Differential diagnosis of Alzheimer dementia and depression using the Dean-Woodcock Neuropsychological Assessment System

This study investigated the utility of the cognitive measures of the Dean-Woodcock Neuropsychological Assessment System (D-WNAS) in the differential diagnosis of Alzheimer dementia (AD) from depression. Past research has found an overlap of symptoms in the early stages of AD and those found in geriatric depression. In both instances, patients are likely to report memory loss, attention deficits, and mood disturbances. As a result of this similarity, differentially diagnosing one from another is a vexing problem for the clinical practitioner. Although a number of screening measures have been offered, none have proven to be clinically useful. Some have proposed this is the result of reliance upon use of single-factor measures. Indeed, many have proposed a multiple factor assessment model would be of more utility in diagnosing AD and depression. Considering the importance of an accurate diagnosis in treatment, this study utilized a multiple factor cognitive model offered by the Dean-Woodcock Neuropsychological Assessment System to differentiate AD from depression.Specifically, subtest scores of the Woodcock-Johnson III - Tests of Cognitive Ability (WJ-III; cognitive measure of the Dean-Woodcock Neuropsychological Assessment System) were compared. Participants (n = 172) fell into one of three groups (i.e. Depressed, Demented, or Normal) based on the diagnoses of a board certified neurologist and neuropsychologist. Results showed clinical groups performed more poorly than normal participants on tests of the WJ-III. In addition, AD participants differed significantly from depressed participants on the Visual Matching and Spatial Relations tests of the WJ-III. However, in all, the WJ-III demonstrated a classification hit rate of less than 70%. Although groups were found to differ in specific ways, the classification hit rate of the WJ-III suggested it could not differentially diagnose AD from depression alone.Department of Educational PsychologyThesis (Ph. D.