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Stimulus degradation adds to working memory load during speech processing.We investigated whether this applies to signprocessing and, if so, whether the mechanism implicates secondary auditory cortex.We conducted an fMRI experimentwhere 16 deaf early signers (DES) and 22 hearing non-signers performed a sign-based n-back task with three load levels andstimuli presented at high and low resolution.We found decreased behavioral performance with increasing load anddecreasing visual resolution, but the neurobiological mechanisms involved differed between the two manipulations and didso for both groups. Importantly, while the load manipulation was, as predicted, accompanied by activation in thefrontoparietal working memory network, the resolution manipulation resulted in temporal and occipital activation.Furthermore, we found evidence of cross-modal reorganization in the secondary auditory cortex: DES had strongeractivation and stronger connectivity between this and several other regions.We conclude that load and stimulus resolutionhave different neural underpinnings in the visual–verbal domain, which has consequences for current working memorymodels, and that for DES the secondary auditory cortex is involved in the binding of representations when task demandsare low. Funding; Swedish Research CouncilSwedish Research CouncilEuropean Commission [2015-00929]

The processing of a language involves a neural language network including temporal, parietal, and frontal cortical regions. This applies to spoken as well as signed languages. Previous research suggests that spoken language proficiency is associated with resting-state functional connectivity (rsFC) between language regions and other regions of the brain. Given the similarities in neural activation for spoken and signed languages, rsFC-behavior associations should also exist for sign language tasks. In this study, we explored the associations between rsFC and two types of linguistic skills in sign language: phonological processing skill and accuracy in elicited sentence production. Fifteen adult, deaf early signers were enrolled in a resting-state functional magnetic resonance imaging (fMRI) study. In addition to fMRI data, behavioral tests of sign language phonological processing and sentence reproduction were administered. Using seed-to-voxel connectivity analysis, we investigated associations between behavioral proficiency and rsFC from language-relevant nodes: bilateral inferior frontal gyrus (IFG) and posterior superior temporal gyrus (STG). Results showed that worse sentence processing skill was associated with stronger positive rsFC between the left IFG and left sensorimotor regions. Further, sign language phonological processing skill was associated with positive rsFC from right IFG to middle frontal gyrus/frontal pole although this association could possibly be explained by domain-general cognitive functions. Our findings suggest a possible connection between rsFC and developmental language outcomes in deaf individuals.

If the brain is deprived of input from one or more senses during development, functional and structural reorganization of the deprived regions takes place. However, little is known about how sensory deprivation affects large-scale brain networks. In the present study, we use data-driven independent component analysis (ICA) to characterize large-scale brain networks in 15 deaf early signers and 24 hearing non-signers based on resting-state functional MRI data. We found differences between the groups in independent components representing the left lateralized control network, the default network, the ventral somatomotor network, and the attention network. In addition, we showed stronger functional connectivity for deaf compared to hearing individuals from the middle and superior temporal cortices to the cingulate cortex, insular cortex, cuneus and precuneus, supramarginal gyrus, supplementary motor area, and cerebellum crus 1, and stronger connectivity for hearing non-signers to hippocampus, middle and superior frontal gyri, pre- and postcentral gyri, and cerebellum crus 8. These results show that deafness induces large-scale network reorganization, with the middle/superior temporal cortex as a central node of plasticity. Cross-modal reorganization may be associated with behavioral adaptations to the environment, including superior ability in some visual functions such as visual working memory and visual attention, in deaf signers.

Purpose The purpose of this study was to conceptualize the subtle balancing act between language input and prediction (cognitive priming of future input) to achieve understanding of communicated content. When understanding fails, reconstructive postdiction is initiated. Three memory systems play important roles: working memory (WM), episodic long-term memory (ELTM), and semantic long-term memory (SLTM). The axiom of the Ease of Language Understanding (ELU) model is that explicit WM resources are invoked by a mismatch between language input-in the form of rapid automatic multimodal binding of phonology-and multimodal phonological and lexical representations in SLTM. However, if there is a match between rapid automatic multimodal binding of phonology output and SLTM/ELTM representations, language processing continues rapidly and implicitly. Method and Results In our first ELU approach, we focused on experimental manipulations of signal processing in hearing aids and background noise to cause a mismatch with LTM representations; both resulted in increased dependence on WM. Our second-and main approach relevant for this review article-focuses on the relative effects of age-related hearing loss on the three memory systems. According to the ELU, WM is predicted to be frequently occupied with reconstruction of what was actually heard, resulting in a relative

The study of deafness and sign language has provided a means of dissociating modality specificity from higher level abstract processes in the brain. Differentiating these is fundamental for establi ...

The current update of the Ease of Language Understanding (ELU) model evaluates the predictive and postdictive aspects of speech understanding and communication.The aspects scrutinised concern: (1) Signal distortion and working memory capacity (WMC), (2) WMC and early attention mechanisms, (3) WMC and use of phonological and semantic information, (4) hearing loss, WMC and long-term memory (LTM), (5) WMC and effort, and (6) the ELU model and sign language. Study Samples: Relevant literature based on own or others' data was used.Expectations 1-4 are supported whereas 5-6 are constrained by conceptual issues and empirical data. Further strands of research were addressed, focussing on WMC and contextual use, and on WMC deployment in relation to hearing status. A wider discussion of task demands, concerning, for example, inference-making and priming, is also introduced and related to the overarching ELU functions of prediction and postdiction. Finally, some new concepts and models that have been inspired by the ELU-framework are presented and discussed.The ELU model has been productive in generating empirical predictions/expectations, the majority of which have been confirmed. Nevertheless, new insights and boundary conditions need to be experimentally tested to further shape the model.

Strengthening the connections between sign language and written language may improve reading skills in deaf and hard-of-hearing (DHH) signing children. The main aim of the present study was to investigate whether computerized sign language-based literacy training improves reading skills in DHH signing children who are learning to read. Further, longitudinal associations between sign language skills and developing reading skills were investigated. Participants were recruited from Swedish state special schools for DHH children, where pupils are taught in both sign language and spoken language. Reading skills were assessed at five occasions and the intervention was implemented in a cross-over design. Results indicated that reading skills improved over time and that development of word reading was predicted by the ability to imitate unfamiliar lexical signs, but there was only weak evidence that it was supported by the intervention. These results demonstrate for the first time a longitudinal link between sign-based abilities and word reading in DHH signing children who are learning to read. We suggest that the active construction of novel lexical forms may be a supramodal mechanism underlying word reading development.

The ability to keep information in mind for processing is known as working memory and is vital for learning. Children who have difficulty keeping up in school may have working memory limitations rather than limitations in the specific tasks they are assigned. In particular, children with functional impairments at the sensory or cognitive level may have difficulty performing tasks, either because the impairment hinders the development of the working memory system as such or because it hinders the development of linguistic and cognitive skills underpinning working memory development. Marshall et al. (2015) studied this issue by investigating working memory and its relation to language processing in two different groups of deaf children: native users of British Sign Language (BSL) and non-native BSL users, as well as in a control group of typically developing children with no hearing difficulties and no knowledge of sign language. The native signers had at least one deaf parent who had communicated in sign language with their child since birth. The non-native signers had acquired sign language later. All three groups performed two executively demanding non-verbal working memory tasks as well as an expressive vocabulary test and a narration task based on a filmed scenario enacted in BSL. Results showed that the non-native signers performed more poorly than the hearing participants on both working memory tasks while there was no difference in performance between the native signers and the hearing participants. The non-native signers had poorer vocabulary scores than the native signers who in turn had poorer vocabulary scores than the hearing children. However, there were no group differences on the narration task. Regression analysis showed that vocabulary was a significant unique predictor of performance on both of the working memory tasks. This association was all the more striking considering that there were no explicit demands on verbal skills in the working memory tasks. Marshall et al. (2015) argue that this pattern of results allows them to tease apart effects of auditory and language experience: while both of the deaf groups have experienced auditory deprivation, only one of them (non-native signers) has reduced language experience. In particular, the authors' interpretation is that while both auditory deprivation and reduced language experience have an impact on vocabulary development, reduced language experience, but not auditory deprivation as such, has an effect on the development of non-verbal working memory. The connection between language experience and development of working memory is of both practical and theoretical importance. The interplay of linguistic and cognitive skills during language understanding under adverse conditions is described by the Ease of Language Understanding model (ELU, Ronnberg et al., 2013). This model proposes that when adverse listening conditions such as hearing impairment or background noise give rise to mismatch between the incoming language signal and cognitive representations, engagement of explicit working memory mechanisms is triggered. Such explicit processing is associated with a cost in terms of the cognitive resources that have to be diverted from other activities, such as learning. The ELU model has proved to have explanatory power for adults, but until recently it has not been applied to development. In an experimental study conducted in Sweden (Holmer et al., 2016), imitation of manual gestures was elicited from deaf and hard-of-hearing (DHH) signing children and hearing non-signing children. The manual gestures used as stimuli belonged to three categories: lexical items in Swedish Sign Language (SSL, familiar to the DHH signing children but not the hearing children); lexical items in BSL (unfamiliar to both groups), and non-signs (phonotactically illegal and unfamiliar to both groups). Imitation of unfamiliar manual gestures can be compared to non-word repetition (Marshall, 2014), an established measure of working memory in the developmental literature (Gathercole, 2006). We hypothesized on the basis of the ELU model that pre-existing cognitive representations would allow the DHH signing children to imitate familiar signs more accurately than unfamiliar signs and that the performance of this group would be better than that of sign-naive hearing children. We found no difference between groups on initial testing, although both groups imitated lexical signs more accurately than non-signs. However, when imitation was elicited a second time, we found that the performance of DHH signing children improved more than that of hearing children across gesture categories. Further, the second set of imitation scores was predicted not only by domain general language skills for both groups but also by modality specific language skills. On the basis of these findings, we proposed that both domain general and language modality specific skills are brought into play during working memory processing and that this leads to the establishment of new cognitive representations as well as to redefinition of existing representations (Holmer et al., 2016). This proposed mechanism represents a developmental extension of the ELU model, D-ELU (Holmer et al., 2016), see Figure ​Figure11. Figure 1 The Developmental Ease of Language Understanding (D-ELU) model. RAMBPHO stands for Rapid, Automatic, Multimodal Binding of PHOnology and LTM stands for Long-Term Memory. When input cannot be matched to long-term representations in the RAMBPHO buffer, ... The results reported by Marshall et al. (2015) can be understood in terms of the D-ELU mechanism. Although congenital or early deafness may lead to impoverished speech input, development of domain general working memory in DHH children can be supported by ensuring that they are engaged from an early age in executively demanding linguistic activity in an appropriate language modality.

Theory of Mind (ToM) is related to reading comprehension in hearing children. In the present study, we investigated progression in ToM in Swedish deaf and hard-of-hearing (DHH) signing children who were learning to read, as well as its assocation with reading comprehension. Thirteen children at Swedish state primary schools for DHH children performed a Swedish Sign Language (SSL) version of the Wellman and Liu (2004) ToM scale, along with tests of reading comprehension, SSL comprehension, and working memory. Results indicated that ToM progression did not differ from that reported in previous studies, although ToM development was delayed despite age-appropriate sign language skills. Correlation analysis revealed that ToM was associated with reading comprehension and working memory, but not sign language comprehension. We propose that some factor not investigated in the present study, possibly represented by inference making constrained by working memory capacity, supports both ToM and reading comprehension and may thus explain the results observed in the present study. Funding agencies: Swedish Research Council for Health, Working Life and Welfare [2008-0846]

Reading development is supported by strong language skills, not least in deaf and hard-of-hearing (DHH) children. The work in the present thesis investigates reading development in DHH children who ...

This study explored the development of theory of mind (ToM) in 80 Swedish-speaking 3- to 5-year-olds, a previously unstudied language and culture. The ToM scale was translated and tested in a Swedi ...

Imitation and language processing are closely connected. According to the Ease of Language Understanding (ELU) model (Ronnberg et al., 2013) pre-existing mental representation of lexical items facilitates language understanding. Thus, imitation of manual gestures is likely to be enhanced by experience of sign language. We tested this by eliciting imitation of manual gestures from deaf and hard-of-hearing (DHH) signing and hearing non-signing children at a similar level of language and cognitive development. We predicted that the DHH signing children would be better at imitating gestures lexicalized in their own sign language (Swedish Sign Language, SSL) than unfamiliar British Sign Language (BSL) signs, and that both groups would be better at imitating lexical signs (SSL and BSL) than non-signs. We also predicted that the hearing non-signing children would perform worse than DHH signing children with all types of gestures the first time (T1) we elicited imitation, but that the performance gap between groups would be reduced when imitation was elicited a second time (T2). Finally, we predicted that imitation performance on both occasions would be associated with linguistic skills, especially in the manual modality. A split-plot repeated measures ANOVA demonstrated that DHH signers imitated manual gestures with greater precision than non-signing children when imitation was elicited the second but not the first time. Manual gestures were easier to imitate for both groups when they were lexicalized than when they were not; but there was no difference in performance between familiar and unfamiliar gestures. For both groups, language skills at T1 predicted imitation at T2. Specifically, for DHH children, word reading skills, comprehension and phonological awareness of sign language predicted imitation at T2. For the hearing participants, language comprehension predicted imitation at T2, even after the effects of working memory capacity and motor skills were taken into account. These results demonstrate that experience of sign language enhances the ability to imitate manual gestures once representations have been established, and suggest that the inherent motor patterns of lexical manual gestures are better suited for representation than those of non-signs. This set of findings prompts a developmental version of the ELU model, D-ELU. Funding Agencies|Swedish Research Council for Health, Working Life and Welfare [2008-0846]

The Ease of Language Understanding model (Ronnberg et al., 2013) predicts that decreasing the distinctness of language stimuli increases working memory load; in the speech domain this notion is supported by empirical evidence. Our aim was to determine whether such an over-additive interaction can be generalized to sign processing in sign-naive individuals and whether it is modulated by experience of computer gaming. Twenty young adults with no knowledge of sign language performed an n-back working memory task based on manual gestures lexicalized in sign language; the visual resolution of the signs and working memory load were manipulated. Performance was poorer when load was high and resolution was low. These two effects interacted over-additively, demonstrating that reducing the resolution of signed stimuli increases working memory load when there is no pre-existing semantic representation. This suggests that load and distinctness are handled by a shared amodal mechanism which can be revealed empirically when stimuli are degraded and load is high, even without pre-existing semantic representation. There was some evidence that the mechanism is influenced by computer gaming experience. Future work should explore how the shared mechanism is influenced by pre-existing semantic representation and sensory factors together with computer gaming experience. Funding Agencies|Linnaeus Centre HEAD grant from the Swedish Research Council

Similar working memory (WM) for lexical items has been demonstrated for signers and non-signers while short-term memory (STM) is regularly poorer in deaf than hearing individuals. In the present study, we investigated digit-based WM and STM in Swedish and British deaf signers and hearing non-signers. To maintain good experimental control we used printed stimuli throughout and held response mode constant across groups. We showed that deaf signers have similar digit-based WM performance, despite shorter digit spans, compared to well-matched hearing non-signers. We found no difference between signers and non-signers on STM span for letters chosen to minimize phonological similarity or in the effects of recall direction. This set of findings indicates that similar WM for signers and non-signers can be generalized from lexical items to digits and suggests that poorer STM in deaf signers compared to hearing non-signers may be due to differences in phonological similarity across the language modalities of sign and speech.