Date of Award

Summer 2022

Document Type

Open Access Thesis



First Advisor

Jane Roberts


Proficient sensory processing affords adaptive responses that are necessary for daily functioning. Atypical sensory processing patterns are common across neurodevelopmental disorders, including autism spectrum disorder (ASD) and fragile X syndrome (FXS), two disorders with a high degree of phenotypic overlap. However, little is known about whether types of atypical sensory processing in FXS vary as a function of genetic etiology or the presence of ASD. Atypical sensory processing has been also associated with maladaptive outcomes in certain clinical populations; however, the impact of these impairments on internalizing and externalizing behavior remains unknown in FXS. Study participants included 37 male children with idiopathic ASD (iASD; chronological ageM (CAM)=45.30; nonverbal mental ageM (NVMAM)=28.73) and 35 male children with FXS. The FXS group included 20 children with comorbid FXS+ASD (FXS+ASD; CAM=50.20.; NVMAM=19.90) and 15 children with FXS who do not have ASD (FXS-only CAM=45.60.; NVMAM=28.27). Results comparing sensory profiles across groups indicated that there were significant group differences across all domains of sensory processing controlling for nonverbal mental age (NVMA). Specifically, ASD groups were similar on hypo-responsivity and sensory seeking and FXS groups were similar on hyper-responsivity and sensory seeking. The associations between types of atypical sensory processing and broadband ratings of internalizing and externalizing behavior were relatively comparable across group; however, phenotypic specificity did emerge for children with FXS-only. Findings have implications for potential etiological mechanisms of sensory processing difficulties and their functional consequences for individuals with iASD, FXS+ASD, and FXS-only. Implications for diagnostic specificity, targeted assessment, and intervention are discussed.


© 2022, Chandler Knott

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