Executive Function in Deaf Native Signing Children.

The aim of this study is twofold: To examine if deafness is invariably associated with deficits in executive function (EF) and to investigate the relationship between sign language proficiency and EF in deaf children of deaf parents with early exposure to a sign language. It is also the first study of EF in children acquiring Polish Sign Language. Even though the mothers of the deaf children (N = 20) had lower levels of education compared with the mothers of a hearing control group, the children performed similarly to their hearing peers (N = 20) on a variety of EF task-based assessments. Only in the Go/No-go task were weaker inhibition skills observed in younger deaf children (6-9 years) compared with hearing peers, and this difference was not seen in older children (10-12 years). Hence, deafness does not necessarily impair EF; however, attentional and inhibition abilities may be acquired via a different route in deaf children. Sign language receptive skills predicted EF in deaf children. In conclusion, we highlight the importance of deaf parenting building the scaffolding for EF in deaf children.

Resting-state functional connectivity in deaf and hearing individuals and its link to executive processing.

Sensory experience shapes brain structure and function, and it is likely to influence the organisation of functional networks of the brain, including those involved in cognitive processing. Here we investigated the influence of early deafness on the organisation of resting-state networks of the brain and its relation to executive processing. We compared resting-state connectivity between deaf and hearing individuals across 18 functional networks and 400 ROIs. Our results showed significant group differences in connectivity between seeds of the auditory network and most large-scale networks of the brain, in particular the somatomotor and salience/ventral attention networks. When we investigated group differences in resting-state fMRI and their link to behavioural performance in executive function tasks (working memory, inhibition and switching), differences between groups were found in the connectivity of association networks of the brain, such as the salience/ventral attention and default-mode networks. These findings indicate that sensory experience influences not only the organisation of sensory networks, but that it also has a measurable impact on the organisation of association networks supporting cognitive processing. Overall, our findings suggest that different developmental pathways and functional organisation can support executive processing in the adult brain.

Deaf Language Specialists: Delivering Language Therapy in Signed Languages.

Deaf professionals, whom we term Deaf Language Specialists (DLS), are frequently employed to work with children and young people who have difficulties learning sign language, but there are few accounts of this work in the literature. Through questionnaires and focus groups, 23 DLSs described their work in this area. Deductive thematic analysis was used to identify how this compared to the work of professionals (typically Speech and Language Therapists/Pathologists, SLPs) working with hearing children with difficulties learning spoken language. Inductive thematic analysis resulted in the identification of two additional themes: while many practices by DLSs are similar to those of SLPs working with hearing children, a lack of training, information, and resources hampers their work; additionally, the cultural context of language and deafness makes this a complex and demanding area of work. These findings add to the limited literature on providing language interventions in the signed modality with clinical implications for meeting the needs of deaf and hard-of-hearing children who do not achieve expectations of learning a first language in their early years. The use of these initial results in two further study phases to co-deliver interventions and co-produce training for DLSs is briefly described.

Sensory experience modulates the reorganization of auditory regions for executive processing.

Crossmodal plasticity refers to the reorganization of sensory cortices in the absence of their typical main sensory input. Understanding this phenomenon provides insights into brain function and its potential for change and enhancement. Using functional MRI, we investigated how early deafness influences crossmodal plasticity and the organization of executive functions in the adult human brain. Deaf (n = 25; age: mean = 41.68, range = 19-66, SD = 14.38; 16 female, 9 male) and hearing (n = 20; age: mean = 37.50, range = 18-66, SD = 16.85; 15 female, 5 male) participants performed four visual tasks tapping into different components of executive processing: task switching, working memory, planning and inhibition. Our results show that deaf individuals specifically recruit 'auditory' regions during task switching. Neural activity in superior temporal regions, most significantly in the right hemisphere, are good predictors of behavioural performance during task switching in the group of deaf individuals, highlighting the functional relevance of the observed cortical reorganization. Our results show executive processing in typically sensory regions, suggesting that the development and ultimate role of brain regions are influenced by perceptual environmental experience.

The effect of dopamine on the comprehension of spectrally-shifted noise-vocoded speech: a pilot study.

Objectives: Cochlear implantation has proven beneficial in restoring hearing. However, success is variable, and there is a need for a simple post-implantation therapy that could significantly increase implantation success. Dopamine has a general role in learning and in assigning value to environmental stimuli. We tested the effect of dopamine in the comprehension of spectrally-shifted noise-vocoded (SSNV) speech, which simulates, in hearing individuals, the signal delivered by a cochlear implant (CI).Design and study sample: Thirty-five participants (age = 38.0 ± 10.1 SD) recruited from the general population were divided into three groups. We tested SSNV speech comprehension in two experimental sessions. In one session, a metabolic precursor of dopamine (L-DOPA) was administered to participants in two of the groups; a placebo was administered in the other session.Results: A single dose of L-DOPA interacted with training to improve perception of SSNV speech, but did not significantly accelerate learning.Conclusions: These findings are a first step in exploring the use of dopamine to enhance speech understanding in CI patients. Replications of these results using SSNV in individuals with normal hearing, and also in CI users, are needed to determine whether these effects can translate into benefits in everyday language comprehension.

Neural Networks Supporting Phoneme Monitoring Are Modulated by Phonology but Not Lexicality or Iconicity: Evidence From British and Swedish Sign Language.

Sign languages are natural languages in the visual domain. Because they lack a written form, they provide a sharper tool than spoken languages for investigating lexicality effects which may be confounded by orthographic processing. In a previous study, we showed that the neural networks supporting phoneme monitoring in deaf British Sign Language (BSL) users are modulated by phonology but not lexicality or iconicity. In the present study, we investigated whether this pattern generalizes to deaf Swedish Sign Language (SSL) users. British and SSLs have a largely overlapping phoneme inventory but are mutually unintelligible because lexical overlap is small. This is important because it means that even when signs lexicalized in BSL are unintelligible to users of SSL they are usually still phonologically acceptable. During fMRI scanning, deaf users of the two different sign languages monitored signs that were lexicalized in either one or both of those languages for phonologically contrastive elements. Neural activation patterns relating to different linguistic levels of processing were similar across SLs; in particular, we found no effect of lexicality, supporting the notion that apparent lexicality effects on sublexical processing of speech may be driven by orthographic strategies. As expected, we found an effect of phonology but not iconicity. Further, there was a difference in neural activation between the two groups in a motion-processing region of the left occipital cortex, possibly driven by cultural differences, such as education. Importantly, this difference was not modulated by the linguistic characteristics of the material, underscoring the robustness of the neural activation patterns relating to different linguistic levels of processing.

Evaluation of different chrominance models in the detection and reconstruction of faces and hands using the growing neural gas network.

Physical traits such as the shape of the hand and face can be used for human recognition and identification in video surveillance systems and in biometric authentication smart card systems, as well as in personal health care. However, the accuracy of such systems suffers from illumination changes, unpredictability, and variability in appearance (e.g. occluded faces or hands, cluttered backgrounds, etc.). This work evaluates different statistical and chrominance models in different environments with increasingly cluttered backgrounds where changes in lighting are common and with no occlusions applied, in order to get a reliable neural network reconstruction of faces and hands, without taking into account the structural and temporal kinematics of the hands. First a statistical model is used for skin colour segmentation to roughly locate hands and faces. Then a neural network is used to reconstruct in 3D the hands and faces. For the filtering and the reconstruction we have used the growing neural gas algorithm which can preserve the topology of an object without restarting the learning process. Experiments conducted on our own database but also on four benchmark databases (Stirling's, Alicante, Essex, and Stegmann's) and on deaf individuals from normal 2D videos are freely available on the BSL signbank dataset. Results demonstrate the validity of our system to solve problems of face and hand segmentation and reconstruction under different environmental conditions.

Cerebral lateralisation during signed and spoken language production in children born deaf.

The effect of sensory experience on hemispheric specialisation for language production is not well understood. Children born deaf, including those who have cochlear implants, have drastically different perceptual experiences of language than their hearing peers. Using functional transcranial Doppler sonography (fTCD), we measured lateralisation during language production in a heterogeneous group of 19 deaf children and in 19 hearing children, matched on language ability. In children born deaf, we observed significant left lateralisation during language production (British Sign Language, spoken English, or a combination of languages). There was no difference in the strength of lateralisation between deaf and hearing groups. Comparable proportions of children were categorised as left-, right-, or not significantly-lateralised in each group. Moreover, an exploratory subgroup analysis showed no significant difference in lateralisation between deaf children with cochlear implants and those without. These data suggest that the processes underpinning language production remain robustly left lateralised regardless of sensory language experience.

Real Time Hand Movement Trajectory Tracking for Enhancing Dementia Screening in Ageing Deaf Signers of British Sign Language.

Real time hand movement trajectory tracking based on machine learning approaches may assist the early identification of dementia in ageing Deaf individuals who are users of British Sign Language (BSL), since there are few clinicians with appropriate communication skills, and a shortage of sign language interpreters. Unlike other computer vision systems used in dementia stage assessment such as RGBD video with the aid of depth camera, activities of daily living (ADL) monitored by information and communication technologies (ICT) facilities, or X-Ray, computed tomography (CT), and magnetic resonance imaging (MRI) images fed to machine learning algorithms, the system developed here focuses on analysing the sign language space envelope (sign trajectories/depth/speed) and facial expression of deaf individuals, using normal 2D videos. In this work, we are interested in providing a more accurate segmentation of objects of interest in relation to the background, so that accurate real-time hand trajectories (path of the trajectory and speed) can be achieved. The paper presents and evaluates two types of hand movement trajectory models. In the first model, the hand sign trajectory is tracked by implementing skin colour segmentation. In the second model, the hand sign trajectory is tracked using Part Affinity Fields based on the OpenPose Skeleton Model [1, 2]. Comparisons of results between the two different models demonstrate that the second model provides enhanced improvements in terms of tracking accuracy and robustness of tracking. The pattern differences in facial and trajectory motion data achieved from the presented models will be beneficial not only for screening of deaf individuals for dementia, but also for assessment of other acquired neurological impairments associated with motor changes, for example, stroke and Parkinson's disease.

Atypical maternal cradling laterality in an impoverished South African population.

Human studies consistently report a 60%-80% maternal left cradling preference. The dominant explanation points to an engagement of the emotionally more-attuned right brain. In contrast, we found equal incidences of left (31.3%), right (34.3%) and no-preference (34.3%) cradling in an impoverished South African population living under adverse conditions characterized by extreme dangers. We found striking differences on the Parenting Stress Index (PSI) between mothers with no cradling laterality preference and mothers with either a left or right preference. In several mammals a homologous left preference becomes stronger when acute threats prevail, rendering the rightwards shift we observed under dangerous conditions seemingly paradoxical. We propose this paradox can be resolved in terms of life-history strategy theory which predicts reduced parental investment in chronically dangerous environments. We interpret our high PSI score findings in no-preference cradlers as indicative of poorer, or at least ambivalent, maternal coping which many studies show is typically associated with reduced emotional sensitivity and responsiveness. We suggest that the latter may be a psychological mechanism mediating a partial withdrawal of parental investment in response to an enduringly adverse environment. To the best of our knowledge, this is the first study investigating cradling laterality preferences in an adverse socioeconomic environment.

Differential coding of perception in the world's languages.

Is there a universal hierarchy of the senses, such that some senses (e.g., vision) are more accessible to consciousness and linguistic description than others (e.g., smell)? The long-standing presumption in Western thought has been that vision and audition are more objective than the other senses, serving as the basis of knowledge and understanding, whereas touch, taste, and smell are crude and of little value. This predicts that humans ought to be better at communicating about sight and hearing than the other senses, and decades of work based on English and related languages certainly suggests this is true. However, how well does this reflect the diversity of languages and communities worldwide? To test whether there is a universal hierarchy of the senses, stimuli from the five basic senses were used to elicit descriptions in 20 diverse languages, including 3 unrelated sign languages. We found that languages differ fundamentally in which sensory domains they linguistically code systematically, and how they do so. The tendency for better coding in some domains can be explained in part by cultural preoccupations. Although languages seem free to elaborate specific sensory domains, some general tendencies emerge: for example, with some exceptions, smell is poorly coded. The surprise is that, despite the gradual phylogenetic accumulation of the senses, and the imbalances in the neural tissue dedicated to them, no single hierarchy of the senses imposes itself upon language.

The impact of text segmentation on subtitle reading.

Understanding the way people watch subtitled films has become a central concern for subtitling researchers in recent years. Both subtitling scholars and professionals generally believe that in order to reduce cognitive load and enhance readability, line breaks in twoline subtitles should follow syntactic units. However, previous research has been inconclusive as to whether syntactic-based segmentation facilitates comprehension and reduces cognitive load. In this study, we assessed the impact of text segmentation on subtitle processing among different groups of viewers: hearing people with different mother tongues (English, Polish, and Spanish) and deaf, hard of hearing, and hearing people with English as a first language. We measured three indicators of cognitive load (difficulty, effort, and frustration) as well as comprehension and eye tracking variables. Participants watched two video excerpts with syntactically and non-syntactically segmented subtitles. The aim was to determine whether syntactic-based text segmentation as well as the viewers' linguistic background influence subtitle processing. Our findings show that non-syntactically segmented subtitles induced higher cognitive load, but they did not adversely affect comprehension. The results are discussed in the context of cognitive load, audiovisual translation, and deafness.

The Organization of Working Memory Networks is Shaped by Early Sensory Experience.

Early deafness results in crossmodal reorganization of the superior temporal cortex (STC). Here, we investigated the effect of deafness on cognitive processing. Specifically, we studied the reorganization, due to deafness and sign language (SL) knowledge, of linguistic and nonlinguistic visual working memory (WM). We conducted an fMRI experiment in groups that differed in their hearing status and SL knowledge: deaf native signers, and hearing native signers, hearing nonsigners. Participants performed a 2-back WM task and a control task. Stimuli were signs from British Sign Language (BSL) or moving nonsense objects in the form of point-light displays. We found characteristic WM activations in fronto-parietal regions in all groups. However, deaf participants also recruited bilateral posterior STC during the WM task, independently of the linguistic content of the stimuli, and showed less activation in fronto-parietal regions. Resting-state connectivity analysis showed increased connectivity between frontal regions and STC in deaf compared to hearing individuals. WM for signs did not elicit differential activations, suggesting that SL WM does not rely on modality-specific linguistic processing. These findings suggest that WM networks are reorganized due to early deafness, and that the organization of cognitive networks is shaped by the nature of the sensory inputs available during development.

Assessing language skills in adult key word signers with intellectual disabilities: Insights from sign linguistics.

Manual signing is one of the most widely used approaches to support the communication and language skills of children and adults who have intellectual or developmental disabilities, and problems with communication in spoken language. A recent series of papers reporting findings from this population raises critical issues for professionals in the assessment of multimodal language skills of key word signers. Approaches to assessment will differ depending on whether key word signing (KWS) is viewed as discrete from, or related to, natural sign languages. Two available assessments from these different perspectives are compared. Procedures appropriate to the assessment of sign language production are recommended as a valuable addition to the clinician's toolkit. Sign and speech need to be viewed as multimodal, complementary communicative endeavours, rather than as polarities. Whilst narrative has been shown to be a fruitful context for eliciting language samples, assessments for adult users should be designed to suit the strengths, needs and values of adult signers with intellectual disabilities, using materials that are compatible with their life course stage rather than those designed for young children.

Sign, language, and gesture in the brain: Some comments.

In contrast with two widely held and contradictory views - that sign languages of deaf people are "just gestures," or that sign languages are "just like spoken languages" - the view from sign linguistics and developmental research in cognition presented by Goldin-Meadow & Brentari (G-M&B) indicates a more complex picture. We propose that neuroscience research suggests that a similar approach needs to be taken and offer some examples from research on the brain bases of sign language perception.

Synesthesia for manual alphabet letters and numeral signs in second-language users of signed languages.

Many synesthetes experience colors when viewing letters or digits. We document, for the first time, an analogous phenomenon among users of signed languages who showed color synesthesia for fingerspelled letters and signed numerals. Four synesthetes experienced colors when they viewed manual letters and numerals (in two cases, colors were subjectively projected on to the hands). There was a correspondence between the colors experienced for written graphemes and their manual counterparts, suggesting that the development of these two types of synesthesia is interdependent despite the fact that these systems are superficially distinct and rely on different perceptual recognition mechanisms in the brain.

Detecting Memory Impairment in Deaf People: A New Test of Verbal Learning and Memory in British Sign Language.

OBJECTIVE: Most existing tests of memory and verbal learning in adults were created for spoken languages, and are unsuitable for assessing deaf people who rely on signed languages. In response to this need for sign language measures, the British Sign Language Verbal Learning and Memory Test (BSL-VLMT) was developed. It follows the format of the English language Hopkins Verbal Learning Test Revised, using standardized video-presentation with novel stimuli and instructions wholly in British Sign Language, and no English language requirement. METHOD: Data were collected from 223 cognitively healthy deaf signers aged 50-89 and 12 deaf patients diagnosed with dementia. Normative data percentiles were derived for clinical use, and receiver-operating characteristic curves computed to explore the clinical potential and diagnostic sensitivity and specificity. RESULTS: The test showed good discrimination between the normative and clinical samples, providing preliminary evidence of clinical utility for identifying learning and memory impairment in older deaf signers with neurodegeneration. CONCLUSIONS: This innovative video testing approach transforms the ability to accurately detect memory impairments in deaf people and avoids the problems of using interpreters, with international potential for adapting similar tests into other signed languages.

Preexisting semantic representation improves working memory performance in the visuospatial domain.

Working memory (WM) for spoken language improves when the to-be-remembered items correspond to preexisting representations in long-term memory. We investigated whether this effect generalizes to the visuospatial domain by administering a visual n-back WM task to deaf signers and hearing signers, as well as to hearing nonsigners. Four different kinds of stimuli were presented: British Sign Language (BSL; familiar to the signers), Swedish Sign Language (SSL; unfamiliar), nonsigns, and nonlinguistic manual actions. The hearing signers performed better with BSL than with SSL, demonstrating a facilitatory effect of preexisting semantic representation. The deaf signers also performed better with BSL than with SSL, but only when WM load was high. No effect of preexisting phonological representation was detected. The deaf signers performed better than the hearing nonsigners with all sign-based materials, but this effect did not generalize to nonlinguistic manual actions. We argue that deaf signers, who are highly reliant on visual information for communication, develop expertise in processing sign-based items, even when those items do not have preexisting semantic or phonological representations. Preexisting semantic representation, however, enhances the quality of the gesture-based representations temporarily maintained in WM by this group, thereby releasing WM resources to deal with increased load. Hearing signers, on the other hand, may make strategic use of their speech-based representations for mnemonic purposes. The overall pattern of results is in line with flexible-resource models of WM.