of different brain signals, recording methods, processing algorithms, output formats, and operating protocols. However, the typical BCI system is designed specifically for one particular BCI method and is, therefore, not suited to the systematic studies that are essential for continued progress. In response to this problem, we have developed a documented general-purpose BCI research and development platform called BCI2000. BCI2000 can incorporate alone or in combination any brain signals, signal processing methods, output devices, and operating protocols. This report is intended to describe to investigators, biomedical engineers, and computer scientists the concepts that the BC12000 system is based upon and gives examples of successful BCI implementations using this system. To date, we have used BCI2000 to create BCI systems for a variety of brain signals, processing methods, and applications. The data show that these systems function well in online operation and that BCI2000 satisfies the stringent real-time requirements of BCI systems. By substantially reducing labor and cost, BCI2000 facilitates the implementation of different BCI systems and other psychophysiological experiments. It is available with full documentation and free of charge for research or educational purposes and is currently being used in a variety of studies by many research groups. %B IEEE Trans Biomed Eng %V 51 %P 1034-43 %8 06/2004 %G eng %N 6 %R 10.1109/TBME.2004.827072