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Effectively diagnosing dementia

Senior Woman In Discussion With Health Visitor At Home
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Alzheimer’s disease (AD) is a progressive disease of the brain characterised by memory impairment and multiple cognitive abnormalities affecting language, behaviour, emotions, judgement and the ability to do complex tasks.1 Current research suggests AD may result from an increase in the production or accumulation of beta-amyloid protein leading to nerve cell damage.2

Approximately 227,360 Australians are living with dementia with the total cost of necessary care per person estimated at over A$58,000 per person.3 An Access Economics report commissioned by Alzheimer’s Australia and published in March 2005 suggests that the number of people with dementia in Australia will be 25% higher by 2050.4

According to Dr Jonathan Foster, a neuropsychologist based at Edith Cowan University and the WA Centre for Alzheimer’s Disease Research & Care, the "demographic time bomb" of an ageing population highlights the increased need for better and earlier diagnosis of dementia.

"If the disease can be identified earlier, then there’s a much better chance of being able to apply a treatment which will at least delay (and potentially treat) the long-term effects of this hugely debilitating illness. Early diagnosis also permits a support framework for the affected person to be established, with time to plan and make appropriate provisions," he said.

This may include allowing the patient to plan future legal and financial requirements while still competent, and allowing for early interventions which may slow the progress of dementia and may reduce the costs of care (e.g. nursing home costs).5 Additionally, early diagnosis may result in better long-term outcomes for caregivers and increase their confidence in and perceived competence of their doctor.5

Clinical benefits of early diagnosis include identifying treatable and reversible causes of dementia (including infection, depression, drugs, hypothyroidism, vascular risk factors and nutritional deficiencies) and commencing pharmacological treatment and cognitive remediation.5 These treatments have the highest probability of being beneficial when commenced early and may save months of cognitive competence.6 Cholinesterase inhibitors have been shown in open label trials to be less effective in slowing the progression of dementia if commencement is delayed.5

Thus, Dr Foster said there was a need for more effective and valid diagnosis methods.


"At the moment, people are diagnosed clinically by exclusion criteria; a definitive diagnosis can’t be made until after the time of death, when the brain can be examined at post mortem… So it’s a probabilistic diagnosis by exclusion at this stage," said Dr Foster.

Approximately 74% of people present to their GP with symptoms of dementia.4 Unfortunately, with the average consultation being 8-11 mins, doctors may not have much time to screen for the disease, and according to some surveys, up to 50% of Alzheimer’s sufferers are not diagnosed, particularly in mild cases. Therefore, it is necessary to have a simple, fast and reliable tool to screen for cognitive impairment.5

Dr Henry Brodaty, Professor of Psychogeriatrics at the Dementia Collective Research Centre at University of New South Wales, has conducted research into the fastest and most efficient ways to screen for Alzheimer’s and found the three most effective were the GP Cog and the Mini-Cog, which are computerised tests, and the Memory Impairment Scale.

The Mini-Cog tool is a 3 minute test which has been found to be one of the most suitable instruments for use in general practice.4 It tests both memory executive function.5 The Mini-Cog tool has a sensitivity and specificity of more than 80% and is simple and fast.5 However, It is not sufficient alone to diagnose dementia. Further history, examination and investigations need to be undertaken. Final diagnosis is usually made by a neurologist, geriatrician or psychogeriatrician.5

quiz iconMini-cog
The Mini-Cog is a 3 minute test which can be used to discriminate between demented and non-demented persons.

The GP Cog, developed by Professor Brodaty and colleagues, is similar to the Mini-Cog. Patients who score poorly in a three-minute computerised test are likely to have Alzheimer’s, while those who score perfectly are not. Only when an intermediate score is achieved do GPs need to take further steps and interview an informant to determine whether the patient has Alzheimer’s.

"We know GPs’ time is a major constraint for them doing screening and testing. A computerised cognitive test such as the GP Cog or Mini Cog takes only 3 minutes – so it’s more efficient, and it gives results that are slightly better than exams currently used by GPs," said Professor Brodaty.

While the majority of patients and caregivers prefer early diagnosis, it is prudent to be aware of and sensitive to the suffering an early diagnosis can cause.4 Patients report increased emotional and financial costs, fear of stigma associated with the disease, anxiety and depression, inability to get life insurance and loss of driver’s licence and other privileges.7


To monitor the progress of dementia, the Dementia Benchmark Checklist is another useful too. Ideally this should be completed by the patient every 6 months. It covers areas such as memory, concentration, ability to do tasks, mood and agitation.

Dementia Benchmark Checklist
Once this checklist is completed the scores will establish a benchmark for all subsequent checklists. Ideally, these should be completed every 6 months.
Click here to complete the Dementia Benchmark Checklist

In conclusion, early screening for dementia may reduce the burden of this disease in Australia. The Mini-Cog has been identified as one of the best screening tools available to GP’s being simple and fast with a high specificity and sensitivity. The Dementia Benchmark Checklist also freely available online is an ideal way to monitor the progress of patients with dementia.

References:

  1. Therapeutic Guidelines Limited, Psychotropic, 2003, Therapeutic guidelines Limited, Australia.
  2. Kumar P, Clark M. Clinical Medicine. 5th Ed. Edinburgh: W.B. Saunders; 2002.
  3. Binod N, Ranmuthugala G, Brown L, Budge M. Modelling costs of dementia in Australia: evidence, gaps and needs. Australian Health Review. Aug 2008; 32(3): 469-87.
  4. Access Economics. Dementia estimates and projections: Access Economics Report 2005. Prepared for Alzheimer’s Australia. Canberra, 2005.
  5. Brodaty H, Low L, Gibson L, Burns K. What is the best dementia screening instrument for General Practitioners to use? American Journal of Geriatric Psychiatry. 2006; 14: 391-400.
  6. Giatuinto S, Parnetti L. Early detection of dementia in clinical practice. Mechanisms of Ageing and Development. 2006; 127: 123-8.
  7. Boustani M, Perkins A, Monahan P, Fox C, Watson L, Hopkins J, et al. Measuring primary care patients attitudes about dementia screening. International Journal of Geriatric Psychiatry. 2008; 23: 812-20.

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Posted On: 23 September, 2008
Modified On: 20 March, 2014

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