Objective: To compare the accuracy of the Rowland Universal Dementia Assessment Scale (RUDAS) and the Folstein Mini-mental State Examination (MMSE) for diagnosis of dementia in a multicultural cohort of elderly persons.
Methods: A total of 129 community-dwelling persons were selected at random from a database of referrals to an aged-care team. Subjects were stratified according to language background and cognitive diagnosis, and matched for age and gender. The RUDAS and the MMSE were administered to each subject in random order. Within several days, a geriatrician assessed each subject for dementia (DSM-IV criteria) and disease severity (Clinical Dementia Rating Scale). All assessments were carried out independent and blind. The geriatrician also administered the Modified Barthel Index and the Lawton Instrumental Activities of Daily Living Scale, and screened all participants for non-cognitive disorders that might affect instrument scores.
Results: The area under the receiver operating characteristic curve (AUC) for the RUDAS [0.92, 95% confidence interval (95%CI) 0.85-0.96] was similar to the AUC for the MMSE (0.91, 95%CI 0.84-0.95). At the published cut-points (RUDAS < 23/30, MMSE < 25/30), the positive and negative likelihood ratios for the RUDAS were 19.4 and 0.2, and for the MMSE 2.1 and 0.14, respectively. The MMSE, but not the RUDAS, scores were influenced by preferred language (p = 0.015), total years of education (p = 0.016) and gender (p = 0.044).
Conclusions: The RUDAS is at least as accurate as the MMSE, and does not appear to be influenced by language, education or gender. The high positive likelihood ratio for the RUDAS makes it particularly useful for ruling-in disease.