A brief cognitive test battery to differentiate Alzheimer's disease and frontotemporal dementia

Objectives: To validate a simple bedside test battery designed to detect mi ld dementia and differentiate AD from frontotemporal dementia (FTD). Method s: Addenbrooke's Cognitive Examination (ACE) is a 100-point test battery th at assesses six cognitive domains. Of 210 new patients attending a memory c linic, 139 fulfilled inclusion criteria and comprised dementia (n = 115) an d nondementia (n = 24) groups. The composite and the component scores on th e ACE for the two groups were compared with those of 127 age- and education -matched controls. Norms and the probability of diagnosing dementia at diff erent prevalence rates were calculated. To evaluate the ACE's ability to di fferentiate early AD from FTD, scores of the cases diagnosed with dementia with a Clinical Dementia Rating less than or equal to 1 (AD = 56, FTD = 24, others = 20) were compared. Results: Two cut-off values for the ACE compos ite score (88 and 83) were of optimal utility depending on the target popul ation. The ACE had high reliability, construct validity, and sensitivity (9 3%, using 88 as cut-off). Using the lower cut-off of 83, the ACE had a high er sensitivity (82%) and predictive value than the Mini-Mental State Examin ation for a wide range of dementia prevalence. The ACE differentiated AD fr om FTD, and the VLOM ratio (derived using component scores: [verbal fluency + language]/[orientation + memory]) of <2.2 for FTD and >3.2 for AD was hi ghly discriminating. Conclusion: The ACE is a brief and reliable bedside in strument for early detection of dementia, and offers a simple objective ind ex to differentiate AD and FTD in mildly demented patients.