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Biomedical subjects

Simon Baron-Cohen

Publications and source records attributed to Simon Baron-Cohen.

At least 37 records · Page 2Linked to original sources
PubMed2006

The Autism-Spectrum Quotient (AQ)--adolescent version.

The Autism Spectrum Quotient (AQ) quantifies autistic traits in adults. This paper adapted the AQ for children (age 9.8-15.4 years). Three groups of participants were assessed: Group 1: n=52 adolescents with Asperger Syndrome (AS) or high-functioning autism (HFA); Group 2: n=79 adolescents with classic autism; and Group 3, n=50 controls. The adolescents with AS/HFA did not differ significantly from the adolescents with autism but both clinical groups scored higher than controls. Approximately 90% of the adolescents with AS/HFA and autism scored 30+, vs. none of the controls. Among the controls, boys scored higher than girls. The AQ can rapidly quantify where an adolescent is situated on the continuum from autism to normality.

Adolescent↗
PubMed2006

Diagnosing and phenotyping visual synaesthesia: a preliminary evaluation of the revised test of genuineness (TOG-R).

Synaesthesia, a neurological condition affecting approximately .05% of the population, is characterised by anomalous sensory perception: a stimulus in one sensory modality triggers an automatic, instantaneous, consistent response in another modality (e.g., sound evokes colour) or in a different aspect of the same modality (e.g., black text evokes colour). As evidence was limited to case studies based on self-report, the existence of synaesthesia was regarded with scepticism until the development of the Test of Genuineness (TOG) in 1987, which measures the consistency of stimulus-response linkage: synaesthetes typically score between 70-90% range, whereas controls typically score between 20-38%. However, the TOG had only limited ability to quantify the characteristics of visual synaesthesia. In this study, the revised Test of Genuineness (TOG-R), utilising the Pantone-based Cambridge Synaesthesia Charts, was given to 26 synaesthetes and 23 controls. Results confirmed that the TOG-R is equally accurate in the diagnosis of synaesthesia; synaesthetes scored significantly (t47 = 16.01, p < .001) higher (mean = 71.3%, SEM = 1.4%) than controls (mean = 33%, SEM = 2.0%). The TOG-R provides greater precision in quantifying the closeness of colour matches and enables a more detailed analysis of visual synaesthesia. Synaesthetes were phenotyped into broad- and narrowband based on their overall responsiveness to auditory stimuli, with bandwidth determined primarily by responsiveness to non-word stimuli. They were further sub-phenotyped based on responses to sub-groups of stimuli into word-colour (WC) and music-colour (MC). Development of this instrument has important implications for the diagnosis and phenotyping of visual synaesthesia.

Adult↗
PubMed2006

Empathizing: neurocognitive developmental mechanisms and individual differences.

This chapter reviews the Mindreading System model encompassing four neurocognitive mechanisms (ID, EDD, SAM, and ToMM) before reviewing the revised empathizing model encompassing two new neurocognitive mechanisms (TED and TESS). It is argued that the empathizing model is more comprehensive because it entails perception, interpretation, and affective responses to other agents. Sex differences in empathy (female advantage) are then reviewed, as a clear example of individual differences in empathy. This leads into an illustration of individual differences using the Empathy Quotient (EQ). Finally, the neuroimaging literature in relation to each of the neurocognitive mechanisms is briefly summarized and a new study is described that tests if different brain regions respond to the perception of different facial expressions of emotion, as a function of the observer's EQ.

Brain↗
PubMed2006

Systemizing empathy: teaching adults with Asperger syndrome or high-functioning autism to recognize complex emotions using interactive multimedia.

This study evaluated Mind Reading, an interactive systematic guide to emotions, for its effectiveness in teaching adults with Asperger syndrome (AS) and high-functioning autism (HFA) to recognize complex emotions in faces and voices. Experiment 1 tested a group of adults diagnosed with AS/HFA (n = 19) who used the software at home for 10-15 weeks. Participants were tested on recognition of faces and voices at three different levels of generalization. A matched control group of adults with AS/HFA (n = 22) were assessed without any intervention. In addition, a third group of general population controls (n = 24) was tested. Experiment 2 repeated the design of Experiment 1 with a group of adults with AS/HFA who used the software at home and met in a group with a tutor on a weekly basis. They were matched to a control group of adults with AS/HFA attending social skills training and to a general population control group (n = 13 for all three groups). In both experiments the intervention group improved significantly more than the control group on close, but not distant, generalization tasks. Verbal IQ had significant effects in Experiment 2. Using Mind Reading for a relatively short period of time allows users to learn to recognize a variety of complex emotions and mental states. However, additional methods are required to enhance generalization.

Adolescent↗
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

Phenotypic and genetic overlap between autistic traits at the extremes of the general population.

OBJECTIVE: To investigate children selected from a community sample for showing extreme autistic-like traits and to assess the degree to which these individual traits--social impairments (SIs), communication impairments (CIs), and restricted repetitive behaviors and interests (RRBIs)--are caused by genes and environments, whether all of them are caused by the same genes and environments, and how often they occur together (as required by an autism diagnosis). METHOD: The most extreme-scoring 5% were selected from 3,419 8-year-old pairs in the Twins Early Development Study assessed on the Childhood Asperger Syndrome Test. Phenotypic associations between extreme traits were compared with associations among the full-scale scores. Genetic associations between extreme traits were quantified using bivariate DeFries-Fulker extremes analysis. RESULTS: Phenotypic relationships between extreme SIs, CIs, and RRBIs were modest. There was a degree of genetic overlap between them, but also substantial genetic specificity. CONCLUSIONS: This first twin study assessing the links between extreme individual autistic-like traits (SIs, CIs, and RRBIs) found that all are highly heritable but show modest phenotypic and genetic overlap. This finding concurs with that of an earlier study from the same cohort that showed that a total autistic symptoms score at the extreme showed high heritability and that SIs, CIs, and RRBIs show weak links in the general population. This new finding has relevance for both clinical models and future molecular genetic studies.

Autistic Disorder↗
PubMed2006

Variations in the human cannabinoid receptor (CNR1) gene modulate striatal responses to happy faces.

Happy facial expressions are innate social rewards and evoke a response in the striatum, a region known for its role in reward processing in rats, primates and humans. The cannabinoid receptor 1 (CNR1) is the best-characterized molecule of the endocannabinoid system, involved in processing rewards. We hypothesized that genetic variation in human CNR1 gene would predict differences in the striatal response to happy faces. In a 3T functional magnetic resonance imaging (fMRI) scanning study on 19 Caucasian volunteers, we report that four single nucleotide polymorphisms (SNPs) in the CNR1 locus modulate differential striatal response to happy but not to disgust faces. This suggests a role for the variations of the CNR1 gene in underlying social reward responsivity. Future studies should aim to replicate this finding with a balanced design in a larger sample, but these preliminary results suggest neural responsivity to emotional and socially rewarding stimuli varies as a function of CNR1 genotype. This has implications for medical conditions involving hypo-responsivity to emotional and social stimuli, such as autism.

Brain Mapping↗
PubMed2006

The development of siblings of children with autism at 4 and 14 months: social engagement, communication, and cognition.

AIMS: To compare siblings of children with autism (SIBS-A) and siblings of children with typical development (SIBS-TD) at 4 and 14 months of age. METHODS: At 4 months, mother-infant interactional synchrony during free play, infant gaze and affect during the still-face paradigm, and infant responsiveness to a name-calling paradigm were examined (n = 21 in each group). At 14 months, verbal and nonverbal communication skills were examined as well as cognition (30 SIBS-A and 31 SIBS-TD). RESULTS: Most SIBS-A were functioning as well as the SIBS-TD at 4 and 14 months of age. However, some differences in early social engagement and later communicative and cognitive skills emerged. Synchrony was weaker in the SIBS-A dyads, but only for infant-led interactions. Infant SIBS-A revealed more neutral affect during the still-face procedure and were less upset by it than was true for the SIBS-TD. A surprising result was that significantly more SIBS-A responded to their name being called by their mothers compared to SIBS-TD. At 14 months, SIBS-A made fewer nonverbal requesting gestures and achieved lower language scores on the Bayley Scale. Six SIBS-A revealed a language delay of 5 months and were responsible for some of the significant differences between SIBS-A and SIBS-TD. Furthermore, infant SIBS-A who showed more neutral affect to the still face and were less able to respond to their name being called by their mothers initiated fewer nonverbal joint attention and requesting behaviors at 14 months, respectively. DISCUSSION: Focused on the genetic liability for the broad phenotype of autism as well as the possible influence of having a sibling with autism.

Age Factors↗
PubMed2006

Can Asperger syndrome be diagnosed at 26 months old? A genetic high-risk single-case study.

Asperger syndrome, a heritable condition entailing empathy deficits together with unusually narrow interests in individuals of normal or even above-average intelligence, was recognized only recently. Here we report the first-ever prospective study of a child born to two adults with a formal diagnosis of Asperger syndrome. The child's parents are both scientists (a mathematician and a chemist). The aim of study 1 was to test if the child also developed Asperger syndrome, given the heritability of the condition, and if Asperger syndrome can be detected at 26 months. At 18 months, the child was given the Checklist for Autism in Toddlers, and at 26 months, she was assessed diagnostically for autism spectrum conditions using the Autism Diagnostic Interview-Revised and the Autism Diagnostic Observational Scale. The child failed the Checklist for Autism in Toddlers at 18 months and met the criteria for Asperger syndrome at 26 months. This single case is consistent with the hypersystemizing, assortative mating theory of autism. This theory requires further testing with large samples. This study also demonstrates that Asperger syndrome can be diagnosed by age 26 months. The aim of study 2 was to test if dyadic eye contact in infancy is intact in a child later diagnosed with Asperger syndrome. The same child's eye contact was measured at three time points (3, 6, and 9 months) over her first year of life and compared with that of age-matched controls. Although the child had low rates of eye contact at 6 months, it was within the normal range at all three points in the first year of life. We conclude that low levels of eye contact are not predictive of later development of Asperger syndrome.

Age Factors↗
PubMed2006

Fetal testosterone and sex differences in typical social development and in autism.

Experiments in animals leave no doubt that androgens, including testosterone, produced by the testes in fetal and/or neonatal life act on the brain to induce sex differences in neural structure and function. In human beings, there is evidence supporting a female superiority in the ability to read nonverbal signals, specific language-related skills, and theory of mind. Even more striking than the sex differences seen in the typical population is the elevated occurrence of social and communicative difficulties in human males. One such condition, autism, occurs four times more frequently in boys than in girls. Recently, a novel theory known as the "extreme male brain" has been proposed. It suggests that the behaviors seen in autism are an exaggeration of typical sex differences and that exposure to high levels of prenatal testosterone might be a risk factor. In this article, we argue that prenatal and neonatal testosterone exposures are strong candidates for having a causal role in sexual dimorphism in human behavior, including social development, and as risk factors for conditions characterized by social impairments, particularly autism spectrum conditions.

Animals↗
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

[Individual and gender differences in Empathizing and Systemizing: measurement of individual differences by the Empathy Quotient (EQ) and the Systemizing Quotient (SQ)].

Empathizing is a drive to identify another person's emotions and thoughts and respond to them appropriately. Systemizing is a drive to analyze systems or construct systems. The Empathizing-Systemizing (E-S) model suggests that these are major dimensions in which individuals differ from each other, and women being superior in empathizing and men in systemizing. In this study, we examined new questionnaires, the Empathy Quotient (EQ) and the Systemizing Quotient (SQ). Participants were 1 250 students, 616 men and 634 women, from eight universities, who completed both the EQ and SQ. Results showed that women scored higher than men on the EQ, and the result was reversed on the SQ. Results also showed that humanities majors scored higher than sciences majors on the EQ, and again the result was reversed on the SQ. The results were discussed in relation to the E-S theory of gender differences.

Adult↗
PubMed2005

Sex differences in the brain: implications for explaining autism.

Empathizing is the capacity to predict and to respond to the behavior of agents (usually people) by inferring their mental states and responding to these with an appropriate emotion. Systemizing is the capacity to predict and to respond to the behavior of nonagentive deterministic systems by analyzing input-operation-output relations and inferring the rules that govern such systems. At a population level, females are stronger empathizers and males are stronger systemizers. The "extreme male brain" theory posits that autism represents an extreme of the male pattern (impaired empathizing and enhanced systemizing). Here we suggest that specific aspects of autistic neuroanatomy may also be extremes of typical male neuroanatomy.

Androgens↗
PubMed2005

Fetal testosterone and empathy.

BACKGROUND: In animals, fetal testosterone (fT) plays a central role in organizing the brain and in later social behavior. In humans, exposure to atypical levels of prenatal androgens may result in masculine behavior and ability patterns. Normal inter-individual variation in fT levels has also been correlated with later sex-typed behavior. METHODS: In the current study, 38 children (24 male, 14 female), whose fT was analyzed in amniotic fluid, were followed up at age 4. They were asked to describe cartoons with 2 moving triangles whose interactions with each other suggested social relationships and psychological motivations. RESULTS: Females used more mental and affective state terms to describe the cartoons than males. fT was not associated with the frequency of mental or affective state terms. Females also used more intentional propositions than males. fT was negatively correlated with the frequency of intentional propositions, taking sex differences into account. fT was also negatively correlated with the frequency of intentional propositions when males were examined separately. Males used more neutral propositions than females. fT was directly correlated with the frequency of neutral propositions, taking sex differences into account. This relationship was not seen when males and females were examined separately. CONCLUSIONS: These findings implicate fT in human social development. The relevance of our findings to the 'extreme male brain' theory of autism is also discussed.

Affect↗
PubMed2005

Change detection in children with autism: an auditory event-related fMRI study.

Autism involves impairments in communication and social interaction, as well as high levels of repetitive, stereotypic, and ritualistic behaviours, and extreme resistance to change. This latter dimension, whilst required for a diagnosis, has received less research attention. We hypothesise that this extreme resistance to change in autism is rooted in atypical processing of unexpected stimuli. We tested this using auditory event-related fMRI to determine regional brain activity associated with passive detection of infrequently occurring frequency-deviant and complex novel sounds in a no-task condition. Participants were twelve 10- to 15-year-old children with autism and a group of 12 age- and sex-matched healthy controls. During deviance detection, significant activation common to both groups was located in the superior temporal and inferior frontal gyri. During 'novelty detection', both groups showed activity in the superior temporal gyrus, the temporo-parietal junction, the superior and inferior frontal gyri, and the cingulate gyrus. Children with autism showed reduced activation of the left anterior cingulate cortex during both deviance and novelty detection. During novelty detection, children with autism also showed reduced activation in the bilateral temporo-parietal region and in the right inferior and middle frontal areas. This study confirms previous evidence from ERP studies of atypical brain function related to automatic change detection in autism. Abnormalities involved a cortical network known to have a role in attention switching and attentional resource distribution. These results throw light on the neurophysiological processes underlying autistic 'resistance to change'.

Acoustic Stimulation↗
PubMed2005

Functional disconnectivity of the medial temporal lobe in Asperger's syndrome.

BACKGROUND: Autistic spectrum disorders (ASD) are neurodevelopmental conditions that may be caused by abnormal connectivity between brain regions constituting neurocognitive networks for specific aspects of social cognition. METHODS: We used three-way multidimensional scaling of regionally parcellated functional magnetic resonance imaging (fMRI) data to explore the hypothesis of abnormal functional connectivity in people with ASD. Thirteen high-functioning individuals with Asperger's syndrome and 13 healthy volunteers were scanned during incidental processing of fearful facial expressions. RESULTS: Using permutation tests for inference, we found evidence for significant abnormality of functional integration of amygdala and parahippocampal gyrus (p < .05, false discovery rate [FDR] corrected) in people with Asperger's syndrome. There were less salient abnormalities in functional connectivity of anterior cingulate, inferior occipital, and inferior frontal cortex, but there was no significant difference between groups in whole brain functional connectivity. CONCLUSIONS: We conclude there is evidence that functional connectivity of medial temporal lobe structures specifically is abnormal in people with Asperger's syndrome during fearful face processing.

Adult↗