Masters Theses

Date of Award

5-2002

Degree Type

Thesis

Degree Name

Master of Arts

Major

Psychology

Major Professor

Joel Lubar

Committee Members

D. Baldwin, J. Malone

Abstract

This pilot study utilized (Low Resolution Electromagnetic Tomographic Analysis (LORETA), a brain-imaging alternative to classical QEEG, to evaluate early stage Alzheimer (AD) participants (n = 6) and healthy similar-aged (Controls) participants (n = 8) during the Counting Stroop. The Counting Stroop is a validated analog to the ColorWord Stroop that provides an attentional challenge and is demonstrated to activate cortical structures in the motor speech areas and the anterior cingulate. Two tasks were recorded and subsequently subtracted: the neutral stimulus (NS) in which animal words were presented multiple times on a single slide and the incongruent stimulus (IS) in which a number word was presented multiple times on a single slide. The NS was subtracted from the IS to create difference maps. None of the within group T-tests that make up the group difference maps revealed statistically significant differences. However, several qualitative differences are evident between the two groups. The patterns of activation that differ between the AD and Control groups and description of trends that support cited literature references are worth reporting. Results include group relative power differences that clearly distinguish the two groups. Supporting the literature of relative power differences in eyes-closed baselines, the AD group produced greater relative power in the Delta, Theta and Alpha frequency bands while the Control group produced greater relative power in the Beta I and Beta 2 bands. Other qualitative differences include differential activation at the insula. MRI data suggests that early damage occurs at the parahippocampal gyrus and the entorhinal cortex. The most rostral aspects of these neural locations abut the insula. Finally, the differences in group activation in the temporal lobes supports a possible early diagnostic to apply to those who will eventually develop clinical Alzheimer's disease.

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