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Biomedical subjects

U Frith

Publications and source records attributed to U Frith.

At least 19 recordsLinked to original sources
PubMed1997

The impact of orthographic consistency on dyslexia: a German-English comparison.

We examined reading and phonological processing abilities in English and German dyslexic children, each compared with two control groups matched for reading level (8 years) and age (10-12 years). We hypothesised that the same underlying phonological processing deficit would exist in both language groups, but that there would be differences in the severity of written language impairments, due to differences in orthographic consistency. We also hypothesized that systematic differences due to orthographic consistency should be found equally for normal and dyslexic readers. All cross-language comparisons were based on a set of stimuli matched for meaning, pronunciation and spelling. The results supported both hypotheses: On a task challenging phonological processing skills (spoonerisms) both English and German dyslexics were significantly impaired compared to their age and reading age controls. However, there were extremely large differences in reading performance when English and German dyslexic children were compared. The evidence for systematic differences in reading performance due to differences in orthographic consistency was similar for normal and for dyslexic children, with English showing marked adverse effect on acquisition of reading skills.

Adolescent↗
PubMed1996

'Theory of mind' in the brain. Evidence from a PET scan study of Asperger syndrome.

The ability to attribute mental states to others ('theory of mind') pervades normal social interaction and is impaired in autistic individuals. In a previous positron emission tomography scan study of normal volunteers, performing a 'theory of mind' task was associated with activity in left medial prefrontal cortex. We used the same paradigm in five patients with Asperger syndrome, a mild variant of autism with normal intellectual functioning. No task-related activity was found in this region, but normal activity was observed in immediately adjacent areas. This result suggests that a highly circumscribed region of left medial prefrontal cortex is a crucial component of the brain system that underlies the normal understanding of other minds.

Adult↗
PubMed1996

Is developmental dyslexia a disconnection syndrome? Evidence from PET scanning.

A rhyming and short-term memory task with visually presented letters were used to study brain activity in five compensated adult developmental dyslexics. Their only cognitive difficulty was in phonological processing, manifest in a wide range of tasks including spoonerisms, phonemic fluency and digit naming speed. PET scans showed that for the dyslexics, a subset only of the brain regions normally involved in phonological processing was activated: Broca's area during the rhyming task, temporo-parietal cortex during the short- term memory task. In contrast to normal controls these areas were not activated in concert. Furthermore the left insula was never activated. We propose that the defective phonological system of these dyslexics is due to weak connectivity between anterior and posterior language areas. This could be due to a dysfunctional left insula which may normally act as an anatomical bridge between Broca's area, superior temporal and inferior parietal cortex. The independent activation of the posterior and anterior speech areas in dyslexics supports the notion that representations of unsegmented and segmented phonology are functionally and anatomically separate.

Adult↗
PubMed1996

The neuropsychology of autism.

In this review, we aim to bring together major trends in autism research at three levels: biology, behaviour and cognition. We propose that cognitive theories are vital in neuropsychology, which seeks to make connections between brain abnormality and behavioural symptoms. Research at each of the three levels is incomplete, but important advances have been made. At the biological level, there is strong evidence for genetic factors, although the mechanism is, as yet, unknown. At the behavioural level, diagnosis and education are becoming more coherent and less controversial, although the possibility of autism subtypes has provoked new debate. At the cognitive level, three major theories are proving fruitful (mentalizing impairment, executive dysfunction and weak central coherence), although the relation and overlap between these is uncertain. Rapidly advancing technology and methodology (e.g. brain imaging, gene mapping), as tools of cognitive theory, may help to make autism one of the first developmental disorders to be understood at the neuropsychological level.

Autistic Disorder↗
PubMed1996

Cognitive explanations of autism.

A brief review of the theory of mind account of autism is presented. A lack of theory of mind in autism is well supported by empirical studies and can explain quite specifically the nature of the social communication impairments. Other characteristic behavioural features of autism, in particular perseveration and rigidity, are tackled by the hypothesis of executive function deficits. The theory of weak central coherence attempts to explain the uneven pattern of intellectual abilities seen in autistic individuals, proposing that they adopt a distinctive cognitive style. It is likely that a number of separate cognitive deficits will be identified and that these will provide clues to the underlying brain abnormalities in autism.

Autistic Disorder↗
PubMed1995

Other minds in the brain: a functional imaging study of "theory of mind" in story comprehension.

The ability of normal children and adults to attribute independent mental states to self and others in order to explain and predict behaviour ("theory of mind") has been a focus of much recent research. Autism is a biologically based disorder which appears to be characterised by a specific impairment in this "mentalising" process. The present paper reports a functional neuroimaging study with positron emission tomography in which we studied brain activity in normal volunteers while they performed story comprehension tasks necessitating the attribution of mental states. The resultant brain activity was compared with that measured in two control tasks: "physical" stories which did not require this mental attribution, and passages of unlinked sentences. Both story conditions, when compared to the unlinked sentences, showed significantly increased regional cerebral blood flow in the following regions: the temporal poles bilaterally, the left superior temporal gyrus and the posterior cingulate cortex. Comparison of the "theory of mind" stories with "physical" stores revealed a specific pattern of activation associated with mental state attribution: it was only this task which produced activation in the medial frontal gyrus on the left (Brodmann's area 8). This comparison also showed significant activation in the posterior cingulate cortex. These surprisingly clear-cut findings are discussed in relation to previous studies of brain activation during story comprehension. The localisation of brain regions involved in normal attribution of mental states and contextual problem solving is feasible and may have implication for the neural basis of autism.

Adolescent↗
PubMed1994

Language and communication in autistic disorders.

Communication problems form one of the key diagnostic criteria for autism, but there is a wide variety of manifestations. The theory that autistic individuals are unable to represent mental states can shed light on both the nature and range of communication impairments. This theory predicts that the specific communication deficit lies in the use of language to affect other minds. Language is not special in this respect, and is important only in so far as it may be used to give evidence of a speaker's thoughts and intentions. Thus, in autism, language level would be expected to relate strongly to performance on standard tests of theory of mind. Normal language acquisition appears to build upon the ability to recognize and orient towards ostensive behaviour. For this reason, it may not be necessary to postulate additional language impairments in order to explain the almost universal prevalence of language delay in children with autism. Autism, then, provides a model for studying the important distinction between language and communication, and demonstrates the vital part which mind-reading plays in normal human verbal and non-verbal interaction.

Autistic Disorder↗
PubMed1994

Sampling the form of inner experience in three adults with Asperger syndrome.

Three adults with Asperger syndrome were invited to talk about their inner experiences, using an experience sampling and interview technique. They reported thoughts primarily or solely in the form of images. By contrast, normal adults previously tested with this technique reported inner experiences of a variety of forms. The present report suggests the feasibility and potential interest of the experience sampling method with high-functioning individuals with autistic disorder.

Adaptation, Psychological↗
PubMed1993

Autism.

Explore the source record for details and available documents.

Autistic Disorder↗
PubMed1993

Why do autistic individuals show superior performance on the block design task?

Systematic variations of the block design task were given to 20 autistic, 33 normal and 12 mildly retarded subjects. Designs were contrasted which were either "whole" or segmented, rotated or unrotated, and which did or did not contain obliques. Only segmentation, but neither of the spatial orientation factors, revealed a significant group difference. Autistic subjects, regardless of age and ability, performed better than controls when presented with unsegmented designs. This result suggests that they need less of the normally required effort to segment a gestalt, and thus supports the hypothesis of weak central coherence as a characteristic of information processing in autism.

Adolescent↗
PubMed1992

Deception and sabotage in autistic, retarded and normal children.

We investigated autistic, mentally retarded, and normal children's ability to deceive or obstruct an opponent. When required to tell a lie (saying that a box was locked) autistic children performed significantly worse than their controls, taking into account mental age. However, they readily prevented a competitor from gaining a reward by physical manipulation (locking a box). Their success on sabotage demonstrated that their failure on deception was not due to an inability to understand the task. Performance on deception was predicted by performance on a false belief attribution task. The present findings confirm that autistic children have a specific deficit in understanding and manipulating beliefs.

Adolescent↗
PubMed1992

Can autism be predicted on the basis of infant screening tests?

The authors examined infant hearing and vision screening tests for a group of children subsequently diagnosed as autistic and compared them with a group of children suffering from non-specific developmental delay, as well as with a random sample of records. Four categories (motor, vision, hearing and language, social) were investigated at three ages: six, 12 and 18 months. The random sample group had a low incidence of reported problems at all ages. The learning-disabled group had a sharp increase in reported abnormalities in all categories at 12 months. The autistic group had a selective increase in the social category alone at 18 months.

Autistic Disorder↗
PubMed1991

The cognitive basis of a biological disorder: autism.

This article summarizes recent evidence indicating that individuals suffering from autism have a specific problem in understanding intentions and beliefs. We propose that this problem arises because they are incapable of forming a special kind of mental representation. A single cognitive deficit defines what is common to all autistic individuals. In contrast there is a wide range of proposals for the biological origins of the disorder.

Autistic Disorder↗
PubMed1990

Prospects for a cognitive neuropsychology of autism: Hobson's choice.

Leslie (1987b) proposed a new, metarepresentational model for the cognition of pretense. This model identified a cognitive component necessary for the normal development of a "theory of mind." In this article, the relation of the child's early affective sensitivities to this component is considered. Early affective sensitivities seem to be cognitively distinct from the metarepresentational component. Childhood autism provides an interesting opportunity to study this problem. Three theoretical possibilities for the pathogenesis of this condition are presented: (a) a basic affective disorder as proposed by Hobson (this issue, p. 114), (b) a basic affective disorder and a basic cognitive disorder jointly, and (c) a basic cognitive disorder. There is little evidence for Option a, and a growing body of evidence supports Option c. Option b is sidelined for the time being on grounds of parsimony. Leslie's original theoretical proposals are revised, and some resulting implications are presented for the future investigation of the cognitive neuropsychology of autism.

Autistic Disorder↗