Dissertations, Theses, and Capstone Projects

Date of Degree

2007

Document Type

Dissertation

Degree Name

Ph.D.

Program

Psychology

Advisor

Jeffrey M. Halperin

Committee Members

Ray Johnson, Jr.

Tina Moreau

Kurt P. Schulz

B.J. Casey

Subject Categories

Psychology

Abstract

The objective of this dissertation was to examine whether post-error reaction time slowing, an index of self-regulation, is impaired in individuals with Attention-Deficit/Hyperactivity Disorder (ADHD) at two separate developmental time points: preschool and adolescence. Two studies were conducted with separate cohorts. Study 1 examined post-error slowing in a sample of preschool children rated by parents, teachers, and clinicians as exhibiting high levels of ADHD symptoms. In addition to group comparisons based on symptom status, a cross-sectional examination of age-related changes in post-error slowing in typically developing preschoolers (controls) was also conducted. Study 2 compared post-error slowing in individuals diagnosed with ADHD in childhood, who were diagnostically reassessed in adolescence for persistence versus remission of the disorder, relative to a well-matched comparison group. Post-error slowing was examined as a function of both childhood and adolescent diagnostic status. The results of Study 1 indicated that, although children as young as 3 years of age exhibited post-error slowing on a computerized reaction time task, the expected increases in post-error slowing with age were not found. Further, hyperactive/inattentive preschool children exhibited reduced levels of post-error slowing relative to controls. Thus, symptomatic preschool children appeared to be impaired on this index of self-regulation. Post hoc exploratory analyses suggested some support for greater attentional difficulties in hyperactive/inattentive children who failed to exhibit post-error slowing. Study 2 did not yield any significant results. Contrary to expectations, individuals with ADHD did not exhibit reduced levels of post-error slowing whether examined as a function of either childhood (ADHD, Control) or adolescent diagnostic status (Persisters, Remitters, Controls). Findings from Study 1 are discussed in the context of developmental changes in the complex neural circuitry underlying both post-error slowing and ADHD. Further investigation of the contributions of component cognitive processes (i.e., error detection, affect/motivation, attention, self-regulation) and their neural bases is recommended. In addition, consideration of post-error slowing as a potential endophenotype may be of benefit to research regarding the genetic underpinnings of ADHD.

Comments

Digital reproduction from the UMI microform.

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