Visuo-tactile interactions in the congenitally deaf: a behavioral and event-related potential study

Abstract

Auditory deprivation is known to be accompanied by alterations in visual processing. Yet not much is known about tactile processing and the interplay of the intact sensory modalities in the deaf. We presented visual, tactile, and visuo-tactile stimuli to congenitally deaf and hearing individuals in a speeded detection task. Analyses of multisensory responses showed a redundant signals effect that was attributable to a coactivation mechanism in both groups, although the redundancy gain was less in the deaf. In line with these behavioral results, on a neural level, there were multisensory interactions in both groups that were again weaker in the deaf. In hearing but not deaf participants, somatosensory event-related potential N200 latencies were modulated by simultaneous visual stimulation. A comparison of unisensory responses between groups revealed larger N200 amplitudes for visual and shorter N200 latencies for tactile stimuli in the deaf. Furthermore, P300 amplitudes were also larger in the deaf. This group difference was significant for tactile and approached significance for visual targets. The differences in visual and tactile processing between deaf and hearing participants, however, were not reflected in behavior. Both the behavioral and electroencephalography (EEG) results suggest more pronounced multisensory interaction in hearing than in deaf individuals. Visuo-tactile enhancements could not be explained by perceptual deficiency, but could be partly attributable to inverse effectiveness.

Vibrotactile Discrimination Training Affects Brain Connectivity in Profoundly Deaf Individuals

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Auditory cross-modal reorganization in cochlear implant users indicates audio-visual integration

“…Sensors were equidistantly placed. Electrode placement included infra-cerebral spatial sampling, which aims to facilitate source localization efforts due to a better coverage of the head sphere compared to traditional 10–20 electrode layouts ( Debener et al, 2008 , Hauthal et al, 2014 , Hine et al, 2008 , Hine and Debener, 2007 ). A central fronto-polar site was used as ground and the nose-tip as reference.…”

Enhanced audio–visual interactions in the auditory cortex of elderly cochlear-implant users

“…To eliminate effects of this inherent activity, the time-locked average of the no stimulus (nostim) condition was added to the left side of the equation, leading to: AV þ nostim ¼ A þ V (see e.g. Hauthal et al, 2015;Mishra et al, 2010Mishra et al, , 2007Senkowski et al, 2011;Talsma and Woldorff, 2005). Afterward, the equation of the additive model was rearranged to A ¼ AV þ nostim À V. This allowed comparing the recorded response to unisensory auditory stimuli (referred to as A uni ) and the term [AV þ nostim À V].…”