Publication Date

2011-06-29

Availability

Embargoed

Embargo Period

2012-06-28

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PHD)

Department

Psychology (Arts and Sciences)

Date of Defense

2010-11-23

First Committee Member

Phillip M. McCabe

Second Committee Member

Bonnie E. Levin

Third Committee Member

Heather L. Katzen

Fourth Committee Member

Maria M. Llabre

Fifth Committee Member

Neil Schneiderman

Abstract

Apathy is a debilitating non-motor symptom in Parkinson’s disease (PD) that is closely associated with cognitive dysfunction, depression, and caregiver burden. The proposed etiology and operational definition of apathy involves a tripartite model that includes cognitive, behavioral, and emotional manifestations. This theoretical model has not been statistically validated. We examined the tripartite structure of apathy in PD, and subsequent associations between apathy factors and demographic, disease, and neuropsychological measures. One hundred forty-one patients with idiopathic PD underwent neurological examination and comprehensive neuropsychological testing including the Apathy Evaluation Scale (AES). Statistical analyses included correlation, means comparison, item analysis, and confirmatory factor analysis using SEM. The AES was found to be a valid and reliable measure of apathy. Although a tripartite model of apathy was not supported, a novel 3-factor structure of apathy (R-Apathy) emerged characterized by Cognitive/Emotional and Behavioral factors. Both education and depression were significantly associated with R-Apathy. When these were controlled, R-Apathy was associated with impairment in select executive function and visuospatial skills. Apathy remains an important dimension in understanding nonmotor changes in PD. As a whole, apathy correlated with specific areas of neuropsychological dysfunction apart from the influence of depression. Manifestations of apathy such as mental disengagement and behavioral withdrawal are key features of the disease presentation. The importance of evaluating apathy as a contributing factor to patients’ neurocognitive status, mood, and psychosocial functioning should not be underestimated. Furthermore, an apathy evaluation should be included as a standard part of a Parkinson’s evaluation.

Keywords

Apathy; Parkinson's Disease; Apathy Evaluation Scale; cognitive function; neuropsychology; apathy and depression

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