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Biomedical subjects

Susan E Bryson

Publications and source records attributed to Susan E Bryson.

12 recordsLinked to original sources
PubMed2007

Stereotyped motor behaviors associated with autism in high-risk infants: a pilot videotape analysis of a sibling sample.

This study examined motor behaviors in a longitudinal cohort of infant siblings of children with autism. Stereotypic movements and postures occurring during standardized observational assessments at 12 and 18 months were coded from videotapes. Participants included eight infant siblings later diagnosed with autism spectrum disorder (ASD), a random sample of nine non-diagnosed siblings, and 15 controls. Videos were coded blind to diagnostic group. At 12 and 18 months the ASD group "arm waved" more frequently and at 18 months, one posture ("hands to ears") was more frequently observed in the ASD and non-diagnosed group compared to the controls. Overall, the siblings subsequently diagnosed with ASD and the comparison groups had considerable overlap in their repertoires of stereotyped behaviors.

Autistic Disorder↗
PubMed2007

A prospective case series of high-risk infants who developed autism.

The present paper documents the development of autism/autistic spectrum disorder in a consecutive series of nine high-risk infants followed prospectively from 6 months of age. Evidence is provided for two broadly defined subgroups: the first subgroup (n = 6) showed a decrease in IQ between 12 and 24 or 36 months (from average/near average to severe cognitive impairment), whereas the second subgroup (n = 3) continued to obtain average or near average IQs. Signs of autism emerged and/or were more striking earlier in the first subgroup. In all nine children, early impairment in social-communicative development coexisted with atypical sensory and/or motor behaviors, as did a temperamental profile marked by irritability/distress and dysregulated state. Discussion focuses on issues raised by the pattern of findings.

Autistic Disorder↗
PubMed2005

The development of endogenous orienting: control over the scope of attention and lateral asymmetries.

This study examined the development of endogenous orienting in children ages 6, 10, and 14 years and in adults. Participants were asked to respond with a button press to targets appearing in the left or right visual field. Cues that correctly or incorrectly indicated the target's location preceded the appearance of targets at stimulus onset asynchronies (SOAs) of 100 and 800 msec. Cues that signaled a target's appearance, but not its location, were also included. In addition to raw reaction times, orienting effects, benefits, and costs were examined. Two main findings emerged: First, for all participants except the youngest children effect sizes increased with increasing SOA. The absence of an SOA effect in the youngest group is interpreted as evidence of their difficulty in voluntarily adjusting the scope of their attentional focus. In addition, field asymmetries changed with the age of the respondent: 6-year-olds showed a right-field advantage, 10-year-olds failed to show any laterality differences, and 14-year-olds and adults responded more quickly to targets in the left than in the right field. This finding is consistent with developmental data on a number of cognitive processes, and is interpreted within a developmental framework of right-hemisphere dominance for spatial orienting (cf. Mesulam, 1998).

Adolescent↗
PubMed2004

Comparing rates of psychiatric and behavior disorders in adolescents and young adults with severe intellectual disability with and without autism.

Eight males and four females with an Autism Diagnostic Interview-Revised (ADI-R) diagnosis of autism (mean age of 16.3 years) and severe intellectual disability (IQ < 40) were individually matched to controls on the basis of chronological age, gender, and nonverbal IQ. The dependent measure was the Diagnostic Assessment for the Severely Handicapped-II, which is used to screen for psychiatric and behavior disorders in lower-functioning individuals. Participants with autism showed significantly greater disturbances as measured by the Diagnostic Assessment for the Severely Handicapped-II total score and seven of 13 subscales. They also averaged 5.25 clinically significant disturbances compared with 1.25 disturbances for participants without autism. Specific vulnerabilities to anxiety, mood, sleep, organic syndromes, and stereotypies/ tics were found in the participants with comorbid autism.

Adolescent↗
PubMed2004

Specifying PDD-NOS: a comparison of PDD-NOS, Asperger syndrome, and autism.

OBJECTIVE: To describe the clinical characteristics of children given a diagnosis of pervasive developmental disorder-not otherwise specified (PDD-NOS) by expert clinicians and to compare these to the clinical characteristics of children given a diagnosis of autism and Asperger syndrome (AS). METHOD: Two hundred sixteen children with autism, 33 with AS, and 21 with PDD-NOS were compared on measures of level of functioning (communication, daily living and social skills, IQ, and age of acquisition of language) and on various symptoms of autism (impaired communication and reciprocal social interaction and a preference for repetitive and stereotyped activities). RESULTS: In terms of level of functioning measures, the PDD-NOS children had scores that were between those of the children with autism and those of the children with AS. In contrast, the PDD-NOS group had fewer autistic symptoms, especially repetitive stereotyped behaviors, than both the autism and AS groups (chi2 = 11.06, p =.004). Children with PDD-NOS could be placed into one of three subgroups: a high-functioning group (24%) who resembled AS but had transient language delay or mild cognitive impairment; a subgroup resembling autism (24%) but who had late age of onset or too severe cognitive delays or were too young to potentially meet the full diagnostic criteria for autism; and a group (52%) not fulfilling the criteria for autism because of fewer stereotyped and repetitive behaviors. CONCLUSIONS: With some revision to current diagnostic criteria, a more homogenous atypical group with significant impairments in social-communication but fewer repetitive behaviors can be differentiated from the more nonspecific PDD-NOS group. This differentiation may lead to better reliability in diagnosis and to further progress in studies of etiology.

Asperger Syndrome↗
PubMed2004

Impaired disengagement of attention in young children with autism.

BACKGROUND: The present study examined the disengage and shift operations of visual attention in young children with autism. METHODS: For this purpose, we used a simple visual orienting task that is thought to engage attention automatically. Once attention was first engaged on a central fixation stimulus, a second stimulus was presented on either side, either simultaneously or successively. Latency to begin an eye movement to the peripheral stimulus served as the main dependent measure. The two stimulus conditions (simultaneous and successive) provided independent measures of disengaging and shifting attention, respectively. Performance of children with autism was compared to that of children with Down syndrome and a normal group. RESULTS: The main finding was that relative to both comparison groups, children with autism had marked difficulty in disengaging attention. Indeed, on 20% of trials they remained fixated on the first of two competing stimuli for the entire 8-second trial duration. Evidence is also provided for a more subtle problem in executing rapid shifts of attention. CONCLUSIONS: Our findings on disengagement in autism parallel those reported in normal 2-month-olds, in whom attention has been described as 'obligatory'. Discussion focuses on the potential role of general versus domain-specific processes in producing some of the core features of autism.

Attention↗
PubMed2003

Autism spectrum disorders: early detection, intervention, education, and psychopharmacological management.

Our understanding and treatment of children with autism have changed dramatically since Leo Kanner first formally documented the disorder in 1943. With reference to the historical context, this paper reviews recent research addressing 4 major issues: early detection, intervention, education, and psychopharmacological management of children with autism and related (autistic) spectrum disorders (hereafter, "autism"). We conclude from our review of the evidence that, in the absence of additional, more compelling data, the clinical usefulness of existing screening instruments remains questionable. However, the potential importance of such research is underscored by the clear benefits of early behavioural intervention: despite differences in orientation, outcomes for children with autism can be significantly enhanced with early intensive intervention. Although many questions remain (notably, What are the critical therapeutic components? For whom? For what domains of development? For what level of intensity and duration?), interventions shown to be effective are all carefully planned, engineered, monitored, and designed to target specific skill domains. Including children with autism in regular classes within the public school system poses several challenges, the most pressing of which is the large number of school personnel who need to be trained in evidence-based teaching and behavioural management practices. Finally, psychotropic drugs may help to reduce some symptoms, but they are neither curative nor a substitute for other forms of support and intervention.

Adolescent↗
PubMed2002

The development of exogenous orienting: mechanisms of control.

The present study examined exogenous orienting in children ages 6 years (n=14), 10 years (n=13), 14 years (n=14), and adults (n=13). The main purpose was to identify which of the attentional operations underlying exogenous orienting (disengaging, shifting, and/or engaging) improves with age. A simple detection task was used in which single targets were correctly (80%) or incorrectly (20%) cued. The main finding was that disengaging attention alone distinguished the performance of younger children from that of older children and adults, regardless of whether attention alone (covert attention) or attention and associated sensory and motor systems (overt attention) were involved. In addition, our data, in contrast to those reported previously, raise the possibility that even the youngest children tested were able to use the predictability of the cue to enhance their performance. These and related neuroanatomical findings are taken as evidence for the development with age of more flexible control in orienting visual attention.

Adolescent↗
PubMed2002

Quantifying dimensions in autism: a factor-analytic study.

OBJECTIVE: The objective of this study was to determine whether the phenotypic variation in autism and the related pervasive developmental disorders (PDDs) is a unitary construct or whether it is composed of distinct dimensions of autistic symptoms and measures of level of functioning. METHOD: One hundred twenty-nine children with autism and other forms of PDD from two samples with different inclusion criteria were assessed with the Vineland Adaptive Behavior Scales to measure level of functioning and the Autism Diagnostic Interview to measure severity of autistic behaviors. A factor analysis with varimax rotation was performed on each sample, separately and combined. RESULTS: Two factors emerged; one representing autistic symptoms and another representing level of functioning. The factor structure was remarkably similar and robust to variations in ascertainment and inclusion criteria between the samples. The validity of the distinction was supported by differences between males and females on the symptom factor, but not on the level of functioning factor. IQ was modestly correlated with level of functioning, but not with symptoms. CONCLUSIONS: The phenotypic variation seen in autism/PDD is composed of at least two different dimensions of autistic symptoms and level of functioning. The implications of this dimensional heterogeneity for research, classification, and clinical practice are discussed.

Adolescent↗
PubMed2002

Pregnancy and birth complications in autism and liability to the broader autism phenotype.

OBJECTIVE: To understand better the relationship between pregnancy and birth complications and genetic factors in autism. METHOD: The sample included 78 children with an autism spectrum disorder and 88 unaffected siblings. A standardized interview was used to ask mothers about the pregnancy and birth of each child, and an overall index reflecting freedom from complications (termed "optimality") was determined. The presence of autism-like traits (termed the "broader autism phenotype") in second- and third-degree relatives was ascertained by reports from multiple informants. The pro-. portion of relatives with the broader autism phenotype, corrected for degree of relation, was used as an index of family loading. RESULTS: Children with autism spectrum disorders have lower optimality (higher rates of complications) than unaffected siblings. High family loading for the broader autism phenotype is associated with higher rates of complications in unaffected siblings. Family loading was not significantly associated with complications in affected siblings in this sample. Overall, these findings argue against complications being a direct cause of autism, as one would expect to find the most complications in sporadic cases (i.e., in children without a positive family history). CONCLUSION: Increased rates of birth and pregnancy complications are likely secondary to familial factors associated with autism.

Autistic Disorder↗
PubMed2002

Mental retardation in teenagers: prevalence data from the Niagara region, Ontario.

OBJECTIVES: There are few Canadian prevalence studies of mental retardation (MR); those that do exist were conducted prior to the era of community integration. We undertook a population-based study to explore mental health disturbances in young persons with MR. The first requirement was to identify a population with MR and to establish its prevalence. Here, we report data on the prevalence of MR in a population aged 14 to 20 years. METHOD: We conducted the study in the Niagara Region of Ontario, which has a population base of around 400,000. Researchers worked closely with schools and with agencies providing services to persons with MR to identify the study group. We confirmed the functioning level of participants through standard tests of nonverbal intelligence and receptive language; teachers and other service personnel provided information relevant to the estimation of nonparticipants' functioning level. RESULTS: We identified 255 individuals as having MR (IQ < or = 75). Of these, 171 chose to participate (defined as "participants with MR"; the remaining 84 were "nonparticipants with MR"). Thus, the participation rate was 67% (171/255). Participants and nonparticipants with MR did not differ on age, sex, or IQ, although there were more nonparticipants in the lower social strata. Overall prevalence for MR was 7.18/1000. For mild mental retardation (MMR; that is, IQ = 50 to 75), prevalence was 3.54/1000, and for severe mental retardation (SMR; that is, IQ < 50), it was 3.64/1000. CONCLUSIONS: Our prevalence estimate for SMR is similar to rates from previous studies conducted worldwide. Our estimate for MMR parallels the lower rates found in Scandinavian countries and contrasts with the higher rates generally reported in the US.

Adolescent↗