Is the Abbreviated Mental Test Score the best we’ve got?

02 January 2014

Dr Thomas Jackson and Professor John Gladman discuss a recent review of screening tools for dementia in general hospitals.shutterstock_88989310

Thomas Jackson says:

Geriatricians will often diagnose dementia for the first time in hospital as a crisis admission. Here the diagnosis is usually straightforward but we are left with a feeling that the crisis may have been preventable had a diagnosis been made earlier. Dementia is very much a hot topic at the moment. There has been the recent political drive to raise rates of diagnosis through an appeal by the Prime Minister and introduction of a financial incentive to improve dementia detection in hospitals (a Commissioning for Quality Innovation Payment or CQUIN). Getting the diagnosis of dementia right, and in a timely fashion, is important for the patient, their carers and medical professionals looking after them. Diagnosis gives reassurance to patients and carers about worrying symptoms, as well as allowing access to specialised health and social care services. Making the diagnosis in hospital enables healthcare professionals to ensure they get the best care.  However, we need the right tools to help us get things right. 

If we are to embed the best quality dementia care into our everyday practice we need to develop tools and guidelines to help ensure we are delivering best care.  Using simple screening tools leads to the dangers of over-diagnosing dementia, such as the additional worry and burden of unnecessary tests. In hospital, where dementia prevalence is higher than in the community, we need to be using tools to help guide our clinical decisions that reflect that.

Our recent systematic review shows there aren’t many tools available to help screen for dementia in this vulnerable group. Most of the tools we use in practice were developed for the out-patient setting, where the incidence and presentation of dementia is different.

With the Mini-Mental State Examination (MMSE) having licensing problems, the best studied tool is the Abbreviated Mental Test Score (AMTS), with reasonable statistics to support its use  The best test (with the most true results, and the least false positive results), however, would appear to be an informant tool, the Informant Questionnaire of Cognitive Decline in the Elderly (IQCODE). Combining the two tests, with an incorporated delirium screen ends up looking very similar to the 2005 publication Delirious about Dementia  published by the British Geriatrics Society and faculty of Old Age Psychiatry

So, given the increase of frail elderly patients with delirium and dementia in our acute hospitals is it time to come up with new fit for purpose tools, or stick with well recognised tools with renewed confidence in their use?

Professor John Gladman says:

I think the lively debate over screening for dementia has become rather complicated.

Most screening approaches would be used in the community. For older people coming into hospital, a two stage approach is common and felt to be efficient. Typically the AMTS is used as the first step to identify people with cognitive impairment, and then those with cognitive impairment are subject to more  sophisticated diagnostic processes.

This paper shows that the AMTS is moderately useful in identifying people with dementia in this setting, but is less than ideal.

But the issue is not solely about using the hospital as a setting to identify people with dementia. These people are already ill: they need a comprehensive assessment to guide comprehensive care planning, and their care will be influenced by the presence of cognitive impairment, irrespective of diagnosis.

So, we should continue to use simple tests such as the AMTS in hospital patient to identify cognitive impairment, but be aware that without care this will miss some cases of dementia and potentially over-diagnose many more. The uncertainty over the case for screening should not stop us planning and providing comprehensive care.

Dr Thomas Jackson is funded through a joint clinical research fellowship from Research into Ageing, a fund set up and managed by Age UK and the British Geriatrics Society. The opinions expressed here are his own.

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