Date of Award


Document Type


Degree Name

Doctor of Philosophy (PhD)



First Advisor

W. Drew Gouvier


Much debate exists as to the independence of subcortical dementia as a recognizable clinical entity. Researchers in the dementia area seem to accept that cortical dementias are relatively more incapacitating than subcortical dementias. However, there are no empirical studies to support this claim. Impairment in adaptive functioning is one criterion to be met in the diagnosis of dementia according to DSM-III-R (APA, 1987) and NINCDS-ADRDA criteria (McKhann, Drachman, Folstein et al., 1984). However, a comparison of the degree of impairment in adaptive functioning between subcortical and cortical diagnostic groups of dementia has never been systematically and empirically investigated. This study examined the degree to which adaptive functioning can be used to differentiate groups of prototypical subcortical and cortical pathology groups, as well as normal age control subjects. Results of Discriminant Function Analysis covarying effects due to gender differences yielded a significant discriminant function, suggesting that adaptive functioning separates the groups. The PD subjects were correctly classified by DFA at a much lesser rate than either AD or NORM subjects. Thus, despite marked differences in neuropsychological functioning, the PD subjects overlap considerably with the other subject groups with regard to adaptive functioning. Follow-up regression analysis suggests that the discriminating variance attributable to adaptive functioning is shared by cognitive status. Indeed, the adaptive variables contributing most to group separation all shared an element of cognition. It is suggested that separating cognitive status from adaptive functioning is perhaps not as important as measuring both facets of behavior in concert. Measuring both areas will allow the clinician to gain a complete understanding of the individual patient.