Dissertations, Theses, and Capstone Projects

Date of Degree

9-2025

Document Type

Doctoral Dissertation

Degree Name

Doctor of Philosophy

Program

Psychology

Advisor

Veronica J. Hinton

Committee Members

Sarah O'Neill

Carolyn Pytte

Emily Graves Allen

Jessica E. Hunter

Subject Categories

Cognitive Psychology | Developmental Psychology

Keywords

Attention Network Test, intrasubject variability, neuropsychological assessment, executive functioning, reaction time, females with a fragile x premutation

Abstract

The fragile X premutation (PM), characterized by 55 to 200 CGG repeats in the FMR1 gene, is associated with diverse clinical outcomes, including cognitive and neuropsychiatric changes. Despite most individuals with a PM presenting without overt clinical symptoms, adults face increased risks for conditions associated with a PM, including higher rates of attention and executive difficulties. This dissertation investigates the developmental trajectory of attention and executive functioning changes in females with a PM using a series of prospective studies employing the Attention Network Test (ANT). Study 1 re-analyzed prior data on sustained attention in women with a PM, revealing significant associations between self-reported executive difficulties and intrasubject reaction time (RT) variability, emphasizing the sensitivity of this measure in detecting subtle cognitive impairments. Study 2 examined children with a PM, finding no significant differences in attention or executive functioning compared to noncarriers, suggesting that these deficits may not manifest during childhood. In contrast, Study 3 demonstrated greater RT variability and executive control difficulties in women compared to girls with a PM. The findings suggest that attentional and executive difficulties may emerge or intensify with age, potentially driven by PM-related neurobiological mechanisms. These studies underscore the importance of longitudinal research to confirm developmental trajectories and inform early intervention strategies, ultimately advancing clinical care and understanding of PM-associated cognitive vulnerabilities.

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