| 1. |
- Andin, Josefine, 1979-, et al.
(author)
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Similar digit-based working memory in deaf signers and hearing non-signers despite digit span differences
- 2013
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In: Frontiers in Psychology. - : Frontiers Media SA. - 1664-1078. ; 4:942
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Journal article (peer-reviewed)abstract
- 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.
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| 2. |
- Cardin, Velia, et al.
(author)
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Differential activity in Heschl's gyrus between deaf and hearing individuals is due to auditory deprivation rather than language modality
- 2016
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In: NeuroImage. - : Elsevier BV. - 1053-8119 .- 1095-9572. ; 124, s. 96-106
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Journal article (peer-reviewed)abstract
- Sensory cortices undergo crossmodal reorganisation as a consequence of sensory deprivation. Congenital deafness in humans represents a particular case with respect to other types of sensory deprivation, because cortical reorganisation is not only a consequence of auditory deprivation, but also of language-driven mechanisms. Visual crossmodal plasticity has been found in secondary auditory cortices of deaf individuals, but it is still unclear if reorganisation also takes place in primary auditory areas, and how this relates to language modality and auditory deprivation.Here, we dissociated the effects of language modality and auditory deprivation on crossmodal plasticity in Heschl's gyrus as a whole, and in cytoarchitectonic region Te1.0 (likely to contain the core auditory cortex). Using fMRI, we measured the BOLD response to viewing sign language in congenitally or early deaf individuals with and without sign language knowledge, and in hearing controls.Results show that differences between hearing and deaf individuals are due to a reduction in activation caused by visual stimulation in the hearing group, which is more significant in Te1.0 than in Heschl's gyrus as a whole. Furthermore, differences between deaf and hearing groups are due to auditory deprivation, and there is no evidence that the modality of language used by deaf individuals contributes to crossmodal plasticity in Heschl's gyrus.
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| 3. |
- Cardin, Velia, et al.
(author)
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Dissociating cognitive and sensory neural plasticity in human superior temporal cortex
- 2013
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In: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 4:2
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Journal article (peer-reviewed)abstract
- Disentangling the effects of sensory and cognitive factors on neural reorganization is fundamental for establishing the relationship between plasticity and functional specialization. Auditory deprivation in humans provides a unique insight into this problem, because the origin of the anatomical and functional changes observed in deaf individuals is not only sensory, but also cognitive, owing to the implementation of visual communication strategies such as sign language and speechreading. Here, we describe a functional magnetic resonance imaging study of individuals with different auditory deprivation and sign language experience. We find that sensory and cognitive experience cause plasticity in anatomically and functionally distinguishable substrates. This suggests that after plastic reorganization, cortical regions adapt to process a different type of input signal, but preserve the nature of the computation they perform, both at a sensory and cognitive level.
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| 4. |
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| 5. |
- Rudner, Mary, et al.
(author)
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Neural Networks Supporting Phoneme Monitoring Are Modulated by Phonology but Not Lexicality or Iconicity: Evidence From British and Swedish Sign Language
- 2019
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In: Frontiers in Human Neuroscience. - : FRONTIERS MEDIA SA. - 1662-5161. ; 13
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Journal article (peer-reviewed)abstract
- 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.
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| 6. |
- Rudner, Mary, 1958-, et al.
(author)
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Neural substrates of sign language processing differ partially between Swedish and British signers
- 2013
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Conference paper (other academic/artistic)abstract
- The lexicons of British Sign Language (BSL) and Swedish Sign Language (SSL) only partially overlap. This offers the opportunity of studying the neurocognitive systems that support the processing of familiar and non-familiar lexical signs as well as non-signs under controlled conditions. In particular, effects relating either to a particular sign language or to the users of a particular sign language can be identified. Fifteen deaf native users of BSL and fifteen deaf native users of SSL took part in an fMRI study. All were right-handed and neurologically healthy. The two groups were matched on age, gender, level of education and non-verbal intelligence. In the scanner participants were presented with video recorded sign-based material that consisted of 1) BSL: signs lexicalized in BSL but not SSL, 2) SSL: signs lexicalized in SSL but not BSL, 3) Cognates: signs lexicalized in both BSL and SSL, 4) Non-signs made up of handshapes, movements, locations and orientations put together in a phonotactically illegal manner. The recordings were modeled by a deaf native signer of a third sign language (German Sign Language) to avoid bias to BSL or SSL. All stimuli were matched for complexity. Stimulus types 1, 2 and 3 were matched for familiarity and age of acquisition. Stimulus types 1 and 2 were matched for iconicity. Participants performed two tasks in the scanner. Both tasks involved monitoring stimuli for specific phonological components according to a cue presented before each block of 12 stimuli. One task involved monitoring for handshape and the other task involved monitoring for location. Whole brain analysis of the fMRI data revealed more activation for non-signs than unfamiliar signs (SSL for British signers and BSL for Swedish signers) in superior posterior parietal regions bilaterally across tasks. No differences in activation could be attributed to semantic content (familiar versus unfamiliar signs) or iconicity (cognates versus familiar signs). Interestingly, there was more activation in British compared to Swedish signers across conditions in a region anterior to the left cytoarchitectonic definition of area V5/MT+ (Malikovic et al., 2007) and right middle occipital gyrus. There were no interactions between group and either task or type of material. This pattern of results shows that the neural substrates of sign language processing partially differ between Swedish and British signers. This difference cannot be attributed to differences in processing the phonological parameters of handshape and location or to differences in processing semantics and iconicity. One possible explanation is a difference in reliance on non-manual components of sign language in British and Swedish signers.
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| 7. |
- Rudner, Mary, et al.
(author)
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Preexisting semantic representation improves working memory performance in the visuospatial domain
- 2016
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In: Memory & Cognition. - : Springer. - 0090-502X .- 1532-5946. ; 44:4, s. 608-620
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Journal article (peer-reviewed)abstract
- 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.
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| 8. |
- Rudner, Mary, 1958-, et al.
(author)
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Reading ability in adult deaf native signers is positively associated with their ability to judge the grammatically of their native sign language
- 2012
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Conference paper (other academic/artistic)abstract
- For deaf native sign language users, learning to read means acquiring a second language. With limited access to the phonology of spoken language, it is difficult to establish the connection to orthography, which is a key to reading for hearing individuals. For hearing individuals, reading ability is often associated with working memory capacity (WMC) and phonological processing abilities (PPA). However, this association is not as clear-cut for deaf individuals, whose reading ability is usually poorer and who may have a different route to reading. In the present study we compared English reading skill (Vernon-Warden Reading Comprehension Test Revised, 1996) in adult deaf native users of British Sign Language (BSL, n=24) with hearing, non-signing native English speakers (n=24) matched for age and non-verbal intelligence. We also explored the association between reading level, PPA and WMC in both groups and between reading level and performance on the BSL Grammaticality Judgement Task (BSLGJT; Cormier et al., 2012) in deaf signers. Consistent with previous findings, the average reading level was lower for deaf signers than for hearing non-signers (mean reading age: 16 years vs. adult, respectively) and, for hearing non-signers, reading level was positively associated with WMC and PPA. In contrast, for deaf signers, we found no association between reading skill and WMC, English PPA or BSL PPA; instead, reading level was positively associated with BSLGJT performance. These novel findings suggest that, in deaf native signers, higher level sign language skills, such as grammatical knowledge, may provide a route to reading.
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