Date of Award


Degree Type


Degree Name

Doctor of Psychology (PsyD)

Committee Chair

BJ Scott, Psy.D

Second Advisor

Jane M. Tram, Ph.D.

Third Advisor

Christiane Brems, Ph.D. ABPP


The purpose of this study is to explore validity of the Clinical Dementia Rating Scale (CDR) in measuring dementia among individuals with Parkinson’s disease. The CDR was created for use in patients with Alzheimer’s disease and, to date, there are no published studies specifically examining if the CDR is appropriate for patients with PD. The data were obtained from the National Alzheimer’s Coordinating Center database (The NACC database is funded by National Institute on Aging grant number U01 AG016976). There were 490 subjects (mean/SD: Age = 72.11/9.20; education = 16.09/6.07; 73.3% male) diagnosed with dementia (n= 151), mild cognitive impairment (n= 186), or normal cognition (n = 153) by a physician. Inclusion criteria were a diagnosis of Parkinson’s disease. Exclusion criteria were possible or probable Alzheimer’s disease or other confounding conditions. Sensitivity, specificity, positive predictive value and negative predictive value were calculated for the previously published CDR Global Score as well as the Sum of Boxes cutoff scores for each of the 3 diagnostic categories. Finally, new cutoff scores were calculated using sensitivity and specificity values derived from the Receiver Operating Characteristic curves. The results indicate the CDR is a useful tool in identifying dementia in patients with Parkinson’s disease when the cutoff scores are adjusted.


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