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S074-4

Microstructural Integrity of White Matter Tracts Is Associated with
Intra-Individual Variability in Children with ADHD

Hsiang-Yuan Lin1, Shoou Lian Hwang2, Susan Shur-Fen Gau3, Wen-Yih Isaac Tseng4

1Department of Psychiatry, National Taiwan University Hospital and College of Medicine, Taiwan 2Department of
Occupational Therapy, Graduate of behavioral science, Division of Clinical Psychology, Chang Gung University,
Taiwan 3Department of Psychiatry, National Taiwan University Hospital and College of Medicine, Taiwan 4Center
of Optoelectronic Medicine Center, College of Medicine, National Taiwan University, Taiwan

Background/Objective: Despite that intra-individual variability in reaction time (IIV-RT) is a
common neuropsychological impairment in individuals with attention-deficit/hyperactivity disorder
(ADHD), neural substrates underpinning the deficits remain elusive. Previously, we found that
IIV-RT is associated with the integrity of mid-cingulum tract in ADHD, and relate with frontostriatal
integrity in typically developing controls (TDC). Herein, we aim to comprehensively investigate
relationships between the white matter (WM) tracts germane to major cognitive theories of
behavioral inconsistency and IIV-RT in ADHD.

Method: The 221 participants (aged 8-18 years) consist of 117 children with ADHD, 104 TDC
children received Diffusion Spectrum Imaging scans and the Conners’ Continuous Performance Test.
Ex-Gaussian parameters, mu, sigma, and tau, were derived to represent IIV-RT. Explorative factor
analysis of 42 WM tracts relevant to cognitive theories was perform to identify latent components.
Stepwise regression procedures were used to select the optimal models to predict RT-IIV from WM
integrity, as indexed by regression factor scores, respectively for ADHD and TDC.

Result: Larger tau and sigma values, and greater omission errors were found in children with ADHD.
We identified 6 latent components from all WM tracts investigated. Among them, regression factor
scores from the component, including microstructural integrity of mid-cingulum, fronto-striatal tracts,
superior longitudinal fasciculus, and forceps minor, were associated with tau values and omission
errors of ADHD, while sigma values of TDC.

Conclusion: This study highlights the disorder-specific alteration of white matter tracts in adults
with ASD. Future studies in patients with other age range and both genders using DSI and other
imaging modalities are needed to elucidate disorder-specific brain structural biomarkers for these
two disorders.