Toward a new standard for the Addenbrooke’s Cognitive Examination-III (ACE-III) adaptation – Lithuanian normative data for community-dwelling adults

INTRODUCTION: The Addenbrooke's Cognitive Examination-III (ACE-III) is a widely used dementia screening instrument, translated into more than 40 languages. However, its cutoff values vary considerably across adaptations-ranging from 62 to 89 for dementia and 71 to 89 for mild cognitive impairment (MCI). This variability reflects the limitation of the single-threshold approach, which overlooks demographic influences and highlights the need for individualized norms. OBJECTIVE: The study aimed to adapt and validate the Lithuanian version of the ACE-III (ACE-III-LT) and establish population-based normative data stratified by age and education. METHODS: A total of 308 community-dwelling adults aged 45 years and older and 105 patients clinically diagnosed with dementia or MCI were assessed using the ACE-III-LT and the MMSE-2. RESULTS: Percentile norms were developed for five age groups and three education levels (≤12, 13-16, ≥17 years). The ACE-III-LT scores were significantly associated with both age and education, with stronger effects in older participants. Receiver operating characteristics (ROC) analyses indicated optimal cutoffs of 76 points for dementia (sensitivity = 96%, specificity = 96%) and 86 points for MCI (sensitivity = 88%, specificity = 81%). CONCLUSIONS: This study provides one of the largest ACE-III normative datasets to date, allowing for age- and education-adjusted interpretation. We recommend that future adaptation studies adopt this stratified method of norm development to enhance the diagnostic precision, clinical validity, and fairness of cognitive assessments.