Biomedical subjects

Murray Maybery

Publications and source records attributed to Murray Maybery.

8 recordsLinked to original sources

PubMed2007

On keeping (intrusive) thoughts to one's self: testing a cognitive model of auditory hallucinations.

BACKGROUND: Previous studies have linked intrusive cognitions (hallucinations and obsessions) with inhibitory dysregulation. Combined deficits in intentional inhibition and context memory have been proposed to explain the intrusive nature and perceived nonself origin of auditory hallucinations (Waters et al., 2006). This study tested the prediction, from this model, that individuals with obsessive-compulsive disorder (OCD), who do not mistake the origin of their intrusive thoughts, will show a deficit of intentional inhibition but intact contextual memory. METHOD: The performance of 14 individuals with OCD and 24 healthy controls was compared on two measures of intentional cognitive inhibition and on a context memory task.Results. Participants with OCD were significantly impaired on both measures of inhibition but were not significantly different from controls in any condition of the context memory task. CONCLUSIONS: The predictions were confirmed. Individuals with OCD, like schizophrenia patients with auditory hallucinations, showed impaired intentional inhibition. This impairment might be responsible for the intrusive thoughts reported in both disorders, and might also partially account for the high rates of comorbidity of OCD and schizophrenia. Finally, intact context memory abilities in OCD may contribute to an efficient memory system, and may differentiate this group from those with hallucinations.

Adult↗

PubMed2006

Characteristics of the broader phenotype in autism: a study of siblings using the children's communication checklist-2.

Non-autistic relatives of people with autistic disorder have an increased risk of social and communicative difficulties: this is known as the "broad phenotype." Better methods for characterizing the broad phenotype are needed to facilitate identification of risk genes for autism. 29 siblings of 20 children with autistic disorder, 13 siblings of 9 children with PDDNOS, and 46 typically developing control children from 26 families were assessed by parental report using the Children's Communication Checklist-2 (CCC-2). Groups were matched on age and IQ and siblings with autism were excluded. Group mean scores on the CCC-2 differed on only one subscale, syntax. However, siblings of children with autism or PDDNOS were over-represented in the tails of the distributions of several scales, and 10 (24%) scored more than 2 SD below the control mean on a total score based on all 10 subscales. Only two of these 10 children scored above threshold on one or more scales of the Autism Diagnostic Interview-Revised (ADI-R). Children with abnormal scores on the CCC-2 total were characterized by low-verbal IQ and their fathers tended to score high on the social and communication scales of the Autism Quotient, a measure of the broad phenotype in adults. The CCC-2 shows promise as a quick screening device for the broad phenotype in non-autistic siblings of children with autism.

Adolescent↗

PubMed2006

Multiple cognitive capabilities/deficits in children with an autism spectrum disorder: "weak" central coherence and its relationship to theory of mind and executive control.

This study examined the validity of "weak" central coherence (CC) in the context of multiple cognitive capabilities/deficits in autism. Children with an autism spectrum disorder (ASD) and matched typically developing children were administered tasks tapping visuospatial coherence, false-belief understanding and aspects of executive control. Significant group differences were found in all three cognitive domains. Evidence of local processing on coherence tasks was widespread in the ASD group, but difficulties in attributing false beliefs and in components of executive functioning were present in fewer of the children with ASD. This cognitive profile was generally similar for younger and older children with ASD. Furthermore, weak CC was unrelated to false-belief understanding, but aspects of coherence (related to integration) were associated with aspects of executive control. Few associations were found between cognitive variables and indices of autistic symptomatology. Implications for CC theory are discussed.

Autistic Disorder↗

PubMed2005

Central coherence in typically developing preschoolers: does it cohere and does it relate to mindreading and executive control?

BACKGROUND: Frith and Happé (1994) describe central coherence (CC) as the normal tendency to integrate individual elements into a coherent whole, a cognitive style which varies in the general population. Individuals with autism are at the extreme (weak) end of the continuum of coherence. There has been debate over whether CC is independent from other psychological functions such as theory of mind and executive control. METHODS: We examined the validity of the CC construct in 76 typically developing 4- and 5-year-old children using four visuospatial coherence tasks. We also investigated the extent to which individual differences in performance on CC measures were associated with individual differences on measures of mindreading and executive functioning (EF). RESULTS: Unexpectedly, the CC variables were not highly intercorrelated and did not form a single coherence factor. Instead, the results revealed a two-factor structure, one of which corresponded to visuospatial constructional ability. Correlations between the emerging factors of coherence and mindreading ability were weak, even when developmental differences in age and verbal and nonverbal ability were taken into account. In contrast, visuospatial constructional ability was reliably related to measures of EF, whilst correlations between EF and the second CC factor were very weak. CONCLUSIONS: CC in typically developing preschoolers is not a unitary construct. Whilst there is little relationship between CC and mindreading abilities in these young children, executive control appears to be associated with one aspect of coherence: visuospatial construction.

Child Development↗

PubMed2004

Abnormal global processing along the dorsal visual pathway in autism: a possible mechanism for weak visuospatial coherence?

Frith and Happe (Frith, U., & Happe, F. (1994). Autism: Beyond theory of mind. Cognition, 50, 115-132) argue that individuals with autism exhibit 'weak central coherence': an inability to integrate elements of information into coherent wholes. Some authors have speculated that a high-level impairment might be present in the dorsal visual pathway in autism, and furthermore, that this might account for weak central coherence, at least at the visuospatial level. We assessed the integrity of the dorsal visual pathway in children diagnosed with an autism spectrum disorder (ASD), and in typically developing children, using two visual tasks, one examining functioning at higher levels of the dorsal cortical stream (Global Dot Motion (GDM)), and the other assessing lower-level dorsal stream functioning (Flicker Contrast Sensitivity (FCS)). Central coherence was tested using the Children's Embedded Figures Test (CEFT). Relative to the typically developing children, the children with ASD had shorter CEFT latencies and higher GDM thresholds but equivalent FCS thresholds. Additionally, CEFT latencies were inversely related to GDM thresholds in the ASD group. These outcomes indicate that the elevated global motion thresholds in autism are the result of high-level impairments in dorsal cortical regions. Weak visuospatial coherence in autism may be in the form of abnormal cooperative mechanisms in extra-striate cortical areas, which might contribute to differential performance when processing stimuli as Gestalts, including both dynamic (i.e., global motion perception) and static (i.e., disembedding performance) stimuli.

Autistic Disorder↗

PubMed2004

Are phonological processing deficits part of the broad autism phenotype?

Two tests of phonological processing, nonword repetition, and nonsense passage reading, were administered to 80 probands with autistic disorder or PDDNOS (index cases) and 59 typically developing controls, together with their parents and siblings. In addition, parents completed a questionnaire about history of language and literacy problems, and all participants were given tests of verbal (VIQ) and performance IQ (PIQ). Parents also completed the Autism-Spectrum Quotient, which was used to index the broad autism phenotype. Index probands scored well below control probands on the two phonological tests. However, on neither phonological measure did index relatives differ from control relatives. Within the index group, there was no relationship between the proband's level of VIQ, or age at achieving phrase speech, and phonological score of relatives. VIQ was the only measure to show any familiality within the index group. Reported history of language and literacy problems did not differentiate index parents from control parents overall, but those who were categorized as cases of the broad phenotype reported more history of language and literacy problems than did other index parents. However, they did not have poorer scores on the phonological measures. It is concluded that phonological processing deficits are not part of the broad autism phenotype.

Articulation Disorders↗

PubMed2004

Using self-report to identify the broad phenotype in parents of children with autistic spectrum disorders: a study using the Autism-Spectrum Quotient.

BACKGROUND: The concept of the 'broad phenotype' of autism refers to the finding that relatives of people with autism often have mild forms of autistic-like characteristics, such as social and communicative difficulties. This study used the Autism Spectrum Quotient (AQ), a questionnaire devised to assess features of the broad phenotype in adults, with parents of people with autism, to see whether they would be more likely to obtain extreme scores than a control group. METHODS: The AQ was administered to parents of 69 people with an autism spectrum disorder and parents of 52 controls. RESULTS: On two of the five subscales of the AQ, social skills and communication, parents of people with autism obtained higher scores than control parents. The other three scales, attention to detail, attention switching, and imagination, did not differentiate groups. The correlation between social skills and communication scales was .663. The scales can be combined to give an index of broad phenotype. CONCLUSIONS: The AQ appears to be sensitive to the broad phenotype, provided attention is restricted to the social skills and communication scales.

Adult↗

PubMed2003

Weak central coherence, poor joint attention, and low verbal ability: independent deficits in early autism.

C. Jarrold, W. Butler, E. M. Cottington, and F. Jiminez (2000) proposed that weak central coherence is a primary cognitive deficit in autism and speculated that it may even account for theory of mind impairments. The current study investigated whether weak central coherence could account for deficits in 2 behaviors purported to tap capabilities fundamental to a theory of mind: joint attention and pretend play. Twenty-one children (ages 3-5 years) with autism spectrum disorders were matched to 21 control children on chronological age, nonverbal ability, and gender. Pretend play did not differentiate the groups. Weak central coherence, poor joint attention, and low verbal ability contributed significantly and independently to the prediction of autism group membership, a finding consistent with 3 independent cognitive deficits underlying autism.

Aptitude↗