Cortisol and Working Memory In Boys With Fragile X Syndrome

Shinkareva for their feedback and support throughout this process. iv ABSTRACT Fragile X Syndrome (FXS) is a neurodevelopmental disorder and the most common cause of inherited intellectual disability. Although FXS is associated with global cognitive impairments, specific deficits in working memory have been reported in young males with FXS. Working memory is an important cognitive process that involves the ability to temporarily store and manipulate information over a short period of time. Deficits in working memory can negatively impact an individual's academic, behavioral, and social functioning. Chronic stress can adversely influence working memory performance and can be measured physiologically through salivary cortisol. It is important to study the complex relationship of how physiological and cognitive processes interact and develop over time to aid in the specificity of assessments and treatments for individuals that are vulnerable to develop cognitive impairments over time. The present study investigates the relationship of developmental trajectories of working memory performance in boys with FXS compared to typically developing boys. This study also examined the relationship of salivary cortisol on memory performance over time in boys with FXS and typically developing boys. Results from multilevel models indicate specific cognitive deficits in working memory performance in boys with FXS compared to typically developing boys. No significant differences were seen in working memory trajectories between boys with FXS and typically developing boys after controlling for mental age. Results further indicated that boys with FXS had higher levels of baseline cortisol that negatively impacted working memory performance over time compared to v typically developing boys. This study highlights the need for further investigation on how dynamic physiological and cognitive factors interact and influence an individual's cognitive development over time.