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Biomedical subjects

Patrick Bolton

Publications and source records attributed to Patrick Bolton.

15 recordsLinked to original sources
PubMed2006

Genetic heterogeneity between the three components of the autism spectrum: a twin study.

OBJECTIVE: This study investigated the etiology of autistic-like traits in the general population and the etiological overlap between the three aspects of the triad of impairments (social impairments, communication impairments, restricted repetitive behaviors and interests) that together define autism spectrum disorders. METHOD: Parents of 3,400 8-year-old twin pairs from the Twins Early Development Study completed the Childhood Asperger Syndrome Test, a screening instrument for autism spectrum symptoms in mainstream samples. Genetic model-fitting of categorical and continuous data is reported. RESULTS: High heritability was found for extreme autistic-like traits (0.64-0.92 for various cutoffs) and autistic-like traits as measured on a continuum (0.78-0.81), with no significant shared environmental influences. All three subscales were highly heritable but showed low covariation. In the genetic modeling, distinct genetic influences were identified for the three components. CONCLUSIONS: These results suggest the triad of impairments that define autism spectrum disorders is heterogeneous genetically. Molecular genetic research examining the three components separately may identify different causal pathways for the three components. The analyses give no indication that different genetic processes affect extreme autistic impairments and autistic impairments as measured on a continuum, but this can only be directly tested once genes are identified.

Asperger Syndrome↗
PubMed2006

The Childhood Asperger Syndrome Test (CAST): test-retest reliability.

The Childhood Asperger Syndrome Test (CAST) is a 37-item parental self-completion questionnaire to screen for autism spectrum conditions in research. Good test accuracy was demonstrated in studies with primary school aged children in mainstream schools. The aim of this study was to investigate the test-retest reliability of the CAST. Parents of 1000 children in years 1-6 in five mainstream primary schools in Cambridgeshire received the CAST. A second identical questionnaire was posted to respondents after approximately 2 weeks. Both mailings generated 136 responses. Agreement above and below a screening cut-point of 15 was investigated. The kappa statistic for agreement (< 15 versus > or = 15) was 0.70, and 97 percent (95 percent CI: 93-99 percent) of children did not move across the cut-point of 15. The correlation between the two test scores was 0.83 (Spearman's rho). The CAST has shown good test-retest reliability, and now requires further investigation in a high-scoring sample.

Asperger Syndrome↗
PubMed2006

Episodic psychiatric disorders in teenagers with learning disabilities with and without autism.

BACKGROUND: Mental health problems in people with learning disabilities and autism are poorly understood. AIMS: To investigate the prevalence of episodic psychiatric disorders in a sample of teenagers with learning disabilities with and without autism. METHOD: Teenagers with learning disabilities living in one geographical area were identified. Those with autism were matched to those without. A semi-structured investigator-based interview linked to Research Diagnostic Criteria was used to assess prevalence and type of episodic disorders. RESULTS: Significantly more individuals with autism had a lifetime episodic disorder, most commonly major depression. Two individuals with autism had bipolar affective disorder. Other episodic disorders with mood components and behaviour change were also evident, as were unclassifiable disorders characterised by complex psychiatric symptoms, chronicity and general deterioration. Antipsychotics and stimulants were most frequently prescribed; the former associated with episodic disorder, the latter with autism. CONCLUSIONS: Teenagers with learning disabilities and autism have higher rates of episodic psychiatric disorders than those with learning disabilities alone.

Adolescent↗
PubMed2005

Consensus clinical guidelines for the assessment of cognitive and behavioural problems in Tuberous Sclerosis.

Tuberous Sclerosis (TSC) is a genetic disorder characterised by abnormal growths in a wide range of organs. In the brain, abnormalities of differentiation, proliferation and migration can produce a range of neuropsychiatric features such as mental retardation, autism and ADHD. Although these manifestations are not diagnostic of the disorder, cognitive and behavioural features are often of greatest concern to families yet limited clinical assessment and interventions are currently offered. A consensus panel at a TSC Brain/Behaviour workshop recommended that the cognitive and behavioural profiles of individuals with TSC should be assessed at regular intervals in a planned fashion in accordance with the difficulties associated with the disorder. Evaluations should include the use of standardised neuropsychological and behavioural tools as appropriate to the age and developmental level of the individual assessed. These cognitive and behavioural profiles should be incorporated in the overall formulation of the needs of the person with TSC to plan educational, social and clinical management strategies. Assessments should be documented so that individual longitudinal progress can be monitored. The paper outlines the problems associated with TSC, the purpose of recommended assessments, developmentally appropriate stages for assessment, and identifies specific areas that should be targeted for assessment.

Adolescent↗
PubMed2005

Neural correlates of eye-gaze detection in young children with autism.

Various reports have demonstrated difficulties in eye-gaze processing in older children and adults with autism. However, little is known about the neural or developmental origin of such difficulties. In the present study, we used high-density Event-Related Potentials (HD-ERPs) to record the neural correlates of gaze processing in young children with autism, and their age-matched controls. In addition, to determine normal gaze processing development we also tested a non-autism adult group. The data obtained from the children with autism resembled that previously observed in typical 4-month old infants. In contrast, the control group showed the same pattern as typical adults. These findings suggest that the neural correlates of gaze direction processing may be delayed in young children with autism.

Adult↗
PubMed2005

The CAST (Childhood Asperger Syndrome Test): test accuracy.

The Childhood Asperger Syndrome Test (CAST) is a parental questionnaire to screen for autism spectrum conditions. In this validation study, the CAST was distributed to 1925 children aged 5-11 in mainstream Cambridgeshire schools. A sample of participants received a full diagnostic assessment, conducted blind to screen status. The sensitivity of the CAST, at a designated cut-point of 15, was 100 percent, the specificity was 97 percent and the positive predictive value was 50 percent, using the group's consensus diagnosis as the gold standard. The accuracy indices varied with the case definition used. The sensitivity of the accuracy statistics to case definition and to missing data was explored. The CAST is useful as a screening test for autism spectrum conditions in epidemiological research. There is not currently enough evidence to recommend the use of the CAST as a screening test within a public health screening programme in the general population.

Asperger Syndrome↗
PubMed2004

Standardized whole brain mapping of tubers and subependymal nodules in tuberous sclerosis complex.

Tuberous sclerosis complex is associated with radiologically visible abnormalities of brain structure, principally tubers and subependymal nodules. We reviewed the literature on neuroimaging of tubers and subependymal nodules and found qualitative evidence of bilateral, predominantly frontal distribution of tubers and bilateral, predominantly subcortical distribution of subependymal nodules in prior studies of pediatric samples. We studied 25 high-functioning adults with tuberous sclerosis complex and normal IQ, acquiring both dual spin-echo and fluid-attenuated inversion recovery magnetic resonance imaging sequences to optimize radiologic diagnosis of tubers and nodules. Individual lesion maps were then coregistered in a standard stereotactic space to facilitate construction of lesion density maps and estimation of lesion density in cortical and subcortical regions reliably defined by a parcellated template image. We found the highest frequency of tubers in frontal lobes and the highest density of tubers in parietal regions. There was significant regional variation in tuber density but no significant lateralization of frequently bilateral tubers. Nodules were located predominantly in the caudate nucleus and were not significantly lateralized. Tuber and nodule volumes were significantly positively correlated. Tuber volume was larger, on average, in patients with a lifetime history of epilepsy, but there was no correlation between IQ and these measures of lesion load. Contemporary image processing tools can be used to enhance quantitative, whole brain analysis of lesion load in patients with tuberous sclerosis complex.

Adolescent↗
PubMed2003

A comparison of morbidity and services provided in three primary care settings.

OBJECTIVE: To describe and compare the pattern of morbidity in a general practice casualty with primary care patients in emergency departments (EDs). SETTING AND SUBJECTS: Patients presenting to a general practice casualty and primary care patients in two EDs in Sydney, NSW. RESULTS: The pattern of morbidity in the general practice casualty was similar to that among ambulatory patients in EDs. CONCLUSION: Opportunities may exist to substitute care between casualty services provided by GPs and those provided in EDs.

Chronic Disease↗
PubMed2003

Sustaining quality general practice in a flawed market.

BACKGROUND: Recent years have seen an increasing corporatization of general practice. OBJECTIVE: This paper considers how divisions of general practice should respond to the corporatization of general practice. DISCUSSION: Corporate models are an economically rational outcome of structural features of Medicare funding for Australian general practice. One limitation of these structures is that they are indifferent to quality. Corporate general practice competes with divisions of general practice at some level because it provides an alternative organisational structure and service values for large numbers of general practitioners. Accepting this, the challenge for divisions becomes one of differentiating themselves from the corporate model through a focus on promoting and encouraging quality practice.

Australia↗
PubMed2002

HealthConnect: a trial of an after-hours telephone triage service.

This paper describes HealthConnect, an after-hours telephone triage and advice service which operated for 15 months in 2000 and 2001. We describe the service, discuss utilisation and implementation issues, and conclude with a description of the key lessons learned from the trial. The service received over of 12,000 calls, of which over half were for information rather than immediately seeking care. Continuing marketing appears to be required in order to ensure ongoing demand for services of this kind. Quality assurance is essential to ensure that an optimal service is provided, and staff recruitment and training are critical to this. A national standardised approach to services of this kind is desirable to provide a consistent service to consumers and realise economies of scale.

Clinical Protocols↗
PubMed2002

The CAST (Childhood Asperger Syndrome Test): preliminary development of a UK screen for mainstream primary-school-age children.

The article describes a pilot and follow-up study of the preliminary development of a new tool to screen for Asperger syndrome (AS) and related social and communication conditions (the Childhood Asperger Syndrome Test, CAST) in children aged 4-11 years, in a non-clinical setting. In the pilot study, parents of 13 children with AS and of 37 typically developing children completed the CAST. There were significant differences between the AS and typical sample means. The pilot was used to establish preliminary cut-off scores for the CAST. In the main study, parents of 1150 primary-school-age children were sent the CAST, and 174 took part in the full data analysis. Results suggest that compared with other tools currently available, the CAST may be useful for identifying children at risk for AS and related conditions, in a mainstream non-clinical sample. Further research is ongoing.

Asperger Syndrome↗
PubMed2002

Brief report: prevalence of autism spectrum conditions in children aged 5-11 years in Cambridgeshire, UK.

The study aimed to establish prevalence of the broader autistic spectrum, including Asperger syndrome, in 5- to 11-year-olds in Cambridgeshire, UK. Cases of diagnosed autism spectrum condition (ASC) in children who were in Cambridgeshire schools and aged between 5 and 11 years on 31 December 1999 were sought using public records, screening instruments, educational psychology and special educational needs coordinator (SENCO) records. We report a prevalence of ASC in the age group 5-11 years of almost 0.6 percent (57 in 10,000). This is 11 times higher than the rate of classic autism but in line with other recent national and international rates for the broader spectrum. In the responding mainstream schools the prevalence was 0.33 percent. In the responding special school population it was 12.5 percent. The overall sex ratio of the children with ASC replicated findings for classical autism of 4:1 (M:F), but in those children being educated in mainstream schools the sex ratio was 8:1 (M:F).

Autistic Disorder↗