1,097 research outputs found

    Block design performance in the Williams syndrome phenotype: A problem with mental imagery?

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    Williams syndrome (WS) is a rare genetic disorder which, among other characteristics, has a distinctive cognitive profile. Non-verbal abilities are generally poor in relation to verbal abilities, but also show varying levels of ability in relation to each other. Performance on block construction tasks represents arguably the weakest non-verbal ability in WS. In this study we examined two requirements of block construction tasks in 21 individuals with WS and 21 typically developing (TD) control individuals. The Squares task, a novel two-dimensional block construction task, manipulated patterns by segmentation and perceptual cohesiveness to investigate the first factor, processing preference (local or global), and by obliqueness to examine the second factor, the ability to use mental imagery. These two factors were investigated directly by the Children?s Embedded Figures Test (CEFT; Witkin, Oltman, Raskin & Karp, 1971) and a mental rotation task respectively. Results showed that individuals with WS did not differ from the TD group in their processing style. However, the ability to use mental imagery was significantly poorer in the WS group than the TD group. This suggests that weak performance on the block construction tasks in WS may relate to an inability to use mental imagery

    Divided attention, selective attention and drawing: Processing preferences in Williams syndrome are dependent on the task administered

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    The visuo-spatial abilities of individuals with Williams syndrome (WS) have consistently been shown to be generally weak. These poor visuo-spatial abilities have been ascribed to a local processing bias by some [30] and conversely, to a global processing bias by others [24]. In this study, two identification versions and one drawing version of the Navon hierarchical processing task, a non-verbal task, were employed to investigate this apparent contradiction. The two identification tasks were administered to 21 individuals with WS, 21 typically developing individuals, matched by non-verbal ability, and 21 adult participants matched to the WS group by mean chronological age. The third, drawing task was administered to the WS group and the TD controls only. It was hypothesised that the WS group would show differential processing biases depending on the type of processing the task was measuring. Results from two identification versions of the Navon task measuring divided and selective attention showed that the WS group experienced equal interference from global to local as from local to global levels, and did not show an advantage of one level over another. This pattern of performance was broadly comparable to that of the control groups. The third task, a drawing version of the Navon task, revealed that individuals with WS were significantly better at drawing the local form in comparison to the global figure, whereas the typically developing control group did not show a bias towards either level. In summary, this study demonstrates that individuals with WS do not have a local or a global processing bias when asked to identify stimuli, but do show a local bias in their drawing abilities. This contrast may explain the apparently contrasting findings from previous studies

    Linking working memory and long-term memory: A computational model of the learning of new words

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    The nonword repetition (NWR) test has been shown to be a good predictor of children’s vocabulary size. NWR performance has been explained using phonological working memory, which is seen as a critical component in the learning of new words. However, no detailed specification of the link between phonological working memory and long-term memory (LTM) has been proposed. In this paper, we present a computational model of children’s vocabulary acquisition (EPAM-VOC) that specifies how phonological working memory and LTM interact. The model learns phoneme sequences, which are stored in LTM and mediate how much information can be held in working memory. The model’s behaviour is compared with that of children in a new study of NWR, conducted in order to ensure the same nonword stimuli and methodology across ages. EPAM-VOC shows a pattern of results similar to that of children: performance is better for shorter nonwords and for wordlike nonwords, and performance improves with age. EPAM-VOC also simulates the superior performance for single consonant nonwords over clustered consonant nonwords found in previous NWR studies. EPAM-VOC provides a simple and elegant computational account of some of the key processes involved in the learning of new words: it specifies how phonological working memory and LTM interact; makes testable predictions; and suggests that developmental changes in NWR performance may reflect differences in the amount of information that has been encoded in LTM rather than developmental changes in working memory capacity. Keywords: EPAM, working memory, long-term memory, nonword repetition, vocabulary acquisition, developmental change

    Happiness as stable extraversion : internal consistency reliability and construct validity of the Oxford Happiness Questionnaire among undergraduate students

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    The Oxford Happiness Questionnaire (OHQ) was developed by Hills and Argyle (2002) to provide a more accessible equivalent measure of the Oxford Happiness Inventory (OHI). The aim of the present study was to examine the internal consistency reliability, and construct validity of this new instrument alongside the Eysenckian dimensional model of personality. The Oxford Happiness Questionnaire was completed by a sample of 131 undergraduate students together with the abbreviated form of the Revised Eysenck Personality Questionnaire. The data demonstrated good internal consistency reliability (alpha = .92) and good construct validity in terms of positive association with extraversion (r = .38 p < .001) and negative association with neuroticism (r = −.57 p < .001). The kind of happiness measured by the OHQ is clearly associated with stable extraversion

    HIV infection significantly reduces lipoprotein lipase which remains low after 6 months of antiretroviral therapy

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    Purpose of the study Fractional clearance rate of apolipoprotein B100-containing lipoproteins is reduced in HIV infection before and after antiretroviral (ARV) treatment [1]. We compared lipoprotein lipase (LPL) activity and gene expression in HIV-positive subjects before and 6 months after ARV with HIV-negative controls. Methods Fasting blood post heparin total and hepatic lipase activity,adiponectin, leptin, insulin, glucose, and lipid measurementswere made in 32 HIV-infected and 15 HIVnegative controls. LPL was estimated by subtractinghepatic lipase from total lipase. Adiponectin, LPL andhormone sensitive lipase (HSL) gene expression weremeasured from iliac crest subcutaneous fat biopsies.Patients were tested before, and 6 months after randomisation to AZT/3TC (n = 15) or TDF/FTC (n = 17) with EFV.Between-group comparison was by Mann-Whitney andpaired samples by the Wilcoxon signed rank tests. Summary of results There were no differences in gender, ethnicity, baseline BMI, regional fat distribution (whole body DEXA) and visceral (VAT) and subcutaneous fat (SAT) measured by abdominal CT scans between controls and patients. Trunk fat/BMI ratio, VAT and VAT:SAT ratio significantly increased after 6-month ARV therapy (p = 0.01). There were no differences between groups in serum NEFA,HOMA and leptin levels. Selected other results are shown in Table 1. Conclusion Post heparin lipoprotein lipase activity is reduced in HIV and does not return to control levels after 6 months of ARV therapy. AZT-containing regimens are associated with a greater increase in LPL, LPL gene expression and plasma adiponectin than TDF

    Lexicality and frequency in specific language impairment: accuracy and error data from two nonword repetition tests

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    Purpose: Deficits in phonological working memory and deficits in phonological processing have both been considered potential explanatory factors in Specific Language Impairment (SLI). Manipulations of the lexicality and phonotactic frequency of nonwords enable contrasting predictions to be derived from these hypotheses. Method: 18 typically developing (TD) children and 18 children with SLI completed an assessment battery that included tests of language ability, non-verbal intelligence, and two nonword repetition tests that varied in lexicality and frequency. Results: Repetition accuracy showed that children with SLI were unimpaired for short and simple high lexicality nonwords, whereas clear impairments were shown for all low lexicality nonwords. For low lexicality nonwords, greater repetition accuracy was seen for nonwords constructed from high over low frequency phoneme sequences. Children with SLI made the same proportion of errors that substituted a nonsense syllable for a lexical item as TD children, and this was stable across nonword length. Conclusions: The data show support for a phonological processing deficit in children with SLI, where long-term lexical and sub-lexical phonological knowledge mediate the interpretation of nonwords. However, the data also suggest that while phonological processing may provide a key explanation of SLI, a full account is likely to be multi-faceted

    In-home dementia caregiving is associated with greater psychological burden and poorer mental health than out-of-home caregiving: a cross-sectional study

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    Introduction: Caregivers who live with a person with dementia who receives care, compared with those who live elsewhere, are often considered to experience greater levels of psychological and affective burden. The evidence for this is, however, only limited to studies employing small sample sizes and that failed to examine caregivers’ psychological wellbeing. We address these issues in a large cohort of dementia caregivers. // Methods: We conducted a cross-sectional study comparing caregivers living with a dementia care recipient (n = 240) to caregivers living elsewhere (n = 255) on caregivers’ burden, anxiety, and depression. // Results: We found that caregivers living with the care recipient relative to those living elsewhere showed significantly greater burden and depression, but we found no group difference in anxiety. // Conclusions: Our study adds to the evidence by showing that cohabiting with a care recipient with dementia is associated with greater burden and poorer psychological wellbeing. Strategies aiming to improve caregivers’ burden and psychological wellbeing should take account of caregivers’ living arrangements

    Working memory, phonological awareness, and developing language skills

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    The relationship between working memory, verbal short-term memory, phonological awareness, and developing language skills was explored longitudinally in children growing up in a multilingual society. A sample of 121 children from Luxembourg were followed from the end of Kindergarten to 1st Grade, and completed multiple assessments of verbal short-term memory, complex working memory, phonological awareness, native and foreign vocabulary knowledge, language comprehension, and reading. Results indicate that relations between the measures were best characterized by a model consisting of two related but separable constructs – corresponding to verbal short-term memory and the central executive – that were distinct from phonological awareness. The data further showed that assessments of verbal short-term memory in Kindergarten significantly predicted vocabulary knowledge and comprehension in native and foreign languages one year later: Central executive and verbal short-term memory measures in Kindergarten were significantly associated with reading in 1st Grade and phonological awareness, indexed by rhyme detection, did not predict any of the language constructs one year later. The findings lend strong support to the position that verbal short-term memory is one of the main contributors to new word learning in both native and non-native languages by supporting the formation of stable phonological representations of new words in long-term memory. Verbal short-term memory also seems to play a significant role in the syntactic comprehension of sentences. The heard material might be kept active in verbal short-term memory while the child is listening to the sentence and processing it for comprehension. Finally working memory appears to make significant contributions to reading development. One explanation of these findings is that literacy classroom activities often impose heavy demands on working memory, the capacity of which therefore has a direct effect on the frequency of task failure or success in these classroom activities which consequently influences the rate of learning
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