Addenbrooke's Cognitive Examination (ACE) for the diagnosis and differential diagnosis of dementia

The Addenbrooke's Cognitive Examination (ACE) is reported to be a highly sensitive and specific "bedside" test for the diagnosis of dementia, but large pragmatic studies of its use in day-to-day clinical practice are lacking. This study measured diagnostic accuracy of ACE in a large cohort of consecutive patients referred to a dedicated Cognitive Function Clinic.

Consecutive new referrals over a 3.5-year period were administered the ACE (n=285). ACE scores and subscores (VLOM ratio) were compared to clinical diagnoses of dementia and dementia subtype, established on the basis of widely accepted diagnostic criteria and at least 12-month follow-up.

ACE had good sensitivity, specificity, and positive predictive value for the diagnosis of dementia, with excellent diagnostic accuracy as measured by area under the receiver operating characteristic curve. However, a lower cutoff than that used in the index paper was required for optimum test sensitivity and specificity. ACE VLOM ratio subscore for the differential diagnosis of Alzheimer's disease and frontotemporal dementia proved less accurate.

This study suggests that ACE is useful for the diagnosis of dementia in routine clinical practice but that other instruments may be required for the differential diagnosis of the dementia syndrome.