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EDITORIALS
Towards evidence-based dementia screening in Australia
Zoe Terpening, John R Hodges and Nicholas J Cordato
Effective dementia care depends on early and accurate diagnosis
t is predicted that over the next 40 years there will be a
fourfold increase in the prevalence of dementia in Australia, as
well as considerably more people with milder forms of cognitive
impairment. 1 To date, despite extensive research, no effective
treatment for established dementia is available. As a result,
taskforce policymakers conclude that there is insufficient evidence
at present to warrant routine screening for dementia syndromes. 2,3
However, emerging evidence shows that early non-pharmacological
intervention can improve cognitive outcomes for patients with
milder forms of cognitive impairment and those at risk of
cognitive decline. 4 Early diagnosis also enables patients to plan,
with their caregivers, for the future, and deal with matters such as
enduring power of attorney authorisation, before they lose the
capacity to do so. Over two-thirds of people who notice symptoms
of cognitive decline consult a physician for evaluation. 5 However,
up to 90% of mild cases are missed at the initial primary care
assessment. 6,7 I
So how can we improve early detection of cognitive
impairment, and what evidence base do we have for dementia
screening in Australia?
A diagnosis of dementia relies on a full mental status assessment,
with comprehensive history taking and physical examination. Presently,
detailed neuropsychological testing is the gold-standard tool
for objectively evaluating the magnitude and pattern of cognitive
decline. However, neuropsychological evaluation is costly, timeconsuming
and not generally available as only specialist psychologists
can do it. Consequently, general practitioners and specialist
60 MJA • Volume 194 Number 2 • 17 January 2011
physicians, who evaluate most patients presenting with cognitive
complaints, administer brief screening instruments such as the minimental
state examination (MMSE) to assess cognition. In Australia,
the use of such instruments has been propagated by guidelines for
prescribing acetylcholinesterase inhibitors. The MMSE has many
documented and widely appreciated shortcomings. It lacks diagnostic
specificity and is insensitive to patient variables such as extreme
levels of education, premorbid ability and poor command of
English. 8 It has also been criticised for its unsystematic and atheoretical
construction, and its poor ability to detect milder forms of
cognitive impairment. 8,9
The idea that any brief screening tool would have sufficient
sensitivity and specificity to diagnose dementia is unrealistic. However,
when used as an adjunct to a good clinical history, a more
accurate instrument, particularly one that can be serially administered,
would potentially increase the reliability of diagnosis. A recent
review of screening instruments available for mild cognitive impairment
concluded that there are more useful screening tools than the
MMSE. 10 Some are in use in Australia, including the Addenbrooke’s
Cognitive Examination – Revised (ACE-R); the Alzheimer’s Disease
Assessment Scale — cognitive subscale (ADAS-cog); and the Montreal
Cognitive Assessment battery. In addition, there are other
screening instruments specifically validated for use in Australia,
such as the General Practitioner assessment of Cognition (GPCog)
and Rowland Universal Dementia Assessment Scale (RUDAS).

EDITORIALS
Recently, the ACE-R was validated for use in an Australian
population. 11 The ACE-R, which incorporates the MMSE, has been
shown to have more diagnostic sophistication, with improved
sensitivity and specificity values, than the MMSE alone. This is not
to say that the ACE-R is without limitations. For instance, it cannot
fully assess some aspects of cognitive function (eg, non-verbal
skills). Furthermore, the ACE-R takes on average 16 minutes to
administer and is therefore unlikely to see much uptake by busy
GPs; however, it could be used by nurses working in general
practices. As with all screening tools, clinicians using the ACE-R in
the primary care setting need to be trained to correctly score and
interpret patients’ ACE-R performances.
Development of effective dementia treatments depends on earlier
and more accurate identification of disease. Cognitive screening tests
will continue to evolve, and may in time be replaced with screening
for disease-related biomarkers. However, such diagnostic biomarkers
have yet to be discovered. With the number of people with
dementia growing each year, the lack of adequately validated
diagnostic tools is a serious concern. Empirical investigations to
further evaluate and validate screening instruments for cognitive
impairment are necessary as we strive to develop effective treatments
for all forms of this debilitating disorder.
Competing interests
Nicholas Cordato has received a grant from the Medical Foundation,
University of Sydney, to research Alzheimer’s disease.
Author details
Zoe Terpening, BPsych(Hons), MSc, DClinNeuropsych, Clinical
Neuropsychologist1 John R Hodges, MD, FRCP, FMedSci, Federation Fellow and Professor
of Cognitive Neurology2 Nicholas J Cordato, MB BS, PhD, FRACP, Senior Staff Specialist in
Aged Care 3
1 Ageing Brain Centre, Brain and Mind Research Institute, University of
Sydney, Sydney, NSW.
2 Prince of Wales Medical Research Institute, Sydney, NSW.
3 Department of Aged Care, St George Hospital and Calvary
Rehabilitation and Geriatric Service, Calvary Health Care, Sydney,
NSW.
Correspondence: zoe.terpening@sydney.edu.au
References
1 Access Economics. Keeping dementia front of mind: incidence and
prevalence 2009–2050. 2009. http://www.accesseconomics.com.au/publicationsreports/getreport.php?report=214&id=272
(accessed Nov
2010).
2 United Kingdom National Screening Committee. Policy database.
Alzheimer’s disease. http://www.screening.nhs.uk/alzheimers (accessed
Dec 2010).
3 Boustani M, Peterson B, Harris R, et al. Screening for dementia. June
2003. Agency for Healthcare Research and Quality, US Department of
Health and Human Services. (AHRQ contract no. 290-97-0011.) http://
www.ahrq.gov/downloads/pub/prevent/pdfser/dementser.pdf (accessed
Dec 2010).
4 Naismith S, Glozier N, Burke D, et al. Early intervention in cognitive
decline: is there a role for multiple medical or behavioural interventions?
Early Intervent Psychiatry 2009; 3: 19-27.
5 Wilkinson D, Stave C, Keohane D, Vincenzino O. The role of general
practitioners in the diagnosis and treatment of Alzheimer’s disease: a
multinational survey. J Int Med Res 2004; 32: 149-159.
6 Boustani M, Peterson B, Hanson L, et al. Screening for dementia in
primary care: a summary of the evidence for the US Preventive Services
Task Force. Ann Intern Med 2003; 138: 927-937.
7 Valcour VG, Masaki KH, Curb JD, Blanchette PL. The detection of
dementia in the primary care setting. Arch Intern Med 2000; 160: 2964-
2968.
8 Tombaugh TN, McIntyre NJ. The mini-mental state examination: a
comprehensive review. J Am Geriatr Soc 1992; 40: 922-935.
9 Zarit SH, Blazer D, Orrell M, Woods B. Throwing down the gauntlet: can
we do better than the MMSE? Aging Ment Health 2008; 12: 411-412.
10 Lonie JA, Tierney KM, Ebmeier KP. Screening for mild cognitive impairment:
a systematic review. Int J Geriatr Psychiatry 2009; 24: 902-915.
11 Terpening Z, Cordato N, Hepner I, et al. Utility of the Addenbrooke’s
Cognitive Examination — Revised for the diagnosis of dementia syndromes.
Australasian J Ageing 2010. doi: 10.1111/j.1741-
6612.2010.00446.x [17/08/10] ❏
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