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Biomedical subjects

C Hulme

Publications and source records attributed to C Hulme.

54 records · Page 3Linked to original sources
PubMed1993

Short-term memory impairments in Alzheimer-type dementia: evidence for separable impairments of articulatory rehearsal and long-term memory.

Two experiments are described which investigate the short-term memory deficits found in Alzheimer-type dementia. In the first experiment memory span for words of differing spoken duration is related to speech rate. Memory span was lower in subjects suffering from Alzheimer-type dementia than for normal elderly controls but in both cases a linear function related recall to speech rate for items of differing spoken durations. The function for Alzheimer subjects had an equivalent slope (interpreted as reflecting a contribution from a sub-vocal rehearsal process) but a lower intercept (interpreted as reflecting a contribution from a long-term memory component). The second experiment investigated the effects of repeating supra-span lists of items in a serial recall task. As predicted the control subjects showed substantial increases in recall across trials associated with elevations of the speech rate/recall functions while the Alzheimer subjects showed very little benefit from repetition of the lists. We conclude that the verbal short-term memory deficit found in Alzheimer-type dementia has two components: a deficit in the rate of rehearsal and an impairment in the long-term memory component of short-term recall.

Aged↗
PubMed1993

Perceptual grouping in visual word recognition.

Four experiments are presented in which printed texts are read for their meaning. Some of the texts were mutilated by altering the size of selected letters. In Experiments 1, 2, and 3, the number of words mutilated per passage and the number of letters changed per word were both manipulated. In all three experiments, reading was slowed as a function of the number of words changed per passage, while the number of letters changed per word had a much smaller effect. The interaction between the number of words and number of letters changed was not significant in any of the experiments. It is difficult to explain these results merely in terms of changes in the discriminability of letters. In Experiment 2 all uppercase text was used, which argues against an explanation in terms of supraletter features such as word envelope. We propose an explanation in terms of visual attention and the perceptual grouping required prior to feature recognition. The last experiment supports this explanation through the counterintuitive finding that adding letters of intermediate size can improve legibility by allowing grouping processes to associate large and small letters as belonging to the same word object.

Adult↗
PubMed1991

Verbal short-term memory span in speech-disordered children: implications for articulatory coding in short-term memory.

One influential explanation of the development of verbal short-term memory in children argues that short-term memory capacity is a direct function of speech rate. This theory predicts that children with pathologically slow speech will show reduced verbal short-term memory capacity and will show less evidence of speech-base coding on verbal memory tasks. To test this prediction, verbal short-term memory span was assessed using a task that did not require a verbal response in 37 speech-disordered children and 37 age- and sex-matched controls (age range 4-15 years). The speech-disordered group had a significantly lower short-term memory capacity, a smaller word length effect, and reduced speech-motor activity during rehearsal periods. Covariance analyses revealed that these differences were not a function of general intellectual or motor speed differences between the groups, and that speech rate as a covariate abolished group differences in short-term memory. These results suggest that speech rate may be a causal determinant of verbal short-term memory capacity.

Adolescent↗
PubMed1988

Patterns of rotary pursuit performance in clumsy and normal children.

The present study is concerned with the development of motor programs in clumsy children. In order to investigate this, the performance of clumsy and normal children on a rotary pursuit tracking task was compared. The performance of the clumsy group was inferior to that of the control group in terms of time on target, but the pattern of performance across successive trials was broadly similar for the two groups, suggesting a progression from control by visual feedback to control by motor programs. It was concluded that the performance of clumsy children on the rotary pursuit task may be limited more by impaired visual feedback control than by an impairment in the ability to develop motor programs.

Attention↗
PubMed1987

Perceptual judgments of normal and clumsy children.

The performance of normal and clumsy children was compared on a range of measures of visuo-spatial perception. It was found that the clumsy children performed more poorly than the normal children on size-constancy judgements and area, slope, spatial position and linear length discriminations. The differences could not be explained by variations in visual acuity. These results are discussed in terms of information-processing models of motor control, and their possible implications for the assessment and treatment of clumsy children are briefly outlined.

Child↗
PubMed1987

Kinaesthetic sensitivity of normal and clumsy children.

Laszlo and Bairstow (1985a) stated that their Kinaesthetic Sensitivity Test (KST) was designed to be useful in researching the relationship between kinaesthesis and motor performance, and as a diagnostic tool to identify children with poor kinaesthetic function. This study examined the claim that many clumsy children perform poorly on the KST. It was found that the test failed to distinguish between the performances of clumsy children and those of an age-matched control group. Because of its psychometric shortcomings, the KST is unable to fulfil the claims of Laszlo and Bairstow, either as a research or a clinical tool.

Child↗
PubMed1983

Visual, kinaesthetic and cross-modal development: relationships to motor skill development.

The ability of children between the ages of 5 and 10 years to match the length of lines within and between the modalities of vision and kinaesthesis was studied. No evidence was found for specific increases in cross-modal skill which could not be explained in terms of within-modal development. Performance in the perceptual task was related to measures of developing motor skill in the children. Substantial relationships were found between performance on the within-modal tasks and motor skill, but no significant relationships were found between cross-modal measures and motor skill development. It is concluded that the development of cross-modal integration is not a major determinant of motor skill development.

Child↗
PubMed1983

Intelligence and inspection time in normal and mentally retarded subjects.

The present experiments explore the generality of some recent findings relating IQ to a measure known as Inspection Time (IT)--the exposure duration necessary to judge which of two briefly presented straight lines is the longer. In the first study IT and verbal and performance IQ scores were obtained from a large group of normal six- and seven-year-old children. In contrast to some previous suggestions verbal IQ and full-scale IQ did not correlate significantly with IT, and performance IQ showed only a weak correlation with IT (r = -0.29). In the second experiment IT was found to correlate much more highly with performance IQ in a sample of mentally retarded subjects (r = -0.71). Some possible implications of these results for theories of intelligence and of mental retardation are discussed.

Adult↗
PubMed1982

Visual perceptual deficits in clumsy children.

In a previous study clumsy children were found to be impaired in their ability to match the length of successively presented straight lines, and the ability to perform this task correlated with their degree of motor impairment [3]. The present experiments explore two possible explanations for this pattern of results. One possibility is that this earlier result tapped a memory deficit in the clumsy children. The first experiment shows that the clumsy children still experience difficulties in matching the length of a line to a second line which is simultaneously present. This suggests the difficulty is one of perception and not memory. The second experiment explores whether faulty perception of length in the clumsy children is related to eye movement problems. No support for this idea was found; with tachistoscopic presentations at durations which exclude subjects making eye movements the clumsy children are still clearly impaired in judging the length of lines.

Child↗
PubMed1982

Visual, kinaesthetic and cross-modal judgements of length by normal and clumsy children.

The ability of normal and clumsy children to match the length of lines within and between the modalities of vision and kinesthesis was studied. The clumsy children showed perceptual impairments, as indicated by their poor performance on the visual, kinaesthetic and cross-modal judgements of length and also by their low scores on spatial subtests of the WISC. Variations in motor skill correlated with performance on the visual perceptual measures, but not with performance on the kinaesthetic or cross-modal tasks. The idea that clumsiness may be caused by an impairment of visual perception is discussed, together with some alternative interpretations of this pattern of results.

Agnosia↗
PubMed1979

The connection between different verbal difficulties in a backward reader.

The case is reported of a body of normal intelligence who is backward in reading and had associated difficulties in verbal expression, auditory sequential memory and visual association. The major problem seemed to be an inability to recall appropriate words. To aid efficient retrieval, words of personal interest were used, which were made tangible by means of plastic script letters. Progress had been made with these methods and it is suggested that remediation may be misdirected if the primary language retrieval problem is overlooked in such cases.

Adolescent↗
PubMedDate not supplied

Visual, kinaesthetic and cross-modal judgments of length by clumsy children: a comparison with young normal children.

In a previous study, clumsy children, when compared to normal children of the same age, were found to be impaired in their ability to match the length of successively presented straight lines within and between the modalities of vision and kinaesthesis. The present study explores this finding further by comparing the clumsy children's performance with that of a group of younger normal children whose skills of movement are comparable to those of the clumsy children. It was found that the clumsy children's performance on the perceptual measures was equivalent to that of the younger normal children.

Child↗
PubMedDate not supplied

Clumsy children--a review of recent research.

Clumsy children have severe problems in developing adequate skills of movement in the absence of general sensory and intellectual impairments and without showing signs of overt neurological damage. Descriptive studies indicate a variety of characteristics which are typical of these children including difficulties with feeding and dressing, poor drawing and writing skills, and lower performance than verbal IQ. Studies which explore the underlying functional impairments in these children are reviewed, with an emphasis on the methodological problems inherent in demonstrating causal influences. It is concluded that attempts to relate clumsiness to impairments of visual and kinaesthetic perception, although as yet inconclusive, are worthy of further study.

Child↗