Andrea McDuffie

Autism spectrum disorder in children and adolescents with fragile X syndrome: within-syndrome differences and age-related changes.

The Autism Diagnostic Interview-Revised (ADI-R) was used to examine diagnostic profiles and age-related changes in autism symptoms for a group of verbal children and adolescents who had fragile X syndrome, with and without autism. After controlling for nonverbal IQ, we found statistically significant between-group differences for lifetime and current autism symptoms for the Communication and Restricted Interests/Repetitive Behaviors domains, but not the Reciprocal Social Interaction domain. Effect sizes for differences in Reciprocal Social Interaction also were smaller than effect sizes for the other domains, with one exception. Overall, severity of autism symptoms improved with age for all participants, with the least improvement noted for Restricted Interests and Repetitive Behaviors. FMRP did not account for unique variance in autism symptoms over and above nonverbal IQ.

Getting the point: electrophysiological correlates of protodeclarative pointing

We examined the longitudinal relationships between power data in two bands (i.e. 4–6 and 6–9 Hz) of electrical activity in the brain at 14 months, as measured by background electroencephalograms (EEG), with protodeclarative and protoimperative pointing at 18 months, as measured by the Early Social Communication Scales (ESCS), [Mundy et al., ESCS: A Preliminary Manual for the Abridged Early Social Communication Scales, 1996, unpublished manual] (n=27). EEGs were recorded from 64 sensors using the Electrical Geodesics (EGI) systems dense array sensor nets. Multivariate permutation testing (MPT), which controlled for experiment‐wise error due to multiple significance tests, revealed significant correlations between log‐transformed power in the frontal region at 14 months and protodeclarative, but not protoimperative, pointing at 18 months.

The fragile X syndrome-autism comorbidity: what do we really know?

Autism spectrum disorder (ASD) is a common comorbid condition in people with fragile X syndrome (FXS). It has been assumed that ASD symptoms reflect the same underlying psychological and neurobiological impairments in both FXS and non-syndromic ASD, which has led to the claim that targeted pharmaceutical treatments that are efficacious for core symptoms of FXS are likely to be beneficial for non-syndromic ASD as well. In contrast, we present evidence from a variety of sources suggesting that there are important differences in ASD symptoms, behavioral and psychiatric correlates, and developmental trajectories between individuals with comorbid FXS and ASD and those with non-syndromic ASD. We also present evidence suggesting that social impairments may not distinguish individuals with FXS with and without ASD. Finally, we present data that demonstrate that the neurobiological substrates of the behavioral impairments, including those reflecting core ASD symptoms, are different in FXS and non-syndromic ASD. Together, these data suggest that there are clinically important differences between FXS and non-syndromic ASD that are masked by reliance on the categorical diagnosis of ASD. We argue for use of a symptom-based approach in future research, including studies designed to evaluate treatment efficacy.

Increasing verbal responsiveness in parents of children with autism:a pilot study:

Correlational studies have revealed a positive relationship between parent verbal responsiveness and language outcomes in children with autism. We investigated whether parents of young children on the autism spectrum could learn and implement the specific categories of verbal responsiveness that have been suggested to facilitate language development. Parents were taught to increase their verbal responsiveness in the context of a short-term language intervention that included group parent education sessions, as well as individual and small-group coaching sessions of parent–child play interactions. Parents in the treatment group increased their use of comments that: described their child’s focus of attention; interpreted or expanded child communication acts; and prompted child communication. Preliminary treatment effects were also noted in children’s prompted and spontaneous communication. These results support the use of parent-mediated interventions targeting verbal responsiveness to facilitate language development and communication in young children with autism.

Profiles of Receptive and Expressive Language Abilities in Boys With Comorbid Fragile X Syndrome and Autism

Abstract The authors examined receptive and expressive language profiles for a group of verbal male children and adolescents who had fragile X syndrome along with varying degrees of autism symptoms. A categorical approach for assigning autism diagnostic classification, based on the combined use of the Autism Diagnostic Interview-Revised and the Autism Diagnostic Observation Schedule (ADOS), and a continuous approach for representing autism symptom severity, based on ADOS severity scores, were used in 2 separate sets of analyses. All analyses controlled for nonverbal IQ and chronological age. Nonverbal IQ accounted for significant variance in all language outcomes with large effect sizes. Results of the categorical analyses failed to reveal an effect of diagnostic group (fragile X syndrome-autism, fragile X syndrome-no autism) on standardized language test performance. Results of the continuous analyses revealed a negative relationship between autism symptom severity and all of the standardized language measures. Implications for representing autism symptoms in fragile X syndrome research are considered.

Symptoms of Autism in Males with Fragile X Syndrome: A Comparison to Nonsyndromic ASD Using Current ADI-R Scores.

Symptoms of autism are frequent in males with fragile X syndrome (FXS), but it is not clear whether symptom profiles differ from those of nonsyndromic ASD. Using individual item scores from the Autism Diagnostic Inventory-Revised, we examined which current symptoms of autism differed in boys with FXS relative to same-aged boys diagnosed with nonsyndromic ASD. In addition, different subsamples of participants were matched on autism diagnostic status and severity of autism symptoms. Between-group comparisons revealed that boys with FXS showed significantly less impairment in Social Smiling than did age-, diagnostic-, and severity-matched boys with nonsyndromic ASD. Severity-matched boys with FXS showed more impairment in complex mannerisms than did boys with nonsyndromic ASD. Behavioral differences between FXS and nonsyndromic ASD may be of theoretical importance in understanding the causes and correlates of ASD in FXS and in developing and implementing appropriate treatments.

Fast-mapping in young children with autism spectrum disorders

A longitudinal correlational design was used to examine whether fast-mapping mediates the relationship between attention-following and vocabulary size in a group of 29 young children diagnosed with autism spectrum disorders. Attention-following was measured at the initial visit. Fast-mapping as well as comprehension and production of noun vocabulary were measured six months later. Attention-following had a significant predictive association with fast-mapping and with both vocabulary outcomes. Fast-mapping had a significant concurrent association with vocabulary and met all the criteria for mediating the association between attention-following and the number of nouns children understood and said at the follow-up. These findings support the value of targeting attention-following to increase word learning for children with ASD.

Psychiatric symptoms in boys with fragile X syndrome: A comparison with nonsyndromic autism spectrum disorder

In the present study, we examined the profile of psychiatric symptoms in boys with fragile X syndrome (FXS) using a parent report instrument. In addition, by comparing boys with FXS to boys with nonsyndromic autism spectrum disorder (ASD) utilizing multiple matching strategies, we examined between-group differences in the types of psychiatric symptoms observed and in the strength of their concurrent associations. Across all matching strategies, symptoms of manic/hyperactive behaviors and general anxiety were more frequently reported for boys with FXS than for boys with nonsyndromic ASD. Results also indicated a positive association between social avoidance and general anxiety in FXS that was stronger than that observed in nonsyndromic ASD across all matching strategies. Theoretical and treatment implications are discussed.

A comparison of contexts for assessing joint attention in toddlers on the autism spectrum

Children on the autism spectrum often demonstrate atypical joint attention, leading some researchers to consider joint attention defecits a core feature of the autism spectrum. Structured measures, such as the Early Social Communication Scales (ESCS), are commonly used to provide a metric of joint attention. To explore the assessment of joint attention in multiple contexts, we implemented an alternative system for coding joint attention behaviors. We compared initiation of joint attention (IJA) and response to joint attention (RJA) behaviors coded from naturalistic examiner—child play samples with similar IJA and RJA behaviors elicited within the structured ESCS protocol. Participants were 20 toddlers on the autism spectrum. Levels of IJA and RJA within the two assessment contexts were significantly and positively correlated, providing support for the use of naturalistic sampling of joint attention skills as a viable alternative, or supplement, to structured measures.

Labels increase attention to novel objects in children with autism and comprehension-matched children with typical development

This study used an intact group comparison to examine attention following in 34 children aged 2 years diagnosed with autism spectrum disorder (ASD) matched pairwise for vocabulary comprehension with a group of typically developing toddlers. For both groups of children, the presence of verbal labels during a referential task increased attention to a novel object over and above the attention-facilitating effect of child-directed talking without labeling.The typically developing children displayed more attention following than comprehension matched children with ASD across experimental conditions and there was no significant difference between the groups in the facilitative effect of hearing verbal labels. Implications for word-learning theory, intervention strategies and future research are considered.