Adult ADHD and cognitive dispersion: characterizing variability in performance across cognitive tasks in older adults with and without ADHD

Klepacz, Laura Marie (2023) Adult ADHD and cognitive dispersion: characterizing variability in performance across cognitive tasks in older adults with and without ADHD. Masters thesis, Northern Arizona University.

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Abstract

Most research on cognitive performance among individuals with Attention Deficit/Hyperactivity Disorder (ADHD) focuses on younger persons and on cognitive variability within speeded response-time tasks. Dispersion (i.e., variability across a range of cognitive domains) is emerging as a promising indicator of age-related and pathological cognitive impairment. There has not yet been an evaluation of differences in dispersion among older adults with and without ADHD to determine if dispersion may be a behavioral marker of ADHD. We address this gap by assessing associations of age, ADHD status, and ADHD severity with dispersion. We hypothesized that older adults would exhibit greater dispersion than comparatively younger adults and explore whether individuals with ADHD and individuals with more ADHD symptoms exhibit greater dispersion than individuals without ADHD and with fewer symptoms. In a sample of 231 adults from the Longitudinal Aging Study Amsterdam (Average age=71.64 years, SD=7.7, Range = 59% female), 23 individuals met DSM-IV criteria for ADHD and 208 were classified as neurotypical. Participants completed 13 tasks spanning domains of attention, fluency, memory, processing speed, and reasoning. Dispersion across the tasks was calculated as an intraindividual standard deviation for each participant. We regressed dispersion on age, ADHD status, and ADHD symptoms and adjusted for sex, education, and depressive symptoms. Older age was significantly associated with greater dispersion (Est =0.06, SE=0.03, p=0.02). However, dispersion profiles did not vary as a function of ADHD status (Est.=-0.90, SE=0.71, p>.05), or number of ADHD symptoms (Est.=-0.03, SE=0.03, p>.05). Results suggest that dispersion across cognitive tasks may not be a sensitive marker of ADHD in older adults, although statistical power to detect differences was low in the current study. Age was a significant correlate of higher dispersion. Additional research is required to gain more understanding of ADHD in older adulthood. Though our study suggests that within-person fluctuations measured by variability observed across cognitive domains may not be a behavioral marker of ADHD, other indices of variability, such as response time inconsistency, may be relevant for future work on behavioral descriptions of ADHD across the lifespan.

Item Type:	Thesis (Masters)
Publisher’s Statement:	© Copyright is held by the author. Digital access to this material is made possible by the Cline Library, Northern Arizona University. Further transmission, reproduction or presentation of protected items is prohibited except with permission of the author.
Keywords:	ADHD; Cognition; Dispersion; Older adulthood
Subjects:	B Philosophy. Psychology. Religion > BF Psychology
NAU Depositing Author Academic Status:	Student
Department/Unit:	Graduate College > Theses and Dissertations College of Social and Behavioral Science > Psychological Sciences
Date Deposited:	15 May 2025 21:58
Last Modified:	15 May 2025 21:58
URI:	https://openknowledge.nau.edu/id/eprint/6142

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