Evaluation of the Addenbrooke's Cognitive Examination-Revised in a routine cognitive outpatient clinic

BackgroundThe Addenbrooke's Cognitive Examination-Revised (ACE-R) is a widely used multidomain cognitive screening instrument. However, its performance in routine cognitive outpatient clinics with heterogeneous, diagnostically unselected populations remains insufficiently characterized.ObjectiveTo evaluate the diagnostic accuracy and clinical utility of ACE-R across the spectrum of cognitive impairment in a real-world cognitive outpatient setting.MethodsThis retrospective observational study included 348 consecutive patients attending a cognitive outpatient clinic. Diagnostic accuracy was assessed using binary and multiclass classification, and longitudinal cognitive trajectories were analysed using multilevel modelling.ResultsACE-R reliably differentiated dementia from non-dementia and distinguished Alzheimer's disease from mild cognitive impairment. Discrimination between subjective cognitive impairment and normal cognition was limited, consistent with the absence of objective cognitive deficits in subjective cognitive impairment. The instrument demonstrated greater sensitivity for cortical dementias than for subcortical conditions. Longitudinal analyses showed significant cognitive decline in Alzheimer's disease.ConclusionsACE-R is a practical and clinically useful screening tool for routine outpatient settings, particularly for dementia detection. However, limited sensitivity in early-stage impairment and restricted ability to differentiate dementia subtypes support its use within a multimodal diagnostic framework rather than as a standalone instrument.