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Jill Boucher

Publications and source records attributed to Jill Boucher.

15 recordsLinked to original sources
PubMed2006

Temporal cognition in children with autistic spectrum disorders: tests of diachronic thinking.

Impaired diachronic thinking-(the propensity and capacity to think about events spreading across time)-was demonstrated in a 2-Phase study in which children with autism were compared with age and ability matched controls. Identical tests of diachronic thinking were administered in both phases of the study, but to different participant groups, with the same results. The marked impairments shown are therefore robust. Various non-temporal explanations of the findings were eliminated by the results of control tasks in Phase 2. Diachronic thinking did not correlate with verbal or non-verbal ability, age, or mentalising ability, consistent with other evidence of the specificity of diachronic thinking ability. Possible causes of impaired diachronic thinking in autism are discussed.

Adolescent↗
PubMed2006

Disordered connectivity in the autistic brain: challenges for the "new psychophysiology".

In 2002, we published a paper [Brock, J., Brown, C., Boucher, J., Rippon, G., 2002. The temporal binding deficit hypothesis of autism. Development and Psychopathology 142, 209-224] highlighting the parallels between the psychological model of 'central coherence' in information processing [Frith, U., 1989. Autism: Explaining the Enigma. Blackwell, Oxford] and the neuroscience model of neural integration or 'temporal binding'. We proposed that autism is associated with abnormalities of information integration that is caused by a reduction in the connectivity between specialised local neural networks in the brain and possible overconnectivity within the isolated individual neural assemblies. The current paper updates this model, providing a summary of theoretical and empirical advances in research implicating disordered connectivity in autism. This is in the context of changes in the approach to the core psychological deficits in autism, of greater emphasis on 'interactive specialisation' and the resultant stress on early and/or low-level deficits and their cascading effects on the developing brain [Johnson, M.H., Halit, H., Grice, S.J., Karmiloff-Smith, A., 2002. Neuroimaging of typical and atypical development: a perspective from multiple levels of analysis. Development and Psychopathology 14, 521-536]. We also highlight recent developments in the measurement and modelling of connectivity, particularly in the emerging ability to track the temporal dynamics of the brain using electroencephalography (EEG) and magnetoencephalography (MEG) and to investigate the signal characteristics of this activity. This advance could be particularly pertinent in testing an emerging model of effective connectivity based on the balance between excitatory and inhibitory cortical activity [Rubenstein, J.L., Merzenich M.M., 2003. Model of autism: increased ratio of excitation/inhibition in key neural systems. Genes, Brain and Behavior 2, 255-267; Brown, C., Gruber, T., Rippon, G., Brock, J., Boucher, J., 2005. Gamma abnormalities during perception of illusory figures in autism. Cortex 41, 364-376]. Finally, we note that the consequence of this convergence of research developments not only enables a greater understanding of autism but also has implications for prevention and remediation.

Autistic Disorder↗
PubMed2006

Lexical knowledge and lexical use in autism.

One aspect of autistic language that has been infrequently researched is vocabulary and the conceptual knowledge underpinning individual words or word types. In this descriptive study we investigate anomalous vocabulary use in a 70,000-word corpus of conversational autistic language and examine evidence that concept formation, and hence vocabulary, is abnormal in autism. Particular attention is paid to the expression of artifact and temporal concepts which some believe may develop abnormally in autism. Little evidence is found of anomalous use of artifact terms, though errors with temporal (and also spatial) expressions are relatively common. We discuss why this may be and consider several potential explanations for why underlying lexical knowledge in autism may not necessarily be reflected in lexical use.

Adult↗
PubMed2006

Free recall in Williams syndrome: is there a dissociation between short- and long-term memory?

Two experiments used the free recall paradigm to investigate verbal memory abilities in Williams syndrome (WS)--a rare genetic disorder. In an earlier free recall study, Vicari et al. (1996a) reported that, unlike TD controls, children with WS showed a recency effect but failed to show a primacy effect. These authors interpreted their findings as evidence for a dissociation between relatively strong verbal short-term memory and relatively impaired verbal long-term memory. In Experiment 1 of the current study, children with WS and TD controls showed comparable improvements in performance with repeated testing of the same material, indicating similar long-term learning of the test items. Neither group showed evidence of primacy effects. However, the extent of primacy effects in free recall is known to depend on the rehearsal strategy that participants adopt. In Experiment 2, therefore, participants were encouraged to engage in overt cumulative rehearsal. This manipulation resulted in significant and comparable primacy effects in both groups, although neither group demonstrated a significant change in overall performance. There was therefore no evidence from either experiment for a dissociation between short- and long-term verbal memory in WS.

Adolescent↗
PubMed2006

Perceptual similarity in autism.

People with autism have consistently been found to outperform controls on visuo-spatial tasks such as block design, embedded figures, and visual search tasks. Plaisted, O'Riordan, and others (Bonnel et al., 2003; O'Riordan & Plaisted, 2001; O'Riordan, Plaisted, Driver, & Baron-Cohen, 2001; Plaisted, O'Riordan, & Baron-Cohen, 1998a, 1998b) have suggested that these findings might be explained in terms of reduced perceptual similarity in autism, and that reduced perceptual similarity could also account for the difficulties that people with autism have in making generalizations to novel situations. In this study, high-functioning adults with autism and ability-matched controls performed a low-level categorization task designed to examine perceptual similarity. Results were analysed using standard statistical techniques and modelled using a quantitative model of categorization. This analysis revealed that participants with autism required reliably longer to learn the category structure than did the control group but, contrary to the predictions of the reduced perceptual similarity hypothesis, no evidence was found of more accurate performance by the participants with autism during the generalization stage. Our results suggest that when all participants are attending to the same attributes of an object in the visual domain, people with autism will not display signs of enhanced perceptual similarity.

Adult↗
PubMed2005

Gamma abnormalities during perception of illusory figures in autism.

This experiment was designed to test the hypothesis that perceptual abnormalities in autism might be associated with alteration of induced gamma activity patterns overlying visual cortical regions. EEG was recorded from six adolescents with autism and eight controls matched on chronological age, and verbal and nonverbal mental age, whilst identifying the presence or absence of an illusory Kanizsa shape. Although there were no reaction time or accuracy differences between the groups there were significant task-related differences in cortical activity. Control participants showed typical gamma-band activity over parietal regions at around 350 msec post onset of shape trials, similar to gamma patterns found in previous studies with non-impaired adults. In contrast, autistic participants showed overall increased activity, including an early 100 msec gamma peak and a late induced peak, 50 to 70 msec earlier than that shown by the control group. We interpret the abnormal gamma activity to reflect decreased "signal to noise" due to decreased inhibitory processing. In this experiment we did not establish a link between altered perception and abnormal gamma, as the autistic participants' behaviour did not differ from the controls. Future work should be designed to replicate this phenomenon and establish the perceptual consequences of altered gamma activity.

Adolescent↗
PubMed2005

Probed serial recall in Williams syndrome: lexical influences on phonological short-term memory.

Williams syndrome is a genetic disorder that, it has been claimed, results in an unusual pattern of linguistic strengths and weaknesses. The current study investigated the hypothesis that there is a reduced influence of lexical knowledge on phonological short-term memory in Williams syndrome. Fourteen children with Williams syndrome and 2 vocabulary-matched control groups, 20 typically developing children and 13 children with learning difficulties, were tested on 2 probed serial-recall tasks. On the basis of previous findings, it was predicted that children with Williams syndrome would demonstrate (a) a reduced effect of lexicality on the recall of list items, (b) relatively poorer recall of list items compared with recall of serial order, and (c) a reduced tendency to produce lexicalization errors in the recall of nonwords. In fact, none of these predictions were supported. Alternative explanations for previous findings and implications for accounts of language development in Williams syndrome are discussed.

Adolescent↗
PubMed2005

A combined clinical, neuropsychological, and neuroanatomical study of adults with high functioning autism.

INTRODUCTION: Three hypotheses concerning associations between neuroanatomical abnormalities, neuropsychological impairments, and the behavioural manifestations of autism were investigated. The primary hypothesis was that the social interaction impairments diagnostic of autism are associated with deficits of socioemotional perception and abnormalities of the amygdala. One subsidiary hypothesis was that the learning and language impairments that occur in less able individuals with autism are associated with impaired memory, and with abnormalities of hippocampal regions. A second subsidiary hypothesis was that the repetitive behaviour diagnostic of autism is associated with executive deficits and with abnormalities of the prefrontal cortex. Associations between the neuroanatomical regions investigated were also examined. METHODS: Ten adult males with high functioning autism (HFA) were compared with 10 healthy controls matched for age, sex, verbal and nonverbal ability. Hypothesis-driven structural MRI and neuropsychological tests were used to collect neuroanatomical and neuropsychological data on all subjects. A version of the Wing Autism Diagnostic Interview Checklist was used to collect clinical data on the HFA subjects. RESULTS: Strong convergent evidence in support of the amygdala hypothesis was obtained, and preliminary support for the hippocampal/parahippocampal hypothesis. No clear evidence was obtained in support of the prefrontal hypothesis. Patterns of associations amongst volume measures within and between medial temporal and prefrontal regions suggest stronger within-region and weaker between-region associations in the HFA group compared with controls. CONCLUSIONS: These findings are discussed in terms of a model of autism in which selective abnormalities of the amygdala and hippocampus (in all cases) and of the parahippocampal gyrus (in lower functioning cases) are implicated, and in which a disruption of coordinated limbic and prefrontal activity may be critical.

Journal Article↗
PubMed2005

Moral understanding in children with autism.

Children with autism were compared with control groups on their ability to make moral judgements. Participants were presented with pairs of vignettes in which actions were either deliberate or accidental and caused injury to a person or damage to property. Participants were asked to judge which protagonist was the naughtier and to verbally justify this judgement. Results showed that the children with autism were as likely as controls to judge culpability on the basis of motive, and to judge injury to persons as more culpable than damage to property. Children with autism also offered some appropriate verbal justifications for their judgments although most justifications were of poor quality and reiterated the story. Results are discussed in terms of theory of mind and the possible role of deficits in complex reasoning and executive functions.

Autistic Disorder↗
PubMed2004

Counterfactual and mental state reasoning in children with autism.

The contributions of counterfactual conditional reasoning (CCR), belief understanding, and inferential reasoning to the performance of children with autism (CWA) on standard false belief tasks were investigated. To assess the roles of these three factors, we compared the performance of CWA on physical-state CCR tasks (which do not require either an understanding of belief or inferential reasoning); on Wellman and Bartsch's (1988) nonstandard tests of false belief (which require an understanding of belief, but not CCR or inferential reasoning), and on standard tests of false belief tasks. The CWA were impaired relative to controls on the physical-state CCR and standard false-belief tasks, but not on the nonstandard false-belief tasks, and the CWA's performance on the physical-state CCR and standard false-belief tasks correlated highly, even when the effects of verbal ability were partialled out. Finally, the CWA's performance on standard false-belief tasks was more impaired than their performance on the physical-state CCR tasks. We concluded that impaired performance on standard false-belief tasks in autism is associated with defective competence in CCR (or some of its component skills), plus defective competence in inferential reasoning and possibly generativity, but that impaired performance is not caused by an inadequate understanding of belief. The results are discussed in relation to other hypotheses concerning the cause or causes of impaired performance on standard false-belief tasks in children with autism.

Autistic Disorder↗
PubMed2003

Language development in autism.

In this short review article, a summary of the behavioural impairments most commonly associated with the spectrum of autism-related disorders is presented, with a slightly amplified account of the defining communication impairment. The patterns of language ability and disability which typically occur in some forms of autism are then outlined, followed by a short section on possible cognitive, or psychological, explanations of these patterns. In particular, the hypothesis that defective socio-affective and socio-cognitive ('theory of mind') causes language impairments, and the hypothesis that temporal processing deficits cause these impairments, are outlined and briefly discussed. An extensive list of references is included, to support and amplify the summary data included in the review.

Autistic Disorder↗
PubMed2003

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Autistic Disorder↗
PubMed2002

The temporal binding deficit hypothesis of autism.

Frith has argued that people with autism show "weak central coherence," an unusual bias toward piecemeal rather than configurational processing and a reduction in the normal tendency to process information in context. However, the precise cognitive and neurological mechanisms underlying weak central coherence are still unknown. We propose the hypothesis that the features of autism associated with weak central coherence result from a reduction in the integration of specialized local neural networks in the brain caused by a deficit in temporal binding. The visuoperceptual anomalies associated with weak central coherence may be attributed to a reduction in synchronization of high-frequency gamma activity between local networks processing local features. The failure to utilize context in language processing in autism can be explained in similar terms. Temporal binding deficits could also contribute to executive dysfunction in autism and to some of the deficits in socialization and communication.

Attention↗
PubMedDate not supplied

The interactional significance of formulas in autistic language.

The phenomenon of echolalia in autistic language is well documented. Whilst much early research dismissed echolalia as merely an indicator of cognitive limitation, later work identified particular discourse functions of echolalic utterances. The work reported here extends the study of the interactional significance of echolalia to formulaic utterances. Audio and video recordings of conversations between the first author and two research participants were transcribed and analysed according to a Conversation Analysis framework and a multi-layered linguistic framework. Formulaic language was found to have predictable interactional significance within the language of an individual with autism, and the generic phenomenon of formulaicity in company with predictable discourse function was seen to hold across the research participants, regardless of cognitive ability. The implications of formulaicity in autistic language for acquisition and processing mechanisms are discussed.

Adult↗