Haptic spatial configuration learning in deaf and hearing individuals

Somatosensory processing in deaf and deafblind individuals: How does the brain adapt as a function of sensory and linguistic experience? A critical review

How do deaf and deafblind individuals process touch? This question offers a unique model to understand the prospects and constraints of neural plasticity. Our brain constantly receives and processes signals from the environment and combines them into the most reliable information content. The nervous system adapts its functional and structural organization according to the input, and perceptual processing develops as a function of individual experience. However, there are still many unresolved questions regarding the deciding factors for these changes in deaf and deafblind individuals, and so far, findings are not consistent. To date, most studies have not taken the sensory and linguistic experiences of the included participants into account. As a result, the impact of sensory deprivation vs. language experience on somatosensory processing remains inconclusive. Even less is known about the impact of deafblindness on brain development. The resulting neural adaptations could be even more substantial, but no clear patterns have yet been identified. How do deafblind individuals process sensory input? Studies on deafblindness have mostly focused on single cases or groups of late-blind individuals. Importantly, the language backgrounds of deafblind communities are highly variable and include the usage of tactile languages. So far, this kind of linguistic experience and its consequences have not been considered in studies on basic perceptual functions. Here, we will provide a critical review of the literature, aiming at identifying determinants for neuroplasticity and gaps in our current knowledge of somatosensory processing in deaf and deafblind individuals.

The Impact of Aging on Spatial Abilities in Deaf Users of a Sign Language

Research involving the general population of people who use a spoken language to communicate has demonstrated that older adults experience cognitive and physical changes associated with aging. Notwithstanding the differences in the cognitive processes involved in sign and spoken languages, it is possible that aging can also affect cognitive processing in deaf signers. This research aims to explore the impact of aging on spatial abilities among sign language users. Results showed that younger signers were more accurate than older signers on all spatial tasks. Therefore, the age-related impact on spatial abilities found in the older hearing population can be generalized to the population of signers. Potential implications for sign language production and comprehension are discussed.

Neurocognitive Functioning of Sport Climbers

Sport climbing, included in the programme of the Tokyo 2020 Summer Olympic Games, is increasingly gaining in popularity as a method of physical and mental health enhancement. Studies show a positive relationship between climbing and improvement of neurocognitive functioning. The aim of this study was to determine the differences in neurocognitive indicators: time of testing, memory, and location between climbers and non-climbers. The sample comprised 30 sport climbers (15 males, 15 females; aged 25 ± 4 years) practicing climbing regularly for five years, and 30 non-climbing age- and sex-matched controls. The Tactual Performance Test (Halstead-Reitan Test Battery) was used to measure neurocognitive functions (tactile-spatial functions, motion coordination, kinesthetic abilities, learning, memory). Significant differences were found between sport climbers and controls in reference to time, memory, and location (p < 0.05). Climbers reached higher memory as well as location ratios and lower time ratios in comparison to controls. Different strategies used to complete the task between the two groups were observed. The neurocognitive functioning of sport climbers manifests itself in faster recognition and differentiation of tactile input and better spatial perception, tactile perception, and movement memory.

Numerical and Real-World Estimation Abilities of Deaf and Hearing College Students

Various studies have examined possible loci of deaf learners' documented challenges with regard to reading, usually focusing on language-related factors. Deaf students also frequently struggle in mathematics and science, but fewer studies have examined possible reasons for those difficulties. The present study examined numerical and non-numerical (real-world) estimation skills among deaf and hearing college students, together with several cognitive abilities likely to underlie mathematics performance. Drawing on claims in the literature and some limited evidence from research involving deaf children, the study also considered the possibility that the use of sign language and/or the use of cochlear implants and spoken language might facilitate deaf college students' estimation skills and mathematics achievement more broadly. Results indicated relatively little impact of cochlear implant use or language modality on either estimation skills or overall mathematics ability. Predictors of those abilities differed for deaf and hearing learners. Results suggest the need to guard against overgeneralisations either within the diverse population of deaf learners or between deaf and hearing learners. They further emphasise the need for evidence-based practice in mathematics instruction appropriate for older deaf learners, rather than making assumptions from studies involving younger or narrowly-selected samples.

Don't Assume Deaf Students are Visual Learners

In the education of deaf learners, from primary school to postsecondary settings, it frequently is suggested that deaf students are visual learners. That assumption appears to be based on the visual nature of signed languages-used by some but not all deaf individuals-and the fact that with greater hearing losses, deaf students will rely relatively more on vision than audition. However, the questions of whether individuals with hearing loss are more likely to be visual learners than verbal learners or more likely than hearing peers to be visual learners have not been empirically explored. Several recent studies, in fact, have indicated that hearing learners typically perform as well or better than deaf learners on a variety of visual-spatial tasks. The present study used two standardized instruments to examine learning styles among college deaf students who primarily rely on sign language or spoken language and their hearing peers. The visual-verbal dimension was of particular interest. Consistent with recent indirect findings, results indicated that deaf students are no more likely than hearing students to be visual learners and are no stronger in their visual skills and habits than their verbal skills and habits, nor are deaf students' visual orientations associated with sign language skills. The results clearly have specific implications for the educating of deaf learners.

Effects of Hearing Status and Sign Language Use on Working Memory

Deaf individuals have been found to score lower than hearing individuals across a variety of memory tasks involving both verbal and nonverbal stimuli, particularly those requiring retention of serial order. Deaf individuals who are native signers, meanwhile, have been found to score higher on visual-spatial memory tasks than on verbal-sequential tasks and higher on some visual-spatial tasks than hearing nonsigners. However, hearing status and preferred language modality (signed or spoken) frequently are confounded in such studies. That situation is resolved in the present study by including deaf students who use spoken language and sign language interpreting students (hearing signers) as well as deaf signers and hearing nonsigners. Three complex memory span tasks revealed overall advantages for hearing signers and nonsigners over both deaf signers and deaf nonsigners on 2 tasks involving memory for verbal stimuli (letters). There were no differences among the groups on the task involving visual-spatial stimuli. The results are consistent with and extend recent findings concerning the effects of hearing status and language on memory and are discussed in terms of language modality, hearing status, and cognitive abilities among deaf and hearing individuals.

Understanding Language, Hearing Status, and Visual-Spatial Skills

It is frequently assumed that deaf individuals have superior visual-spatial abilities relative to hearing peers and thus, in educational settings, they are often considered visual learners. There is some empirical evidence to support the former assumption, although it is inconsistent, and apparently none to support the latter. Three experiments examined visual-spatial and related cognitive abilities among deaf individuals who varied in their preferred language modality and use of cochlear implants (CIs) and hearing individuals who varied in their sign language skills. Sign language and spoken language assessments accompanied tasks involving visual-spatial processing, working memory, nonverbal logical reasoning, and executive function. Results were consistent with other recent studies indicating no generalized visual-spatial advantage for deaf individuals and suggested that their performance in that domain may be linked to the strength of their preferred language skills regardless of modality. Hearing individuals performed more strongly than deaf individuals on several visual-spatial and self-reported executive functioning measures, regardless of sign language skills or use of CIs. Findings are inconsistent with assumptions that deaf individuals are visual learners or are superior to hearing individuals across a broad range of visual-spatial tasks. Further, performance of deaf and hearing individuals on the same visual-spatial tasks was associated with differing cognitive abilities, suggesting that different cognitive processes may be involved in visual-spatial processing in these groups.