A meta-analysis of the accuracy of the Addenbrooke's Cognitive Examination ( ACE) and the Addenbrooke's Cognitive Examination-Revised (ACE-R) in the detection of dementia

Background: The Addenbrooke's Cognitive Examination (ACE) and its Revised version (ACE-R) are relatively new screening tools for cognitive impairment that may improve upon the well-known Mini-Mental State Examination (MMSE) and other brief batteries. We systematically reviewed diagnostic accuracy studies of ACE and ACE-R. Methods: Published studies comparing ACE, ACE-R and MMSE were comprehensively sought and critically appraised. A meta-analysis of suitable studies was conducted. Results: Of 61 possible publications identified, meta-analysis of qualifying studies encompassed 5 for ACE (1,090 participants) and 5 for ACE-R (1156 participants); of these, 9 made direct comparisons with the MMSE. Sensitivity and specificity of the ACE were 96.9% (95% CI = 92.7% to 99.4%) and 77.4% (95% CI = 58.3% to 91.8%); and for the ACE-R were 95.7% (95% CI = 92.2% to 98.2%) and 87.5% (95% CI = 63.8% to 99.4%). In a modest prevalence setting, such as primary care or general hospital settings where the prevalence of dementia may be approximately 25%, overall accuracy of the ACE (0.823) was inferior to ACE-R (0.895) and MMSE (0.882). In high prevalence settings such as memory clinics where the prevalence of dementia may be 50% or higher, overall accuracy again favored ACE-R (0.916) over ACE (0.872) and MMSE (0.895). Conclusions: The ACE-R has somewhat superior diagnostic accuracy to the MMSE while the ACE appears to have inferior accuracy. The ACE-R is recommended in both modest and high prevalence settings. Accuracy of newer versions of the ACE remain to be determined.