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- Andin, Josefine, et al.
(författare)
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Deaf signers and hearing non-signers recruit similar networks for arithmetic and phonological tasks
- 2013
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Profoundly deaf individuals sometimes have difficulty with arithmetic and phonological tasks. In the present study we investigate if these differences can be attributed to differences in recruitment of neurobiological networks. Seventeen hearing non-signers (HN) and sixteen deaf signers (DS) matched on age, gender and non-verbal intelligence took part in an fMRI study. In the scanner three digit/letter pairs were visually presented and the participants performed six different blocked tasks tapping processing of digit and letter order, multiplication, subtraction and phonological ability. Data were analysed using two 2x2x2 ANOVAs; process (arithmetic, language) x level (high, low) x group (DS, HN). A main effect of process revealed language networks in the left inferior frontal gryus, supramarginal gyrus, fusiform gyrus and insula. Arithmetic networks included left middle orbital gyrus and superior medial gyrus. A main effect of level revealed low level processing (digit/letter order) in the right middle occipital gyrus and the right precuneus and high level processing (subtraction/multiplication/phonological ability) in left inferior frontal gyrus. There was no main effect of group but a significant task x group interaction in the right temporal pole which in DS (but not HN) was activated more for arithmetic than language processing (pfwe = .022) when multiplication was included in the analysis. This region is implicated in conceptual representation. These results suggest that both arithmetic and language are processed similarly by DS and HN with possible between-group differences in the use of conceptual representation in arithmetic and language tasks.
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- Andin, Josefine, et al.
(författare)
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Deaf signers use magnitude manipulatioin strategies for mulitplication : fMRI evidence
- 2014
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Evidence suggests that the lag reported in mathematics for deaf signers derives from difficulties related to the verbal system of number processing as described in the triple code model. For hearing individuals the verbal system has been shown to be recruited for both arithmetic and language tasks. In the present study we investigate for the first time neuronal representations of arithmetic in deaf signers. We examine if the neural network supporting arithmetic and language, including the horizontal portion of the intraparietal sulcus (HIPS), the superior parietal lobule (SPL) bilaterally, the left angular gyrus (AG), pars opercularis (POPE) and pars triangularis (PTRI) of the left inferior frontal gyrus (IFG), is differently recruited for deaf and hearing individuals. Imaging data were collected from 16 deaf signers and 16 well-matched hearing nonsigners, using the same stimulus material for all tasks, but with different cues. During multiplication, deaf signers recruited rHIPS more than hearing non-signers, suggesting greater involvement of magnitude manipulation processes related to the quantity system, whereas there was no evidence that the verbal system was recruited. Further, there was no support for the notion of a common representation of phonology for sign and speech as previously suggested.
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- Andin, Josefine, et al.
(författare)
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Deaf signers use phonology to do arithmetic
- 2014
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Ingår i: Learning and individual differences. - : Elsevier. - 1041-6080 .- 1873-3425. ; 32, s. 246-253
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Tidskriftsartikel (refereegranskat)abstract
- Deaf students generally lag several years behind hearing peers in arithmetic, but little is known about the mechanisms behind this. In the present study we investigated how phonological skills interact with arithmetic. Eighteen deaf signers and eighteen hearing non-signers took part in an experiment that manipulated arithmetic and phonological knowledge in the language modalities of sign and speech. Independent tests of alphabetical and native language phonological skills were also administered. There was no difference in performance between groups on subtraction, but hearing non-signers performed better than deaf signers on multiplication. For the deaf signers but not the hearing non-signers, multiplicative reasoning was associated with both alphabetical and phonological skills. This indicates that deaf signing adults rely on language processes to solve multiplication tasks, possibly because automatization of multiplication is less well established in deaf adults.
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- Andin, Josefine
(författare)
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Dealing with Digits : Arithmetic, Memory and Phonology in Deaf Signers
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Deafness has been associated with poor abilities to deal with digits in the context of arithmetic and memory, and language modality-specific differences in the phonological similarity of digits have been shown to influence short-term memory (STM). Therefore, the overall aim of the present thesis was to find out whether language modality-specific differences in phonological processing between sign and speech can explain why deaf signers perform at lower levels than hearing peers when dealing with digits. To explore this aim, the role of phonological processing in digit-based arithmetic and memory tasks was investigated, using both behavioural and neuroimaging methods, in adult deaf signers and hearing non-signers, carefully matched on age, sex, education and non-verbal intelligence. To make task demands as equal as possible for both groups, and to control for material effects, arithmetic, phonological processing, STM and working memory (WM) were all assessed using the same presentation and response mode for both groups. The results suggested that in digit-based STM, phonological similarity of manual numerals causes deaf signers to perform more poorly than hearing non-signers. However, for digit-based WM there was no difference between the groups, possibly due to differences in allocation of resources during WM. This indicates that similar WM for the two groups can be generalized from lexical items to digits. Further, we found that in the present work deaf signers performed better than expected and on a par with hearing peers on all arithmetic tasks, except for multiplication, possibly because the groups studied here were very carefully matched. However, the neural networks recruited for arithmetic and phonology differed between groups. During multiplication tasks, deaf signers showed an increased reliance on cortex of the right parietal lobe complemented by the left inferior frontal gyrus. In contrast, hearing non-signers relied on cortex of the left frontal and parietal lobes during multiplication. This suggests that while hearing non-signers recruit phonology-dependent arithmetic fact retrieval processes for multiplication, deaf signers recruit non-verbal magnitude manipulation processes. For phonology, the hearing non-signers engaged left lateralized frontal and parietal areas within the classical perisylvian language network. In deaf signers, however, phonological processing was limited to cortex of the left occipital lobe, suggesting that sign-based phonological processing does not necessarily activate the classical language network. In conclusion, the findings of the present thesis suggest that language modality-specific differences between sign and speech in different ways can explain why deaf signers perform at lower levels than hearing non-signers on tasks that include dealing with digits.
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