A Positive Relationship Between Sign Language Comprehension and Mental Rotation Abilities

Geometry in the brain optimized for sign language - A unique role of the anterior superior parietal lobule in deaf signers

Geometry has been identified as a cognitive domain where deaf individuals exhibit relative strength, yet the neural mechanisms underlying geometry processing in this population remain poorly understood. This fMRI study aimed to investigate the neural correlates of geometry processing in deaf and hearing individuals. Twenty-two adult deaf signers and 25 hearing non-signers completed a geometry decision task. We found no group differences in performance, while there were some differences in parietal activation. As expected, the posterior superior parietal lobule (SPL) was recruited for both groups. The anterior SPL was significantly more activated in the deaf group, and the inferior parietal lobule was significantly more deactivated in the hearing group. In conclusion, despite similar performance across groups, there were differences in the recruitment of parietal regions. These differences may reflect inherent differences in brain organization due to different early sensory and linguistic experiences.

Viewing angle matters in British Sign Language processing

The impact of adverse listening conditions on spoken language perception is well established, but the role of suboptimal viewing conditions on signed language processing is less clear. Viewing angle, i.e. the physical orientation of a perceiver relative to a signer, varies in many everyday deaf community settings for L1 signers and may impact comprehension. Further, processing from various viewing angles may be more difficult for late L2 learners of a signed language, with less variation in sign input while learning. Using a semantic decision task in a distance priming paradigm, we show that British Sign Language signers are slower and less accurate to comprehend signs shown from side viewing angles, with L2 learners in particular making disproportionately more errors when viewing signs from side angles. We also investigated how individual differences in mental rotation ability modulate processing signs from different angles. Speed and accuracy on the BSL task correlated with mental rotation ability, suggesting that signers may mentally represent signs from a frontal view, and use mental rotation to process signs from other viewing angles. Our results extend the literature on viewpoint specificity in visual recognition to linguistic stimuli. The data suggests that L2 signed language learners should maximise their exposure to diverse signed language input, both in terms of viewing angle and other difficult viewing conditions to maximise comprehension.

Health-related quality of life and associated developmental domains of children provided early with cochlear implants

OBJECTIVES

Quality of life plays an important place in the psychosocial development of children with Cochlear Implants (CI). We assesd health-related quality of life (HRQoL) in children with CI and in hearing children and determined relationships between HRQoL and other developmental characteristics (social-emotional development, Theory of Mind (ToM), spoken language skills).

METHODS

A longitudinal study was conducted including children with CI and hearing children. We used instruments that are widely employed and have been validated for research. At time 1 social-emotional development, ToM and spoken language skills were assessed.HRQoL was assessed using the generic KINDL questionnaire, as was social-emotional development, 2.5 years later (time 2).

RESULTS

No significant difference was seen in HRQoL between hearing children and children with CI. We show that the age of detection, the age of hearing care, and the start of early intervention are not related to HRQoL of children with CI, but relationships with some domains of social-emotional development are evident.

CONCLUSIONS

This study highlights the importance of targeted intervention not only to improve spoken language skills at preschool age, but also strengthen social-emotional and social-cognitive competences.

Ten things you should know about sign languages

The ten things you should know about sign languages are the following. 1) Sign languages have phonology and poetry. 2) Sign languages vary in their linguistic structure and family history, but share some typological features due to their shared biology (manual production). 3) Although there are many similarities between perceiving and producing speech and sign, the biology of language can impact aspects of processing. 4) Iconicity is pervasive in sign language lexicons and can play a role in language acquisition and processing. 5) Deaf and hard-of-hearing children are at risk for language deprivation. 6) Signers gesture when signing. 7) Sign language experience enhances some visual-spatial skills. 8) The same left hemisphere brain regions support both spoken and sign languages, but some neural regions are specific to sign language. 9) Bimodal bilinguals can code-blend, rather code-switch, which alters the nature of language control. 10) The emergence of new sign languages reveals patterns of language creation and evolution. These discoveries reveal how language modality does and does not affect language structure, acquisition, processing, use, and representation in the brain. Sign languages provide unique insights into human language that cannot be obtained by studying spoken languages alone.

Verbal, Figural, and Arithmetic Fluency of Children with Cochlear Implants

Cochlear implantation gives children with prelingual severe hearing loss and deafness the opportunity to develop their hearing abilities, speech, language, cognitive abilities and academic skills with adequate rehabilitation. The aim of the research was to analyze verbal, figural and arithmetic fluency and their interrelationship in children with a cochlear implant (CI) and children with normal hearing (NH). A total of 46 children with CI and 110 children with NH, aged 9 to 16, participated in the research. Verbal fluency was assessed using phonemic and semantic fluency, and non-verbal fluency using figural fluency. Arithmetic fluency was assessed using simple arithmetic tasks within the number range up to 100. The results showed that children with CI achieved poorer results in phonemic fluency (z = -4.92; p < 0.001), semantic fluency (z = -3.89; p < 0.001), figural fluency (z = -3.07; p = 0.002), and arithmetic fluency (z = -4.27; p < 0.001). In both groups, a positive correlation was obtained between the measured modalities and types of fluency. In the group of children with CI, a sex difference was obtained on the phonemic fluency test, in favor of girls. The age of children with CI was correlated with arithmetic fluency. Verbal, figural and arithmetic fluency of children with CI speak in favor of the importance of early auditory and language experiences.

Over-reliance on English hinders cognitive science

English is the dominant language in the study of human cognition and behavior: the individuals studied by cognitive scientists, as well as most of the scientists themselves, are frequently English speakers. However, English differs from other languages in ways that have consequences for the whole of the cognitive sciences, reaching far beyond the study of language itself. Here, we review an emerging body of evidence that highlights how the particular characteristics of English and the linguistic habits of English speakers bias the field by both warping research programs (e.g., overemphasizing features and mechanisms present in English over others) and overgeneralizing observations from English speakers' behaviors, brains, and cognition to our entire species. We propose mitigating strategies that could help avoid some of these pitfalls.

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.

Language aptitude in the visuospatial modality: L2 British Sign Language acquisition and cognitive skills in British Sign Language-English interpreting students

Sign language interpreting (SLI) is a cognitively challenging task performed mostly by second language learners (i.e., not raised using a sign language as a home language). SLI students must first gain language fluency in a new visuospatial modality and then move between spoken and signed modalities as they interpret. As a result, many students plateau before reaching working fluency, and SLI training program drop-out rates are high. However, we know little about the requisite skills to become a successful interpreter: the few existing studies investigating SLI aptitude in terms of linguistic and cognitive skills lack baseline measures. Here we report a 3-year exploratory longitudinal skills assessments study with British Sign Language (BSL)-English SLI students at two universities (n = 33). Our aims were two-fold: first, to better understand the prerequisite skills that lead to successful SLI outcomes; second, to better understand how signing and interpreting skills impact other aspects of cognition. A battery of tasks was completed at four time points to assess skills, including but not limited to: multimodal and unimodal working memory, 2-dimensional and 3-dimensional mental rotation (MR), and English comprehension. Dependent measures were BSL and SLI course grades, BSL reproduction tests, and consecutive SLI tasks. Results reveal that initial BSL proficiency and 2D-MR were associated with selection for the degree program, while visuospatial working memory was linked to continuing with the program. 3D-MR improved throughout the degree, alongside some limited gains in auditory, visuospatial, and multimodal working memory tasks. Visuospatial working memory and MR were the skills closest associated with BSL and SLI outcomes, particularly those tasks involving sign language production, thus, highlighting the importance of cognition related to the visuospatial modality. These preliminary data will inform SLI training programs, from applicant selection to curriculum design.

Perceiving fingerspelling via point-light displays: The stimulus and the perceiver both matter

Signed languages such as American Sign Language (ASL) rely on visuospatial information that combines hand and bodily movements, facial expressions, and fingerspelling. Signers communicate in a wide array of sub-optimal environments, such as in dim lighting or from a distance. While fingerspelling is a common and essential part of signed languages, the perception of fingerspelling in difficult visual environments is not well understood. The movement and spatial patterns of ASL are well-suited to representation by dynamic Point Light Display (PLD) stimuli in which human movement is shown as an array of moving dots affixed to joints on the body. We created PLD videos of fingerspelled location names. The location names were either Real (e.g., KUWAIT) or Pseudo-names (e.g., CLARTAND), and the PLDs showed either a High or a Low number of markers. In an online study, Deaf and Hearing ASL users (total N = 283) watched 27 PLD stimulus videos that varied by Word Type and Number of Markers. Participants watched the videos and typed the names they saw, along with how confident they were in their response. We predicted that when signers see ASL fingerspelling PLDs, language experience in ASL will be positively correlated with accuracy and self-rated confidence scores. We also predicted that Real location names would be understood better than Pseudo names. Our findings supported those predictions. We also discovered a significant interaction between Age and Word Type, which suggests that as people age, they use outside world knowledge to inform their fingerspelling success. Finally, we examined the accuracy and confidence in fingerspelling perception in early ASL users. Studying the relationship between language experience with PLD fingerspelling perception allows us to explore how hearing status, ASL fluency levels, and age of language acquisition affect the core abilities of understanding fingerspelling.

Evidence for superior encoding of detailed visual memories in deaf signers

Recent evidence shows that deaf signers outperform hearing non-signers in some tests of visual attention and discrimination. Furthermore, they can retain visual information better over short periods, i.e., seconds. However, it is unknown if deaf signers’ retention of detailed visual information is superior following more extended periods. We report a study investigating this possibility. Our data revealed that deaf individuals outperformed hearing people in a visual long-term memory test that probed the fine detail of new memories. Deaf individuals also performed better in a scene-discrimination test, which correlated positively with performance on the long-term memory test. Our findings provide evidence that deaf signers can demonstrate superior visual long-term memory, possibly because of enhanced visual attention during encoding. The relative contributions of factors including sign language fluency, protracted practice, and neural plasticity are still to be established. Our findings add to evidence showing that deaf signers are at an advantage in some respects, including the retention of detailed visual memories over the longer term.

Enhanced biological motion perception in deaf native signers

We conducted two studies to test how deaf signed language users perceive biological motions. We created 18 Biological Motion point-light displays (PLDs) depicting everyday human actions, and 18 Scrambled control PLDs. First, we conducted an online behavioral rating survey, in which deaf and hearing raters identified the biological motion PLDs and rated how easy it was for them to identify the actions. Then, we conducted an EEG study in which Deaf Signers and Hearing Non-Signers watched both the Biological Motion PLDs and the Scrambled PLDs, and we computed the time-frequency responses within the theta, alpha, and beta EEG rhythms. From the behavioral rating task, we show that the deaf raters reported significantly less effort required for identifying the Biological motion PLDs, across all stimuli. The EEG results showed that the Deaf Signers showed theta, mu, and beta differentiation between Scrambled and Biological PLDs earlier and more consistently than Hearing Non-Signers. We conclude that native ASL users exhibit experience-dependent neuroplasticity in the domain of biological human motion perception.