Validation of the Portuguese version of Addenbrooke's Cognitive Examination III in mild cognitive impairment and dementia

Background. Cognitive assessment is central to the diagnosis of cognitive impairment and dementia, and it should be performed in all patients in the early stages of the disease. Recently, the 3'' version of Addenbrooke's Cognitive Examination (ACE-III) has been developed in order to improve the previous versions. Objectives. The aim of this study was to determine the psychometric properties of the Portuguese version of ACE-Ill, namely: reliability and discriminative validity (sensitivity and specificity) in the identification of mild cognitive impairment (MCI) and dementia, in comparison to other neuropsychological screening tests, as well as to establish its concurrent and divergent validity. Material and methods. The study encompassed a sample of 90 participants distributed into 3 groups: Control (n = 30), MCI (n = 30) and Dementia (n = 30). In addition to ACE-III, Clinical Dementia Rating (CDR) and Montreal Cognitive Assessment (MoCA) were also used. Results. The reliability of ACE-III was very good (a =0.914). ACE-III significantly differentiated the 3 groups. The receiver operating characteristic (ROC) curves significantly favored ACE-III in comparison to another screening test - MoCA. ACE-III presented higher levels of sensitivity and specificity. Its total score correlated positively with the results on MoCA (p = 0.912; p < 0.001) and negatively with a depression scale (p = -0.505; p < 0.001). Conclusions. The Portuguese version of ACE-III has very good reliability and high diagnostic capacity in the context of MCI and dementia. ACE-III also holds concurrent and divergent validity.