Validity of the two different scoring methods of the Clinical Dementia Rating scale in staging and detection of cognitive impairment in the Peruvian population

INTRODUCTION: In Peru, the Global Deterioration Scale is the only available tool for assessing dementia severity. The Spanish translation and cultural adaptation of the Clinical Dementia Rating (CDR) is used locally but requires formal psychometric validation in the Peruvian sociocultural context. METHODS: A total of 1,600 older adults: 902 controls, 271 mild cognitive impairment (MCI), and 427 Alzheimer's disease patients (AD) were assessed to validate two CDR scoring methods: CDR Global Score (CDR-GS) and CDR Sum of Boxes Score (CDR-SB). Discriminative validity, inter-item reliability, and concurrent validity were evaluated using MMSE, RUDAS, PFAQ, and Uniform Data Set (UDS) v3 Neuropsychological Battery. RESULTS: CDR demonstrated high reliability and validity among normal cognition, mild cognitive impairment, and AD. For AD screening, CDR-SB showed 98.2% sensitivity and 99.6% specificity, while CDR-GS demonstrated 99.8% sensitivity and 100% specificity. DISCUSSION: The Peruvian CDR version exhibited good psychometric properties comparable to those reported in Latin American CDR validation studies.