The diagnostic accuracy of Addenbrooke’s Cognitive Examination (ACE) as a brief ‘bedside’ cognitive screening instrument has led to its widespread adoption. Nonetheless, certain weaknesses have been identified in the ACE, prompting the development of the Addenbrooke’s Cognitive Examination-Revised (ACE-R). The ACE-R has been reported to have excellent sensitivities and specificities (>0.8) for the diagnosis of dementia at cut-off scores of 88/100 and 82/100 in the setting of a university hospital clinic.
- Maximum score of 100 weighted as follows:
– Orientation 10
– Attention 8
– Memory 35
– Verbal fluency 14
– Language 28
– Visuospatial ability 5
- Raw scores are used for all items except for verbal fluency where a scaled scoring system for the letter and category fluency is utilized. (1)
- Cut off score 88 or 83 (88 has higher sensitivity though). (1)
- Able to differentiate between Alzheimer’s Disease (AD) and Frontotemporal Dementia (FTD) using VLOM ratio – if >3.2 likely AD, if <2.2 likely FTD. (1)
Clinical Advantages of the ACE-R
- Incorporates the questions on the MMSE and expands on the domains of memory, language and visuospatial concepts and adds tests of verbal fluency. (1)
- Unlike other assessments (eg. CAMDEX or DRS) does not require specialized equipment or trained assessors. (1)
- 15-20 minutes to administer. (4)
- Sensitive to the early stages of Alzheimer’s (amnestic syndromes) and isolated frontal or linguistic deficits found in early frontotemporal dementia ie. Able to differentiate between AD and FTD, and in early stages of the disorders. (1)
- Able to distinguish between patients with progressive degenerative disorders and those with affective disorders (eg. Major Depression.) The affective groups showed very little impairment in the total ACE scores, only mild deficits in memory and verbal fluency. (4)
- Can detect cognitive impairment in atypical parkinsonian syndromes (Progressive Supranuclear Palsy, Multiple System Atrophy, Corticobasal Degeneration), opposed to MMSE, which cannot. Is as sensitive as DRS for this population. (3)
Clinical Disadvantages of ACE-R
- Paucity of tests of executive functions. (2)
- Some questions are associated withUKand countries with similar government systems (eg. asks for name of prime minister, leader of opposition.) (2)
- High internal consistency – all its component scores contribute to the measurement of cognitive functions and correlate well with the composite score, which in turn determines the presence or absence of dementia. (1)
- Construct validity was best for memory and verbal fluency showing good concordance with standard neuropsychological tests. (1)
- Good construct validity for the diagnosis of dementia and had a high sensitivity, even with a lower cut-off score of 83. (1)
- Detected dementia in 79% of patients – a third more than the MMSE when a cut-off score of 83 was used. And sensitivity of 93% when the cut-off of 88 is used. (1)
- Particularly sensitive in the detection of FTD – nearly doubled the detection rate when compared with the MMSE. (1)
- Age, level of education or gender does not influence the predictive outcome, compared to the MMSE where both age and gender have influential power. (1)
(1) Mathuranath, P.S; Nestor P.J; Berrios, G.E; Rakowicz, W. & Hodges, J.R. (2000) A brief cognitive test battery to differentiate Alzheimer’s disease and frontotemporal dementia. Neurology Vol 55 Issue 11, 1613-1620.
(2) Cummings, J. (2000) New tests for dementia. Neurology Vol 55 Issue 11, 1601-1602.
(3) Bak, T.H.; Rogers, T.T.; Crawford, L.M.; Hearn, V.C.; Mathuranath, P.S. & Hodges, J.R. (2005) Cognitive beside assessment in atypical parkinsonian syndromes. Journal of Neurology, Neurosurgery and Psychiatry Vol 76, 420-422.
(4) Dudas, R; Berrios, G. & Hodges, J. (2005) The Addenbrooke’s Cognitive Examination (ACE) in the differential diagnosis of early dementias versus affective disorder. American Journal of Psychiatry Vol 13 Issue 3, 218-226.