THE ADDENBROOKE’S COGNITIVE EXAMINATION-REVISED (ACE-R) IN THE DIAGNOSIS OF MILD COGNITIVE IMPAIRMENT DUE TO ALZHEIMER’S DISEASE: A PRELIMINARY ANALYSIS

Abstract

The ACE-R allows a brief evaluation of five cognitive domains and has proven to be useful in detecting dementia. However, its diagnostic value in mild cognitive impairment (MCI), especially due to Alzheimer's disease (AD), has been much less investigated. The battery also offers the VLOM ratio sub-score that comprises the ratio of the scores of verbal fluency + language / orientation +memory. The test was administered to 19 MCI patients who converted to AD dementia over a three-year follow-up, to 90 probable mild AD dementia and to 98 cognitively healthy subjects, matched for age and education. All subjects were also submitted to the Mattis Dementia Rating Scale. The three groups were compared and cut-off points for ACE-R total score and VLOM ratio were defined by ROC curve analysis. Areas under ROC curves-AUC (cut-off points - % sensitivity / % specificity) for ACE-R were: MCI-AD x controls = 0.755 (<87 - 100.0/45.9), AD dementia x controls = 0.864 (<80 - 77.7/79.6), MCI-AD x AD dementia = 0.738 (<76 - 60.0/84.2). VLOM ratio analysis displayed an AUC = 0.883 (>2.9 - 84.2/81.6) for MCI-AD x controls. The preliminary results confirm good sensitivity of the ACE-R in discriminating MCI-AD from healthy controls, particularly through the VLOM ratio. However, the specificity must be improved. The test also demonstrated good capacity on differentiating mild AD dementia from controls. MCI-AD patients displayed a mean score eight points higher than AD dementia subjects, an information that may be useful in the clinical setting. The inclusion of additional MCI patients will allow to investigate the value of the ACE-R in predicting MCI conversion to dementia, as well as to explore alternative component analysis as a strategy to achieve a better differential diagnosis between MCI-AD from MCI non-converters or from MCI converting into non-AD dementias.