The psychometric properties of the third version of Addenbrooke's Cognitive Examination (ACE-III) in a sample of Iranian older adults

Introduction: Cognitive problems such as dementia are common in older adults and their prevalence increases with age. The early identification and diagnosis of patients with dementia can help with their treatment and improve their quality of life. The present study was conducted to investigate the psychometric properties and validate the Addenbrooke's Cognitive Examination (ACE) in a sample comprising older adult Iranians.

Methods: The present cross-sectional and correlational study recruited 300 older adults in Kahrizak Geriatric Nursing Home in Iran, including 198 men and 102 women selected using simple random sampling. The data collection tools comprised the ACE-III, the Mini–Mental State Examination (MMSE) and the Geriatric Depression Scale (GDS). Confirmatory factor analysis was used to investigate the construct validity of the test, and the Pearson’s correlation coefficient to examine its convergent and divergent validity. Cronbach’s alpha was also used to investigate the internal consistency of the items. To examine the diagnostic validity, cut-off point, sensitivity and specificity of the test were calculated.

Results: The results found correlations between the ACE-III and other tools (P>0.01), thus suggesting a proper convergent and divergent validity. The test-retest reliability coefficient with a two-week interval and the Cronbach’s alpha of the ACE-III were respectively calculated as 0.90 and 0.95. The optimal cut-off point that struck a balance between sensitivity and specificity was found to be 75, with a sensitivity of 0.99 and specificity of 0.95. The results of the factor analysis indicated a good fit of the single-factor structure of this test.

Conclusion: The ACE-III has good psychometric properties and it can be used to screen for dementia.