Clinical Manifestations.

Background: Dementia with Lewy bodies (DLB) and Alzheimer's disease (AD) differ in their cognitive characteristics. Subscales of the Rowland Universal Dementia Assessment Scale (RUDAS) provide an opportunity to test these cognitive domains across the two conditions. Multiple brief cognitive screening tools have been evaluated to differentiate specific types of dementia, but there are no reports regarding RUDAS yet.

Methods: One hundred and twenty-one [DLB (n = 46) and AD (n = 75)] patients enrolled in the Instituto Peruano de Neurociencias (IPN). AD cases were derived from the GAPP study (NIA grant #alz090494AG069118). Independent group t-tests and chi-square tests were used to examine differences in key demographic variables and in RUDAS sub-scores (Orientation, praxis, construction, judgment, memory, and language) between groups.

Results: On average, AD patients were older and had a lower total RUDAS score. AD and DLB patients performed significantly differently (p < 0.05) on all RUDAS cognitive domains (table 1). The RUDAS memory sub-score was particularly effective in fully differentiating patients with AD from ones with DLB (AD: mean = 1.7, range = 0-2; DLB: mean = 5, range = 4-8; Figure 1).

Conclusion: Our results provide preliminary evidence of the utility of RUDAS to differentiate between cases diagnosed with AD and DLB in urban Peruvian populations. Future work will focus on confirming if the RUDAS memory sub-score can aid in differentiating DLB from AD in larger, community-dwelling populations in Peru.