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Abstract

The aim of the study was to investigate the applicability of a semantic conditioning
paradigm in a BCI setting to enable basic yes/no communication. The experiment
consisted of two phases: acquisition and extinction. In the first block of the acquisition phase, true and false sentences were randomly presented in an auditory fashion. The conditioned stimuli (CS) comprised thinking on either ‘‘yes’’ or ‘‘no’’, according to the type of the sentence. For ‘‘yes’’ and ‘‘no’’ conditioning two different unconditioned stimuli (UCS) were used: a pink noise - immediately following a true sentence and a white noise - following a false sentence. In the next two blocks, one of every 10th CS, respectively, one of every 5th CS, at random, was not paired with the UCS. Physiological responses were continuously measured by means of electroencephalogram, electrocardiogram
and galvanic skin response. The Self AssessmentManikin scale was used
to assess the valence and the arousal that each subject associated to its affective reaction to UCS. Ten healthy subjects were measured with preliminary results suggesting differentiable responses for the CS. Further analysis will be carried out to assess conditioned reaction. The employment of the auditory modality and of a paradigm which consumes fewer attentional resources and voluntary effortsmay be an alternative for the locked-in patients to learn BCI skills and to transfer these to the completely locked-in state (CLIS). To confirm these we intend to carry out a longitudinal study.