Psychometric properties and diagnostic usefulness of the Addenbrooke's Cognitive Examination-revised in a Chilean elderly sample

Abstract

Background - The Addenbrooke’s Cognitive Examination - Revised (ACE-R) is a good alternative to the Mini Mental State Examination (MMSE) for assessing cognitive capacities in dementia. Aim - To estimate the psychometric properties and diagnostic utility of the Addenbrooke’s Cognitive Examination-Revised (ACE-R) in a Chilean elderly sample. Material and Methods - ACE-R was adapted for the Chilean population (ACE-R-Ch) and then administered to 60 dementia patients, 22 mild cognitive impairment (MCI) patients and 45 control subjects in addition to the MMSE for assessing global cognitive efficiency. Caregivers of dementia patients and collateral sources of MCI patients and elderly subjects without dementia were interviewed with measures of dementia severity, functional status in activities of daily living and cognitive changes. Convergent validity, internal consistency reliability, cutoff points, sensitivity and specificity for ACE-R-Ch were estimated. Results - Regarding convergent validity, the ACE-R-Ch showed significant correlations (p < 0,001) with another cognitive measure (r = 0,952 with MMSE), a rating for dementia severity (Spearman rho=-0,822 with CDR), functional capacity assessments (r = -0,70 with ADLQ-Ch; r = -0,725 with PFAQ-Ch; and r = 0,650 with IADL Scale) and a measure of cognitive changes (r = -0,633 with AD8-Ch). In terms of reliability, the test had a Cronbach alpha coefficient of 0.918. The best cut-off point to distinguish cases of dementia from control subjects was a score of 76, which reached a sensitivity of 0.92 and a specificity of 0.93. Conclusions - The ACE-R-Ch showed acceptable psychometric properties, becoming a valid and reliable instrument to assess global cognitive efficiency or cognitive impairment. Its diagnostic utility to detect dementia patients also worked very well in a Chilean elderly sample.