Date of Award


Degree Type


Degree Name

Doctor of Philosophy in Psychology


Clinical Psychology



First Advisor

David Faust


This study evaluated the viability of a potential strategy for improving the detection of cognitive decline over currently available IQ-based methods. The proposed strategy makes use of differential cognitive effects across different neurocognitive disorders. It involves examining estimated/obtained difference scores (D-scores) for the specific cognitive domain(s) (SCDs) most affected by a disorder. The current study undertook a broad feasibility test of the strategy as a preliminary step in the development of specific cognitive domain estimation methods (SCDEMs). Clinical and control group score distributions were reconstructed from IQ and SCD test (SCDT) means and standard deviations reported in previously published studies of mild Alzheimer 's disease (mild AD), chronic alcohol abuse (CAA), and mild traumatic brain injury (mTBI). For each test, the percentage of area shared by the two reconstruct ed clinical and control distribution curves was calculated. Percent overlap values for tests measuring the same SCD were then pooled across studies of the same disorder and averaged, thereby forming indexes that served to estimate SCD sensitivity. Comparable IQ indexes were also formed. The average SCD and IQ overlap values were then compared. The main result suggests that diagnostic accuracy could be improved considerably for mild AD, and, to a lesser extent, for CAA and mTBI, by using SCD versus IQ D-scores. The development of SCDEMs appears clinically worthwhile, especially given their potential application to a disorder of such importance as AD, although their utility may be lower or considerably lower, for other disorders.



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