Abstract

The ability to detect single or bilateral double stimuli delivered simultaneously or sequentially was tested in 7 right-brain-damaged patients and in 7 healthy subjects. Experimental stimuli could be visual (red lights), tactile (non-noxious electric shocks) or visuo-tactile. Subjects were asked to report number (one or two), side (left or right), modality (tactile, visual or visuo-tactile) and sequence (simultaneous, first L or first R) of the stimuli. Whereas the performance of control subjects was almost perfect in all conditions, under double stimulation conditions patients failed to report contralesional stimuli in unimodal as well as in cross-modal combinations. This result suggests the existence of common attentional systems for integrating unimodal and cross-modal stimuli. Correct detection of controlesional tactile stimuli improved at the maximum interstimulus interval thus suggesting that temporal and not only spatial variables may influence extinction.