A new (semantic) reflexive brain-computer interface: In search for a suitable classifier

作者:Furdea A*; Ruf C A; Halder S; De Massari D; Bogdan M; Rosenstiel W; Matuz T; Birbaumer N
来源:Journal of Neuroscience Methods, 2012, 203(1): 233-240.
DOI:10.1016/j.jneumeth.2011.09.013

摘要

The goal of the current study is to find a suitable classifier for electroencephalogram (EEG) data derived from a new learning paradigm which aims at communication in paralysis. A reflexive semantic classical (Pavlovian) conditioning paradigm is explored as an alternative to the operant learning paradigms, currently used in most brain-computer interfaces (BCIs). Comparable with a lie-detection experiment, subjects are presented with true and false statements. The EEG activity following true and false statements was classified with the aim to separate covert %26apos;yes%26apos; from covert %26apos;no%26apos; responses. %26lt;br%26gt;Four classification algorithms are compared for classifying off-line data collected from a group of 14 healthy participants: (i) stepwise linear discriminant analysis (SWLDA), (ii) shrinkage linear discriminant analysis (SLDA), (iii) linear support vector machine (LIN-SVM) and (iv) radial basis function kernel support vector machine (RBF-SVM). %26lt;br%26gt;The results indicate that all classifiers perform at chance level when separating conditioned %26apos;yes%26apos; from conditioned %26apos;no%26apos; responses. However, single conditioned reactions could be successfully classified on a single-trial basis (single conditioned reaction against a baseline interval). All of the four investigated classification methods achieve comparable performance, however results with RBF-SVM show the highest single-trial classification accuracy of 68.8%. The results suggest that the proposed paradigm may allow affirmative and negative (disapproving negative) communication in a BCI experiment.