Advisor(s)

Donna Murdaugh

Committee Member(s)

Jarred Younger
Olivio Clay

Document Type

Thesis

Date of Award

6-18-2026

Degree Name

Master of Science (MS)

School

College of Arts and Sciences

Department

Psychology

Abstract

Pediatric acute lymphoblastic leukemia (ALL) survivors face treatment-related risk for late-emerging cognitive difficulties. Chemotherapy can disrupt white-matter structure leading survivors to experience subtle but persistent challenges with processing speed, working memory, and executive functioning. However, cognitive outcomes vary widely even among survivors with similar treatment exposures. To better understand this variability, this study examines how the brain adapts after treatment and how that adaptation is shaped by the environment. This study used diffusion magnetic resonance imaging (MRI) connectomics to characterize white matter network organization in 18 pediatric ALL survivors compared with 20 typically developing controls (ages 10-18). Structural connectomes were mapped using advanced diffusion MRI methods that model white matter pathways. Structural connectivity was quantified with graph-theory metrics, which represent the brain as nodes (regions) and edges (connections). Graph-theoretical metrics of global efficiency, modularity, and participation coefficient (PC) were used to quantify network integration and segregation. Global efficiency and modularity, measuring whole-brain communication efficiency and network segregation, respectively, did not differ between groups (ps > .95). Survivors showed higher PC (cross-network integration) at both whole-brain and regional levels. PC was higher within the visual, control (frontoparietal), and dorsal-attention networks, and most notably in right prefrontal and bilateral occipital regions (g = 0.45–0.83, pₚₑᵣₘ = .02–.14). Among survivors, greater PC in control and visual networks was positively related to cognitive flexibility, working memory, and processing speed (partial ρ = .41–.63, ps = .01–.20). Younger age at diagnosis was associated with slower processing speed and lower control network PC, and the presence of academic supports was linked to higher modularity and lower working memory, likely reflecting greater cognitive need. Findings suggest that survivors may recruit visual and control networks as compensatory “connector hubs” to support communication across the brain following treatment-related disruption. This pattern aligns with models of neural adaptation after neurological insult, where damage leads to increased connectivity in network hubs (Hillary & Grafman, 2017). Together, these findings help explain how pediatric ALL survivors’ brains may adapt to maintain cognitive function after cancer treatment.

Keywords

Diffusion MRI;Graph Theory;Neuropsychology;Pediatric Acute Lymphoblastic Leukemia;Pediatric Cancer Survivorship;Structural Connectomics

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