Title

The Endogenously Evoked P50 Potential in Patients with Alzheimer's Disease and Their First-Generation Biological Children

Date of Award

2004

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Psychology

First Advisor

Gary E. Jones

Advisor Department

Psychology

Abstract

Objective . This study examined whether the endogenously evoked P50 component could correctly identify individuals with Alzheimer's disease (AD), and if successful, its relevance to asymptomatic children of AD patients. The P50 component is a sensory gating potential modulated by the neurotransmitter, acetylcholine, and is involved with gating during sleep. Medical research has revealed that patients with AD exhibit a reduction in acetylcholine. Methods . P50 was recorded at Fz, Cz, & Pz in four groups (AD, AD-Control (AD-C), Children of AD (CAD), & Children of AD-Control (CAD-C)). Twenty subjects in each group had P50 elicited using the standard paired-click paradigm. P50 ratios were calculated (Click 2/Click 1). Results . Alzheimer's patients demonstrated less P50 suppression (Fz, p = .122, Cz, p = .065, Pz, p = .008) than their controls. There were no significant differences between the CAD and CAD-C groups. An evaluation of the response to both clicks was completed with all groups included. The results reveal significant differences in response to the second click, with the AD group demonstrating significantly increased P50 amplitudes than all other groups. Conclusions . These findings suggest that AD patients show significantly less P50 suppression than their controls, possibly resulting from cholinergic dysfunction. The P50 component in asymptomatic children of AD patients is not similarly affected at this time in the disease process.