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Biomedical subjects

D V Bishop

Publications and source records attributed to D V Bishop.

At least 19 recordsLinked to original sources
PubMed1992

Manipulation of visual mental images in children and adults.

Recently, there has been a debate on whether visual patterns can be transformed and reinterpreted in mental imagery. In the present study, task demands and age of subjects were manipulated to see whether children and adults were able to discover a novel visual pattern after transforming a mental image. Two tasks, called combination and subtraction, were devised. They consist of either compounding or taking away parts of images to discover a new construal. Results indicate that not only adults, but also children aged 6 and 10, are able to transform a mental image so as to yield another image with a different interpretation. Task demands had a greater effect on children than adults, consistent with the suggestion that the ease of manipulating mental images is a function of the efficiency of control processes.

Adult↗
PubMed1992

The measurement of handedness: a cross-cultural comparison of samples from England and Papua New Guinea.

Handedness was compared in 125 English children and 185 young people from Papua New Guinea (PNG). Many of the latter were unfamiliar with implements such as pencils and spoons. The PNG subjects showed strong hand preferences, usually for the right, and on some items were more consistent in hand use than the English subjects. However, they had smaller hand differences on peg-moving and tapping than the English children. A factor analysis identified one factor with high loadings from items involving precise motor control, and another with positive loadings from only card-dealing, block-building and threading. The first factor was impervious to cultural influences, whereas the second showed considerable cultural variation.

Adolescent↗
PubMed1992

Influence of short-term memory codes on visual image processing: evidence from image transformation tasks.

Three experiments showed that phonological recording of visual stimuli in short-term memory (STM) affects coding in long-term memory (LTM) and therefore performance on tasks involving generation and manipulation of visual images of the stimuli. An image transformation task was devised. It consists of mentally subtracting a part of an image to discover in the remainder another object. In Experiment 1, Ss were required to learn a set of easily nameable visual stimuli and then perform the subtraction task on images retrieved from LTM. Performance was significantly better when initial learning was accompanied by articulatory suppression (AS). Experiment 2 confirmed that AS had no effect when the task was performed on an image of a just-presented stimulus. In Experiment 3, the nameability of the stimuli was manipulated. The results replicated the effect of AS for items that were easy to name but showed no effect of AS for stimuli that were difficult to name.

Adult↗
PubMed1992

Comprehension problems in children with specific language impairment: literal and inferential meaning.

A group of 61 schoolchildren with specific language impairment (SLI) was compared with a control group on a comprehension task, in which the child was questioned about a story that had been presented either orally or as a series of pictures. Half the questions were literal, requiring the child to provide a detail that had been mentioned or shown explicitly in the story. The remainder required the child to make an inference about what had not been directly shown or stated. SLI children were impaired on this task, even after taking into account "comprehension age," as assessed on a multiple-choice test. However, the effects of mode of presentation and question type were similar for control and SLI groups. Children who fitted the clinical picture of semantic-pragmatic disorder had lower scores than other SLI children on this task. In addition, they were more prone to give answers that suggested they had not understood the question. However, as with the other SLI children, there was no indication that they had disproportionate difficulty with inferential questions. It is concluded that SLI children are impaired in constructing an integrated representation from a sequence of propositions, even when such propositions are presented nonverbally.

Child↗
PubMed1992

Clumsiness and perceptual problems in children with specific language impairment.

Clumsiness is frequently noted among children with developmental language disorders. This study considered whether the pattern of motor and perceptual impairments in language-disordered children is similar to that described previously in 'clumsy children' without language difficulties. 17 children with specific language impairment (SLI) were compared with 17 normal controls, matched for age, sex, performance IQ and socio-economic status. The SLI children did more poorly than controls on a test battery assessing motor skills and visual discrimination. There was no evidence of lateralised impairments. It is concluded that developmental clumsiness in SLI children is similar to that seen in clumsy children who are not language-impaired, and that their sensorimotor deficits extend to visual discrimination tasks that have no motor component and do not involve transient stimuli.

Child↗
PubMed1992

Verbal recoding of visual stimuli impairs mental image transformations.

Two experiments were carried out to test the hypothesis that verbal recoding of visual stimuli in short-term memory influences long-term memory encoding and impairs subsequent mental image operations. Easy and difficult-to-name stimuli were used. When rotated 90 degrees counterclockwise, each stimulus revealed a new pattern consisting of two capital letters joined together. In both experiments, subjects first learned a short series of stimuli and were then asked to rotate mental images of the stimuli in order to detect the hidden letters. In Experiment 1, articulatory suppression was used to prevent subjects from subvocal rehearsal when learning the stimuli, whereas in Experiment 2, verbal labels were presented with each stimulus during learning to encourage a reliance on the verbal code. As predicted, performance in the imagery task was significantly improved by suppression when the stimuli were easy to name (Experiment 1) but was severely disrupted by labeling when the stimuli were difficult to name (Experiment 2). We concluded that verbal recoding of stimuli in short-term memory during learning disrupts the ability to generate veridical mental images from long-term memory.

Attention↗
PubMed1990

Handedness, clumsiness and developmental language disorders.

Hand preference and relative hand skill were assessed in 83 8 1/2-year-olds who had first been enrolled in a longitudinal study of specific language impairment at 4 years of age. There was no evidence that hand preference or relative skill of the two hands differed from normal in this population, although skill of both hands was poor in children with persisting language difficulties.

Child↗
PubMed1990

On the futility of using familial sinistrality to subclassify handedness groups.

Annett's right shift model was used to show that presence of left-handedness in parents or grandparents is an extremely weak indicator of whether or not a person's handedness is influenced by genetic factors. Furthermore, where a genetic influence is present, familial sinistrality is only weakly related to underlying genotype. The usual rationale given for subdividing handedness groups according to familial sinistrality is logically indefensible.

Functional Laterality↗
PubMed1990

The relationship between phoneme discrimination, speech production, and language comprehension in cerebral-palsied individuals.

Twenty-four individuals with impaired speech (anarthria or dysarthria) were compared on tests of receptive language to a control group with normal speech. All subjects were cerebral-palsied and groups were matched on age and nonverbal ability. The speech-impaired subjects performed less well than controls on a phoneme discrimination task in which they were required to judge whether pairs of nonwords were the same or different. They were also impaired relative to controls on a receptive vocabulary test, but not in understanding of grammatical structure. One year later, phoneme discrimination skills were reassessed in this sample, using another same-different task, plus a new task in which subjects were required to judge if the name of a picture was spoken correctly or altered by one sound. Speech-impaired subjects performed as well as controls on the word judgment task, indicating that they can discriminate phoneme contrasts adequately. However, the same-different task again resulted in highly significant differences between speech-impaired and control groups. It is concluded that poor performance on the same-different task reflects weak memory for novel phonological strings, rather than impaired phoneme perception. It is proposed that retention of unfamiliar words is facilitated by overt or covert repetition, so individuals who cannot speak fluently have difficulty remembering nonwords. This explanation can account both for the poor performance of speech-impaired subjects on the same-different task, and for their selective deficit in vocabulary acquisition.

Adolescent↗
PubMed1990

How to increase your chances of obtaining a significant association between handedness and disorder.

Handedness inventory data are peculiarly prone to be used to classify subjects in a post hoc fashion. Data from a computer simulation are used to show that if this procedure is adopted, significance levels can be seriously misleading: under certain conditions the odds of obtaining "significant" results by chance are as high as 2:3. Specification of cutoffs after inspection of the data is probably the most important source of spurious associations between handedness and disorder.

Bias↗
PubMed1990

A prospective study of the relationship between specific language impairment, phonological disorders and reading retardation.

Language and literacy skills were assessed in 83 8 1/2-year olds whose language development had been impaired at 4 years of age. Provided that language problems had resolved by age 5 1/2 years, literacy development was normal, but many of the children who still had verbal deficits at 5 1/2 years of age did have reading difficulties and persisting oral language impairments later on. In these children, reading comprehension tended to be poor relative to reading accuracy. Syntactic competence in the preschool period accounted for a substantial proportion of the variance in literacy attainments, after allowing for the effects of non-verbal ability. There were only weak links between expressive phonological disorders and later ability to read either meaningful text or non-words.

Articulation Disorders↗
PubMed1989

Accurate non-word spelling despite congenital inability to speak: phoneme-grapheme conversion does not require subvocal articulation.

Previous work has shown that children with motor speech disorders (dysarthria) have no particular difficulty in spelling non-words containing sounds that they cannot produce accurately in their own speech. This suggests that subvocal articulation is not implicated in generating a graphemic representation from a phonological string. However, it could be argued that, although severely unintelligible, dysarthric individuals may be able to use their own articulation as a basis for translating between phonemes and graphemes. In this study we investigated spelling of words and non-words in cerebral palsied individuals, including speechless (anarthric) as well as dysarthric subjects. Although spelling abilities of these individuals were below control levels, there was no evidence that different processes were used, and one anarthric individual achieved perfect performance in spelling a list of non-words which included consonant clusters. It is concluded that spelling by the 'indirect' route can be achieved in the absence of any articulation.

Adolescent↗
PubMed1989

Does hand proficiency determine hand preference?

There is debate in the handedness literature over proficiency and preference measures are indicators of common underlying factors, or separate dimensions of behavior with different causes. It has been argued that hand preference has different origins from hand proficiency on the grounds that (i) the two types of measure are imperfectly correlated and (ii) distributions of relative hand proficiency are normal or nearly so, whereas distributions of hand preference are J-shaped. A model is described in which the probability that one hand will be preferred for a given activity is directly proportional to the relative proficiency of the two sides, the latter being normally distributed. It is shown that imperfect correlations between proficiency and preference measures, and J-shaped distributions of preference, can be predicted by such a model. These facts about hand preference and proficiency do not, therefore, go against the view that preference is determined by proficiency.

Functional Laterality↗
PubMed1989

Unfixed reference, monocular occlusion, and developmental dyslexia--a critique.

Stein and Fowler have proposed that poor binocular control of vergence eye movements is responsible for reading problems in a subset of dyslexic children, and that this subgroup is characterised by unstable performance on Dunlop's reference eye test. Four predictions from this hypothesis are evaluated in the light of published evidence. First, it is shown that a substantial minority of good readers have unfixed reference. Second, the evidence for a raised prevalence of unfixed reference in dyslexics is reviewed and contradictory findings are discussed. Third, it is argued that there is little support for the view that dyslexics with unfixed reference make different types of reading errors from those with fixed reference: indeed many dyslexics with unfixed reference have non-visual, phonological difficulties. Finally, it is argued that studies which claim that monocular occlusion is a successful treatment for 'visual dyslexia' are methodologically flawed and do not provide convincing evidence for this view.

Child↗
PubMed1989

Autism, Asperger's syndrome and semantic-pragmatic disorder: where are the boundaries?

The diagnostic criteria for autism have been refined and made more objective since Kanner first described the syndrome, so there is now reasonable consistency in how this diagnosis is applied. However, many children do not meet these criteria, yet show some of the features of autism. Where language development is impaired, such children tend to be classed as cases of developmental dysphasia (or specific language impairment) whereas those who learn to talk at the normal age may be diagnosed as having Asperger's syndrome. It is argued that rather than thinking in terms of rigid diagnostic categories, we should recognise that the core syndrome of autism shades into other milder forms of disorder in which language or non-verbal behaviour may be disproportionately impaired.

Autistic Disorder↗
PubMed1989

Conversational characteristics of children with semantic-pragmatic disorder. I: Exchange structure, turntaking, repairs and cohesion.

Conversational samples were obtained from 57 children aged from 8 to 12 years with specific language impairment, and 67 control children aged from 4 to 12 years. Fourteen of the language-impaired children fitted the clinical description of semantic-pragmatic disorder. It was found that exchange structure, turntaking, conversational repair and use of cohesive devices could be assessed with adequate inter-rater and test-retest reliability. Children with semantic-pragmatic disorder produced more initiations than other children. Some of these children also violated turntaking rules by interrupting the conversational partner to an unusual degree. Use of cohesion was normal for children with semantic-pragmatic disorder, but limited in other language-impaired children. Analysis of conversations may be more useful than conventional language tests for identifying linguistic abnormalities in children with semantic-pragmatic disorder.

Child↗
PubMed1989

Conversational characteristics of children with semantic-pragmatic disorder. II: What features lead to a judgement of inappropriacy?

Independent raters scanned transcribed conversations from 57 language-impaired children and 67 control children aged from 4 to 12 years and identified instances where the normal flow of conversation appeared to be disrupted because the child's utterance was in some way inappropriate. It was found that adequate inter-rater reliability could be obtained using this procedure. Furthermore, test-retest correlations for inappropriacy were significant, indicating that this is a stable conversational characteristic. The measure of inappropriacy decreased with age in control children, and it distinguished language-impaired from control children. Those identified as having 'semantic-pragmatic disorder' obtained particularly high scores. In a subsidiary analysis, inappropriate responses were subcategorised. A wide range of semantic, syntactic and pragmatic peculiarities was identified as leading to a sense of inappropriacy. Some instances of inappropriacy appeared to indicate cognitive rather than linguistic difficulties. Children with semantic-pragmatic disorder resembled younger normal children in that they frequently misunderstood the literal or implicit meaning of adult utterances and they violated normal rules of exchange structure. In other respects, however, the semantic-pragmatic group did not resemble normally developing children of any age. In particular, they tended to provide the listener with too much or too little information.

Child↗