Psychology ETDs

Publication Date

1-31-2013

Abstract

Attention Deficit Hyperactivity Disorder (ADHD) has gained acceptance as a neurobiological disorder, supported by a growing body of literature that documents differences in brain structure and function in individuals diagnosed with ADHD. There is growing interest in exploring patterns of neurometabolite concentrations through the methods of proton spectroscopy (1H-MRS). Previous studies have employed single voxel techniques, examining neurometabolite concentrations in small, localized regions of brain tissue. This study is the first to employ Spectroscopic Imaging (SI), which allows for acquisition of neurometabolite spectra from a larger sample of brain tissue, in the cerebral cortex of individuals diagnosed with ADHD. Nine adolescents and young adults diagnosed ADHD and twelve control participants were enrolled in the study. Similar to previous findings, the ADHD group demonstrated significant reductions in gray matter volumes of brain regions relevant for sustained attention, inhibition, and working memory. Additionally, performance on measures of visual-spatial problem solving, academic achievement, and cognitive flexibility/response inhibition was more impaired than controls. Preliminary analyses of the SI neurometabolite data revealed few significant results, but several trends were noted, including some sex-related differences in neurometabolite concentrations. As anticipated, different patterns of correlations between neurometabolite concentrations and performance on measures of attention were discovered for the ADHD group in comparison to controls. The present study also sought to extend the literature on ADHD by providing a preliminary exploration of neurometabolite concentrations in late adolescence in the context of functional impairment in young adulthood. Although many individuals report symptom remediation when they enter adulthood, functional outcomes indicate that the impact of the disorder is far reaching, impacting aspects of quality of life, academic achievement, employment, relationships, and engagement in risk behaviors. Difficulties in collection of follow-up data limited the findings regarding functional outcome and neurological correlates. Implications and ideas for future research involving 1H-MRS techniques and ADHD are discussed. Overall, the study highlights trends and patterns indicative of a unique neurometabolic profile of individuals with ADHD, suggesting that additional longitudinal research is necessary to advance our understanding of this developmental disorder.

Degree Name

Psychology

Level of Degree

Doctoral

Department Name

Psychology

First Committee Member (Chair)

Yeo, Ronald

Second Committee Member

Campbell, Richard

Third Committee Member

Hill, Dina

Fourth Committee Member

Thoma, Robert

Language

English

Keywords

Attention-deficit hyperactivity disorder--Physiological aspects. Brain--Spectroscopic imaging, Brain--Spectroscopic imaging, Nuclear magnetic resonance spectroscopy--Diagnostic use.

Document Type

Dissertation

Download

Share

COinS