2016 Gatlinburg Conference Poster
PS-31
Title: Stranger Fear in Preschoolers with Fragile X Syndrome and Idiopathic Autism Spectrum Disorder
Authors: Jessica Scherr, Debra Reisinger, Abigail Hogan-Brown, Jane E. Roberts
Introduction: Fragile X syndrome (FXS) is a single gene disorder associated with an increasingly well-defined phenotype
including intellectual impairment and anxiety (Cordeiro et al., 2011). In addition, traits of autism are very common in FXS with
increased impairment associated with these overlapping disorders making differential diagnosis challenging (Hagerman, 2002).
Little work has examined how anxiety features emerge in FXS or other clinical disorders. Moreover, no study has examined
behavioral observations of fear and its association with autism traits in young children with FXS from children with idiopathic
autism spectrum disorder (ASD). The early detection of specific behavioral anxiety factors that may convey groups at-risk for
anxiety is important given the impact that differential diagnosis and targeted treatments can have on changing the trajectory of
the later development of anxiety disorders. Fear of strangers has been shown to be a particularly robust predictor of the
emergence and severity of anxiety in young children (Brooker et al., 2013).
Methods: Participants consisted of 101 male preschoolers between the ages of 2-5 that were categorized into four groups: boys
with fragile X syndrome (FXS; N= 29), FXS with elevated autism symptoms (fxASD; N = 25), idiopathic autism spectrum disorder
(iASD; N = 11), and typically developing boys (TD; N = 36). Participants in each atypical group were matched on cognitive ability
by the Early Learning Composite on the Mullen Early Scales of Learning. Additionally, the fxASD and iASD groups were matched
on severity of symptoms of autism as measured by the total score on the CARS (fxASD M = 35.1, iASD M =35.0). The Stranger
Approach from the Laboratory Temperament Assessment Battery (Lab-TAB; Goldsmith & Rothbart, 1996) was used to elicit
behavioral indicators of stranger fear including gaze patterns, escape behaviors and facial fear. The Childhood Autism Rating
Scale (CARS) was used as a measure autism symptoms. Raw scores from the DSM-Anxiety subscale on the CBCL were used to
assess relationships to stranger fear.
Results: Results from one-way ANOVAs indicagte specific behavioral responses to a stranger differentiated preschoolers with
more severe symptoms of autism (e.g. fxASD and iASD groups) from those with low autism symptomology (e.g. FXS and TD
groups). Cross-group comparisons demonstrated that preschoolers with FXS displayed more avoidant gaze to the stranger and
their parent during the stranger approach with boys with fxASD exhibiting the greatest avoidant gaze patterns. The fxASD group
also referenced their parent less during the stranger approach in comparison to the FXS and TD groups. The iASD group
displayed elevated facial fear in response to the stranger that differentiated them from the FXS, fxASD, and TD groups. No group
differences were observed in escape behaviors. Overall, results from this study indicate specific behavioral patterns of social fear
in response to a stranger using a normative and cross-syndrome approach. Correlational data between CBCL and stranger fear
suggest unique patterns in each of our groups in how anxiety is expressed behaviorally.
Discussion: This is the first study to examine the early emergence of behavioral indicators of anxiety in boys with FXS and iASD.
Our use of behavioral methodology goes beyond traditional parent and self-report methods that may differentiate individuals
that are at risk for anxiety, such as those with ASD and FXS. Collectively, we have found behavioral profiles of social fear that are
both distinct, yet similar, in disorders that often overlap in symptom presentation. Clarifying these distinctions can contribute to
the refinement of differential diagnosis and treatment. It is critical to identify underlying traits that distinguish symptoms of
anxiety in ASD and FXS early in development to provide better future outcomes.