A multitude of systematic reviews on dementia diagnosis

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A few weeks ago, I wrote a Mental Elf blog about a Cochrane Systematic Review looking at how effective the Mini-Cog is to diagnose dementia in community settings. I criticised the fact that the authors only looked at three studies. This was the result of their narrow inclusion criteria (only community settings).

It turns out, Cochrane has a whole raft of new systematic reviews on dementia diagnosis tools, some of them only at the protocol stage.

It’s critical that we improve dementia diagnosis rates, so that we can provide people with dementia medication and non-pharmacological interventions as early as possible, to prolong their levels of independence. That’s why it is one of the top priorities in the Prime Minister’s Challenge on Dementia 2020, and has even started to attract a financial incentive for general practitioners.

The Mini-Mental State Examination (Folstein et al., 1975) used to be the main tool for diagnosing cognitive problems. However, with practitioners and researchers being asked to pay for using the MMSE, and with the MMSE being less sensitive to early dementia and mild cognitive impairment, alternatives are being sought and there are now a vast number of diagnostic tools available.

In this blog, I am going to provide a short overview of the systematic reviews on dementia diagnosis tools, and those currently in the pipeline and at the protocol stage only. With so many reviews, you might like to take a look at some individually to get a better understanding of this area! (see links to the full-text at the end of this blog).

The vast number of dementia diagnostic tools available

The vast number of  diagnostic tools available mean that clinicians have considerable choice when deciding how to diagnose dementia and mild cognitive impairment.

The reviews

Status Study Diagnostic tool Setting
Published 1. Fage et al, 2015 Mini-Cog Community
Published 2. Harrison et al, 2014 IQCODE Primary care
Published 3. Quinn et al, 2014 IQCODE Community
Published 4. Harrison et al, 2015 IQCODE Secondary care
Published 5. Arevalo-Rodriguez et al, 2015 MMSE Any
Protocol 6. Seitz et al, 2014 Mini-Cog Primary care
Protocol 7. Chan et al, 2014 Mini-Cog Secondary care
Protocol 8. Creavin et al, 2014 MMSE Community and primary care

Mini-Cog

Comparing the Mini-Cog to other brief measures of global cognition, such as the Mini-Mental State Examination (MMSE), the Montreal Cognitive Assessment (MoCA) and the Addenbrooke’s Cognitive Examination III (ACE-III), the Mini-Cog appears too brief to be truly reliable in assessing dementia.

In my last blog, I looked at the review on the Mini-Cog and its limitations, for once, only three studies were included, and all of these were from the same authors having developed the tool (Fage et al., 2015). This made me question the restriction on the setting. To date, we can’t tell whether the authors should have merged all three reviews together, as two reviews on the Mini-Cog are still outstanding (Chan et al., 2015; Seitz et al., 2015).

Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE)

The Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE) is a frequently used tool to provide a dementia diagnosis based on informant information about cognitive and everyday activity problems over the past 10 years.

Similarly to the reviews on the Mini-Cog, it is surprising to see that the same three settings were split. This is because Harrison et al.’s (2014) review resulted in one included paper, and Quinn et al.’s (2014) review resulted in 10 inclusions. Understandably, little can be generalised from one paper, but Quinn et al. (2014) recommend that the IQCODE does not suffice as a measure on its own. Harrison et al. (2015) found that of the 13 included studies in secondary care settings, the ICQODE was significantly more accurate in hospital settings than in memory clinics. Still, the 24 papers could have been all included in one review and potentially created a greater statement.

Mini-Mental State Examination (MMSE)

The MMSE is a long-established tool to measure cognition in dementia. It is a quick tool that lasts about 10-15 minutes to administer, and asks people to tell the time, location, and remember words, amongst other things.

Arevalo-Rodriquez and colleagues (2015) found 11 studies in total that looked at the diagnostic accuracy of the MMSE in people with mild cognitive impairment, a frequent pre-stage of dementia, to dementia. The MMSE was shown to be between 23-76% sensitive, and between 40-94% specific in diagnosing dementia. These are large variations, and with the authors concluding that the MMSE was not found to be important as a stand-alone diagnostic tool, it also questions the sensisitivity and specificity of the MMSE in mild cognitive impairment.

It will be interesting to see the results of Creavin et al.’s (2014) review on the diagnostic accuracy in people aged 65 and over. Will the quality of diagnosis rates equally vary?

Summary

Looking at all the reviews jointly, not individually, it appears that there has been a strong emphasis on setting. However, with several reviews still being currently completed, it is difficult to understand the reasoning behind this separation, especially when the completed reviews sometimes show low numbers of included trials.

There are many more cognitive screening tools for dementia out there. What about a Cochrane review on the Montreal Cognitive Assessment or the Addenbrooke’s Cognitive Examination III or revised? I’d be happy to be a part of this, but maybe without the setting specification?

The decision to split the reviews into community, primary care and secondary care settings resulted in some reviews having very few studies to analyse.

The decision to split the reviews into community, primary care and secondary care settings resulted in some reviews having very few studies to analyse.

Links

Published reviews

1. Fage BA, Chan CCH, Gill SS, Noel-Storr AH, Herrmann N, Smailagic N, Nikolaou V, Seitz DP. (2015) Mini-Cog for the diagnosis of Alzheimer’s disease dementia and other dementias within a community setting. Cochrane Database of Systematic Reviews 2015, Issue 2. Art. No.: CD010860. DOI: 10.1002/14651858.CD010860.pub2

2. Harrison JK, Fearon P, Noel-Storr AH, McShane R, Stott DJ, Quinn TJ. (2014) Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE) for the diagnosis of dementia within a general practice (primary care) setting. Cochrane Database of Systematic Reviews 2014, Issue 7. Art. No.: CD010771. DOI: 10.1002/14651858.CD010771.pub2

3. Quinn TJ, Fearon P, Noel-Storr AH, Young C, McShane R, Stott DJ. (2014) Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE) for the diagnosis of dementia within community dwelling populations. Cochrane Database of Systematic Reviews 2014, Issue 4. Art. No.: CD010079. DOI: 10.1002/14651858.CD010079.pub2

4. Harrison JK, Fearon P, Noel-Storr AH, McShane R, Stott DJ, Quinn TJ. (2015) Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE) for the diagnosis of dementia within a secondary care setting. Cochrane Database of Systematic Reviews 2015, Issue 3. Art. No.: CD010772. DOI: 10.1002/14651858.CD010772.pub2.

5. Arevalo-Rodriguez I, Smailagic N, Roqué i Figuls M, Ciapponi A, Sanchez-Perez E, Giannakou A, Pedraza OL, Bonfill Cosp X, Cullum S. (2015) Mini-Mental State Examination (MMSE) for the detection of Alzheimer’s disease and other dementias in people with mild cognitive impairment (MCI). Cochrane Database of Systematic Reviews 2015, Issue 3. Art. No.: CD010783. DOI: 10.1002/14651858.CD010783.pub2

Protocols (reviews in progress)

6. Seitz DP, Fage BA, Chan CCH, Gill SS, Herrmann N, Smailagic N, Nikolaou V. Mini-Cog for the diagnosis of Alzheimer’s disease dementia and other dementias within a primary care setting (Protocol). Cochrane Database of Systematic Reviews 2014, Issue 12. Art. No.: CD011415. DOI: 10.1002/14651858.CD011415

7. Chan CCH, Fage BA, Smailagic N, Gill SS, Herrmann N, Nikolaou V, Seitz DP. Mini-Cog for the diagnosis of Alzheimer’s disease dementia and other dementias within a secondary care setting (Protocol). Cochrane Database of Systematic Reviews 2014, Issue 12. Art. No.: CD011414. DOI: 10.1002/14651858.CD011414

8. Creavin ST, Noel-Storr AH, Smailagic N, Giannakou A, Ewins E, Wisniewski S, Cullum S. Mini-Mental State Examination (MMSE) for the detection of Alzheimer’s dementia and other dementias in asymptomatic and previously clinically unevaluated people aged over 65 years in community and primary care populations (Protocol). Cochrane Database of Systematic Reviews 2014, Issue 6. Art. No.: CD011145. DOI: 10.1002/14651858.CD011145.

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Clarissa Giebel

Clarissa is currently a Research Fellow at the University of Liverpool. Her research focuses on enabling people with dementia staying at home for as long as possible, whilst addressing potential health inequalities in accessing the right care. She is currently leading the first Covid-19 dementia study in the UK, exploring the effects of social service closures on the lives of people with dementia and unpaid carers. In her role as postdoctoral research associate at the NIHR ARC NWC, Clarissa is the Principal Investigator on a number of dementia and health inequalities projects. This includes a European Alzheimer's Society funded project into health inequalities in dementia care access in England and the Netherlands, also collecting Young Onset dementia specific data in Australia. Further funded international collaborations in dementia care include Colombia and Chile. She is also involved in the North West Coast Household Health Survey, looking at health inequalities in health service usage across the population. In addition, Clarissa is leading a care home collaboration, where she works jointly with colleagues from the Netherlands on implementing changes to a local Liverpool-based care home and developing a UK Dementia Village. Additional collaborations and projects include working with the Brain Charity evaluating social support groups for people with dementia, and with the Liverpool House of Memories to look into evaluating their intervention for family carers of people living with dementia and care professionals, and trying to roll the intervention out to other neighbourhoods.

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