Studies of deaf or blind subjects often report enhanced perceptual abilities in the remaining senses. Compared to hearing subjects, psychophysical studies have revealed specific superior visual abilities in the early-deaf as well as enhanced auditory functions in the early-blind. The neural substrate for these superior sensory abilities has been hypothesized to reside in the deprived cerebral cortices that have been reorganized by the remaining sensory modalities through crossmodal plasticity. In this context, it has been proposed that auditory cortex of the deaf may be recruited to perform visual functions. However, a causal link between supranormal visual performance and the visual activity in the reorganized auditory cortex has never been demonstrated. Furthermore, if auditory cortex does mediate the enhanced visual abilities of the deaf, it is unknown if these functions are distributed uniformly across deaf auditory cortex, or if specific functions can be differentially localized to distinct portions of the affected cortices. These fundamental questions are of significant clinical importance now that restoration of hearing in prelingual deaf children is possible through cochlear prosthetics. Psychophysical, neuroanatomical, electrophysiological, and functional imaging studies will be described that demonstrate crossmodal plasticity in auditory cortex underlies the enhanced visual abilities of the early deaf.
Galit Buchs, Benedetta Heimler and Amir Amedi
Visual-to-auditory Sensory Substitution Devices (SSDs) are a family of non-invasive devices for visual rehabilitation aiming at conveying whole-scene visual information through the intact auditory modality. Although proven effective in lab environments, the use of SSDs has yet to be systematically tested in real-life situations. To start filling this gap, in the present work we tested the ability of expert SSD users to filter out irrelevant background noise while focusing on the relevant audio information. Specifically, nine blind expert users of the EyeMusic visual-to-auditory SSD performed a series of identification tasks via SSDs (i.e., shape, color, and conjunction of the two features). Their performance was compared in two separate conditions: silent baseline, and with irrelevant background sounds from real-life situations, using the same stimuli in a pseudo-random balanced design. Although the participants described the background noise as disturbing, no significant performance differences emerged between the two conditions (i.e., noisy; silent) for any of the tasks. In the conjunction task (shape and color) we found a non-significant trend for a disturbing effect of the background noise on performance. These findings suggest that visual-to-auditory SSDs can indeed be successfully used in noisy environments and that users can still focus on relevant auditory information while inhibiting irrelevant sounds. Our findings take a step towards the actual use of SSDs in real-life situations while potentially impacting rehabilitation of sensory deprived individuals.
Clare Jonas, Mary Jane Spiller, Paul B. Hibbard and Michael Proulx
and Schroeder, 2006 ). We are now in a position to consider how multisensory processing might differ between groups and between individuals — an important question for our understanding of neurodivergent conditions, ageing, and sensory loss. It was with this question in mind that we ran a series of
continue to limit) the uptake of all but the simplest tactile information transfer devices by humans (see also Alliusi, 1960 ; Loomis et al. , 2012 ), no matter whether they happen to be suffering from some form of sensory loss or not (Williams et al. , 2011 — see Note 2). It is worth acknowledging
Jutta Billino and Knut Drewing
Demographic changes in most developed societies have fostered research on functional aging. While cognitive changes have been characterized elaborately, understanding of perceptual aging lacks behind. We investigated age effects on the mechanisms of how multiple sources of sensory information are merged into a common percept. We studied visuo-haptic integration in a length discrimination task. A total of 24 young (20–25 years) and 27 senior (69–77 years) adults compared standard stimuli to appropriate sets of comparison stimuli. Standard stimuli were explored under visual, haptic, or visuo-haptic conditions. The task procedure allowed introducing an intersensory conflict by anamorphic lenses. Comparison stimuli were exclusively explored haptically. We derived psychometric functions for each condition, determining points of subjective equality and discrimination thresholds. We notably evaluated visuo-haptic perception by different models of multisensory processing, i.e., the Maximum-Likelihood-Estimate model of optimal cue integration, a suboptimal integration model, and a cue switching model. Our results support robust visuo-haptic integration across the adult lifespan. We found suboptimal weighted averaging of sensory sources in young adults, however, senior adults exploited differential sensory reliabilities more efficiently to optimize thresholds. Indeed, evaluation of the MLE model indicates that young adults underweighted visual cues by more than 30%; in contrast, visual weights of senior adults deviated only by about 3% from predictions. We suggest that close to optimal multisensory integration might contribute to successful compensation for age-related sensory losses and provides a critical resource. Differentiation between multisensory integration during healthy aging and age-related pathological challenges on the sensory systems awaits further exploration.
Per F. Nordmark, Per F. Nordmark, J. Andrew Pruszynski, Per F. Nordmark, J. Andrew Pruszynski and Roland S. Johansson
, Trends in Neurosciences 28 , 264 – 271 . Merabet L. B. Pascual-Leone A. ( 2010 ). Neural reorganization following sensory loss: the opportunity of change , Nature Reviews Neuroscience 11 , 44 – 52 . Schroeder C. E. Lindsley R. W. Specht C. Marcovici A. Smiley J
, 179 P pitch, 235, 319 placebo effect, 521 posture, 575 practice effects, 613 priors, 111 product memory, 347 R race model, 715 reaction time, 715 relative, 235 S saliency, 25 segregated attention, 145 sensorimotor integration, 671 sensory loss, 87 sensory marketing, 367 sensory substitution, 87 sign
Emiliano Ricciardi, Leonardo Tozzi, Andrea Leo and Pietro Pietrini
, heteromodal or cortico-cortical pathways that are unmasked or strengthened during visual loss (Desgent and Ptito, 2012 ; Kupers and Ptito, 2011 , 2013 ; Pascual-Leone et al ., 2005 ). Following sensory loss, the deprived visual cortical area is invaded by inputs originating from other sensory channels
Malika Auvray and Laurence R. Harris
never going to be the way to achieve full recovery of the use of a lost sense. Many researchers do however agree that a restricted form of sensory substitution can be achieved. Thus, it is undeniably the case that many abilities of people with sensory loss can be significantly enhanced by the use of SS
sensory loss in older adults: overview and rehabilitation directions , Disabil. Rehabil. 24 , 763 – 773 . Jansen S. D. Keebler J. R. Chaparro A. ( 2018 ). Shifts in maximum audiovisual integration with age , Multisens. Res. 31 , 191 – 212 . Lipsitz L. A. Jonsson P