19953
Examining Patterns of Restricted and Repetitive Behaviors in Angelman Syndrome and Idiopathic Autism Using the Behavior and Sensory Interests Questionnaire
Sensory interests and repetitive behaviors (RRBs) are a diagnostic feature of Idiopathic Autism Spectrum Disorders (I-ASD) and have been clinically reported in Angelman Syndrome (AS). Past research has shown that RRBs in I-ASD can have negative impacts on outcomes for individuals and their families (Gabriels et. al, 2004). Additionally, the literature evaluating RRBs in autism spectrum disorders has suggested that two subdomains of RRBs, repetitive sensorimotor (RSM) and insistence on sameness (IS), may be distinct in presentation and have shown to be correlated with ratio Intelligence Quotient (IQ). The literature also suggests that these subdomains should be evaluated separately, rather than lumped as RRBs (Richler et. al, 2010). There has been one previous study reporting on a limited selection of RRBs in the AS population (Walz, 2007), and none comparing the type and rate of these behaviors between I-ASD and AS populations.
Objectives:
This study examines the type of RRB’s and the expression of IS and RSM subdomains with regard to ratio IQ in two cohorts of AS and I-ASD individuals, using the Behavior and Sensory Interest Questionnaire (BSIQ).
Methods:
The I-ASD cohort consisted of 87 children (65 male) between 36-213 months (M=106, SD=52) and IQ range between 4-69 IQ (M=41, SD=17) with I-ASD from the Boston cohort of the Simons Simplex Collection and the Boston Autism Consortium
The AS cohort consisted of 152 children with AS (77 male) between 36-209 months (M=84, SD=42) and 4-69 IQ (M=26, SD=15)from the Angelman Syndrome NIH RDCRN consortium.
Measures:
The Ever and Current codes on the BSIQ, a newly standardized, parent interview measure (Hanson et. al, submitted) were used to evaluate RRBs. The Bayley Scales of Infant Development II (AS), the Mullen Scales of Early Learning, or the Differential Ability Scales (I-ASD) depending on age and level of cognitive function were used to determine ratio IQ scores. Additionally, the Vineland Adaptive Behavior Scales II was used to evaluate co-occurrence of adaptive behaviors.
Analyses:
Kruskal-Wallis and Wilcoxon rank sum tests with Bonferroni correction, ANCOVA and Spearman’s rank correlations were used to compare RRB patterns in the I-ASD and AS groups.
Results:
IQ was inversely correlated with RSM and RRBs in AS and was not correlated with IS in AS nor RSM, IS, or RRBs in I-ASD. Overall the I-ASD cohort exhibited a greater rate of RRBs than the AS cohort and the greatest discrepancy occurred in the IS subdomain. Ongoing analyses focus on evaluation of intensity and type of RRBs observed.
Conclusions:
While RRBs are a defining feature of both diagnostic groups, analyses showed that RSM, IS, and total RRBs are significantly more prevalent in I-ASD than in AS. The difference is significant in all but the <10 IQ bin. Our findings of significantly lower prevalence of IS behaviors in AS in comparison to I-ASD supports the suggestion of previous literature that IS and RSM behaviors should be evaluated as distinct domains. It also suggested that IS behaviors could be characteristic of I-ASD and that RSM behaviors are more broadly seen.