Bruce J. Tonge

Intranasal Oxytocin Improves Emotion Recognition for Youth with Autism Spectrum Disorders

BACKGROUND A diagnostic hallmark of autism spectrum disorders is a qualitative impairment in social communication and interaction. Deficits in the ability to recognize the emotions of others are believed to contribute to this. There is currently no effective treatment for these problems. METHODS In a double-blind, randomized, placebo-controlled, crossover design, we administered oxytocin nasal spray (18 or 24 IU) or a placebo to 16 male youth aged 12 to 19 who were diagnosed with Autistic or Aspergers Disorder. Participants then completed the Reading the Mind in the Eyes Task, a widely used and reliable test of emotion recognition. RESULTS In comparison with placebo, oxytocin administration improved performance on the Reading the Mind in the Eyes Task. This effect was also shown when analysis was restricted to the younger participants aged 12 to 15 who received the lower dose. CONCLUSIONS This study provides the first evidence that oxytocin nasal spray improves emotion recognition in young people diagnosed with autism spectrum disorders. Findings suggest the potential of earlier intervention and further evaluation of oxytocin nasal spray as a treatment to improve social communication and interaction in young people with autism spectrum disorders.

The Developmental Behavior Checklist: the development and validation of an instrument to assess behavioral and emotional disturbance in children and adolescents with mental retardation.

Describes the development and validation of the Developmental Behavior Checklist (DBC), a standardized instrument completed by lay informants to assess behavioral and emotional disturbance in children and adolescents with mental retardation (MR). Items describing common behavioral and emotional problems in this population were generated by extracting descriptions from 664 case files of children and adolescents with behavior disorders seen at a specialist developmental assessment service over 12 years. These items were reduced to a set of 96 items administered to a sample of 1,093 children and adolescents with mental retardation and then submitted to a principal components analysis. Six interpretable and partly validated subscales were obtained which explained 36% of the total variance and had satisfactory internal consistency. Interrater and testretest agreement were satisfactory for both total scale score and for scores on each of the subscales. Good evidence of concurrent validity was provided by substantial positive correlations between total scores on the DBC completed by lay informants and the ratings of experienced psychiatrists based upon interviews and scores on two standardized instruments that must be completed by health professionals. The discriminative validity of the total score as assessed by area under the ROC curve was excellent (92%). Standardized norms for the DBC are derived from an epidemiological study of behavior problems in children and adolescents with mental retardation undertaken in two Australian States. Norms are available for the mild, moderate, severe, and profound MR groups and for the MR population as a whole.

An investigation into sleep characteristics of children with autism and Asperger’s Disorder

The aim of the study was to investigate the specificity of sleep problems in children with autism and further explore the currently unclear association between sleep problems and daytime behaviour.

Movement preparation in high-functioning autism and Asperger disorder: a serial choice reaction time task involving motor reprogramming.

Autism and Asperger disorder have long been associated with movement abnormalities, although the neurobehavioural details of these abnormalities remain poorly defined. Clumsiness has traditionally been associated with Asperger disorder but not autism, although this is controversial. Others have suggested that both groups demonstrate a similar global motor delay. In this study we aimed to determine whether movement preparation or movement execution was atypical in these disorders and to describe any differences between autism and Asperger disorder. A simple motor reprogramming task was employed. The results indicated that individuals with autism and Asperger disorder have atypical movement preparation with an intact ability to execute movement. An atypical deficit in motor preparation was found in Asperger disorder, whereas movement preparation was characterized by a “lack of anticipation” in autism. The differences in movement preparation profiles in these disorders were suggested to reflect differential involvement of the fronto-striatal region, in particular the supplementary motor area and anterior cingulate.

Interpersonal motor resonance in autism spectrum disorder: evidence against a global "mirror system" deficit.

The mirror neuron hypothesis of autism is highly controversial, in part because there are conflicting reports as to whether putative indices of mirror system activity are actually deficient in autism spectrum disorder (ASD). Recent evidence suggests that a typical putative mirror system response may be seen in people with an ASD when there is a degree of social relevance to the visual stimuli used to elicit that response. Individuals with ASD (n = 32) and matched neurotypical controls (n = 32) completed a transcranial magnetic stimulation (TMS) experiment in which the left primary motor cortex (M1) was stimulated during the observation of static hands, individual (i.e., one person) hand actions, and interactive (i.e., two person) hand actions. Motor-evoked potentials (MEP) were recorded from the contralateral first dorsal interosseous, and used to generate an index of interpersonal motor resonance (IMR; a putative measure of mirror system activity) during action observation. There was no difference between ASD and NT groups in the level of IMR during the observation of these actions. These findings provide evidence against a global mirror system deficit in ASD, and this evidence appears to extend beyond stimuli that have social relevance. Attentional and visual processing influences may be important for understanding the apparent role of IMR in the pathophysiology of ASD.

Behavioral and Emotional Disturbance in Individuals With Williams Syndrome

Behavioral and emotional disturbance was assessed in 70 children and adolescents with Williams syndrome. They were compared with an epidemiological control population, which was statistically controlled for age, gender, and level of mental retardation. Those with Williams syndrome were more likely to be diagnosed as suffering psychiatric disorder. The disorder was characterized by anxiety, hyperactivity, preoccupations, and inappropriate interpersonal relating. Significantly increased rates of other individual symptoms were also found, including sleep disturbance and hyperacusis. These results, considered with earlier findings, suggest that there is a valid behavior phenotype of Williams syndrome. This is frequently associated with sufficient impairment to consider inclusion of the behavior phenotype in future official taxonomies of mental disorders.

A Deficit in Shifting Attention Present in High-Functioning Autism but not Asperger’s Disorder:

The aim of this study was to examine executive functioning, in particular, attentional set-shifting deficits in high-functioning autism (n = 12) and Asperger’s disorder (n = 12). A large or global digit composed of smaller or local digits was presented during each trial. The participants indicated the presence of 1s or 2s by pressing the appropriate button. These targets could appear globally or locally. Relative to IQ, sex and age matched controls, reaction time to global targets in individuals with autism was retarded when the previous target appeared locally. This deficiency in shifting from local to global processing, however, was not observed in individuals with Asperger’s disorder. The theoretical and neurobiological significance of this dissociation in executive functioning in these clinically related disorders was explored.

Behavioural and Emotional Disturbance in High-Functioning Autism and Asperger Syndrome

This study aimed to determine whether there were differences in behavioural and emotional disturbance (psychopathology) between children and adolescents with high-functioning autism and Asperger syndrome. Subjects consisted of 75 children and adolescents with high-functioning autism and 52 with Aspergers disorder (DSM-IV diagnoses). Psychopathology was measured using the Developmental Behaviour Checklist. Analysis of covariance (ANCOVA) controlling for the effects of age and cognitive level was used to determine whether the groups differed in their levels of psychopathology. It was found that children and adolescents with Aspergers disorder presented with higher levels of psychopathology than those with high-functioning autism, were more disruptive, antisocial and anxious, and had more problems with social relationships. The implications of these findings are discussed.

Gait function in newly diagnosed children with autism: Cerebellar and basal ganglia related motor disorder.

We investigated gait in newly diagnosed children with autism. From our previous study with 6- to 14-year-olds, we hypothesized that motor symptoms indicative of basal ganglia and cerebellar dysfunction would appear across the developmental trajectory of autism. Two groups were recruited: children with autism (eight males, three females; mean age 5 y 10 mo [SD 9 mo]; range 4 y 4 mo-6 y 9 mo) and a comparison group of typically developing children (eight males, three females; mean age 5 y 9 mo [SD 1 y 1 mo]; range 4 y 3 mo-7 y 2 mo). The GAITRite Walkway was used to gather data from average gait and intra-walk measurements. Experienced physiotherapists analyzed gait qualitatively. Groups were matched according to age, height, weight, and IQ; although not statistically significant, IQ was lower in the group with autism. Spatiotemporal gait data for children with autism were compatible with findings from patients with cerebellar ataxia: specifically, greater difficulty walking along a straight line, and the coexistence of variable stride length and duration. Children with autism were also less coordinated and rated as more variable and inconsistent (i.e. reduced smoothness) relative to the comparison group. Postural abnormalities in the head and trunk suggest additional involvement of the fronto-striatal basal ganglia region. Abnormal gait features are stable across key developmental periods and are, therefore, promising for use in clinical screening for autism.

Autism and ADHD: How far have we come in the comorbidity debate?

The potential for the coexistence of the developmental disorders autism and attention-deficit/hyperactivity disorder (ADHD) in any one individual has for a long time been a contentious issue. While from a neurobiological perspective it is possible, and even highly likely, that ADHD and autism might clinically co-exist, our major diagnostic classification systems (DSM-IV-TR and ICD-10) currently preclude such a dual-diagnosis. The aim of the current review is to summarise current diagnostic criteria and treatment strategies for the two disorders, relevant theories of developmental dysfunction, and update the state of the debate regarding comorbidity. Evidence from clinical, neuroimaging and neuropsychological domains is considered, and similarities and differences between the two disorders are identified. Suggestions for future research into the comorbid profiles of these disorders are proposed, with a strong emphasis placed on the neuropsychological assessment of executive functioning as a potentially useful tool for both identifying similarities, and differentiating the disorders.