Study examines quick and simple 'dementia test'

Behind the Headlines

Tuesday January 14 2014

Would you take a 10-minute dementia test?

Dementia is formally diagnosed using a battery of tests

"Alzheimer's disease: 15-minute test could spot early sign of dementia," reports The Daily Telegraph. The news is based on a US study that examined the so-called Self-Administered Gerocognitive Examination (SAGE) as a screening tool for mental decline.

SAGE assesses a variety of people's mental functions and can be completed using just a pencil and paper almost anywhere – speed and simplicity are often advantageous for screening tests. The SAGE score could help a doctor decide whether to order further tests, or it could be used to see if there are any changes in a person's mental function over time.

How accurate is the SAGE test?

The SAGE test reportedly has a sensitivity of 79% (79% of people with mild cognitive impairment [MCI] will get a positive result, while 21% of people with MCI will get a negative result). It has a specificity of 95% (95% of people without MCI will get a negative result and the other 5% of people without MCI will get a positive result). These values are based on previous studies.

 

This may equate to a positive predictive value of between 15% (assuming that just over 1 in 100 in the whole population has MCI) and 45% (assuming 5 in 100 aged over 60 have MCI). The positive predictive value of a test depends on the proportion of people who have the condition in the population being tested.

 

Statistician Graeme Archer has described some of the problems with predictive values of screening tests in a blog for The Daily Telegraph.

In this study, researchers assessed whether community-based SAGE screening for the over-50s was feasible. They found that they could screen a large number of people in the community using the test. Of those screened, 28.4% were identified as having mental decline based on previously published standards.

However, the researchers did no further testing to determine whether people scoring in the mild cognitive impairment or dementia range had evidence of these conditions. The test also was not compared with other existing cognitive tests.

It is important to note that despite suggestive media headlines, this test alone cannot formally diagnose Alzheimer's disease or any other form of dementia.

As yet, the balance of benefits and harms of screening the general population for mental decline or dementia remains unclear.

If you are worried about your or a friend or relative's memory, talk to your GP and sign up to the Dementia Information Service weekly emails.

 

Where did the story come from?

This cross-sectional study was carried out by researchers from the Ohio State University Wexner Medical Center. The source of funding was not reported.

It was published in the peer-reviewed Journal of Neuropsychiatry and Clinical Neurosciences.

This research was widely covered in the media. Many hailed SAGE as a 15-minute test that could spot Alzheimer's disease.

However, the researchers did not examine how good SAGE was at detecting mild cognitive impairment (mental decline) or dementia. They also did not carry out further tests to confirm the diagnosis of a specific condition, such as Alzheimer's disease.

Instead, the study examined whether it was possible to use SAGE in the community to detect cognitive decline. If successful, it could potentially be used to help identify people who may need to see healthcare professionals for advice or further testing.

 

What kind of research was this?

This study investigated the characteristics and usefulness of the Self-Administered Gerocognitive Examination (SAGE) as a screening test.

SAGE is used to identify people with mild cognitive impairment and dementia in the community. It has questions on six areas:

  • orientation (such as the date)
  • language (verbal fluency and picture naming)
  • reasoning and computation (abstraction and calculation)
  • visuospatial (3D construction and clock-drawing)
  • executive ("modified Trail B", a kind of "dot-to-dot", and other problem-solving tasks)
  • memory

There are four slightly different versions of SAGE, designed to avoid the effects of practice (getting a better score because you've done the same test multiple times) and prevent cheating when it is given to large groups of people at the same time.

People with scores between 22 (maximum score) and 17 are likely to have normal cognition, those with scores of 16 and 15 are likely to have mild cognitive impairment, and people with scores of 14 or less are likely to have dementia.

Doing the test for the first time represents the "baseline" from which changes in score can be monitored.

 

What did the research involve?

The study recruited 1,047 people over the age of 50 from a range of locations through events at senior centres, health fairs, educational talks, independent and assisted living facilities, and via newspaper adverts.

People were given the SAGE test to fill in, which was then collected and graded. Large groups of people sometimes completed the test at the same time.

Administrators would provide people with the score on the spot and gave out written information on the test. People were advised to show their score to their doctor for interpretation and any further screening or tests.

 

What were the basic results?

The average SAGE score was 17.8. On the basis of their SAGE score, 71.6% of those tested had normal cognition, 10.4% had mild cognitive impairment (mild mental decline), and 18% had dementia.

Older age and lower education were associated with lower total SAGE scores.

 

How did the researchers interpret the results?

The researchers described screening people using SAGE as "feasible, practical, reliable, and efficient".

They said: "SAGE is able to rapidly screen large numbers of individuals in the community at the same time because of its self-administered feature and having four interchangeable forms that reduce the temptation of dishonesty.

"In our study, 28.4% of those screened were identified as having cognitive impairment, based on previously published standards for the SAGE test. Finding these individuals through screening can 'start the conversation' about cognitive impairment with their primary care doctors and potentially lead to earlier evaluation, management, and treatments.

"It also potentially makes it easier to find research participants at the early and pre-dementia stages, to evaluate new therapies. Future studies need to compare SAGE with cognitive screening measures that require more administration time," they added.

 

Conclusion

This study examined SAGE as a screening tool. Researchers found that a large number of people could be screened in the community for mental decline using SAGE.

Of those screened, 28.4% were identified as having mental decline based on previously published standards for the SAGE test.

No further testing (for instance, validated cognitive tests or investigations such as brain scans) was performed to determine whether people whose scores suggested that they may have mild cognitive impairment or dementia actually had clinical evidence of these conditions, and the test was not compared with other existing cognitive tests.

It is therefore unclear how accurate and reliable this test may be as an indicator of mild cognitive decline (mental decline) or dementia. Despite suggestive media headlines, this test alone cannot diagnose Alzheimer's or any other form of dementia.

In addition, further studies are required to determine whether there are any benefits or harms in screening the general population for mental decline. Some in the medical profession are troubled by the thought of mass screening for dementia when there are currently few helpful therapeutic options.

If you are worried about your own or a loved one's memory, visit your GP. You may find the NHS Choices Dementia Information Service useful if you or a friend or relative have recently been diagnosed with dementia.

Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter.

Analysis by Bazian

Edited by NHS Choices

Links to the headlines

Alzheimer's disease: 15-minute test could spot early sign of dementia. The Daily Telegraph, January 13 2014

Can you answer these five questions? The 15-minute home test that spots signs of Alzheimer's. Daily Mail, January 13 2014

Self-test could provide an early indication of the onset of dementia. Daily Mirror, January 13 2014

Dementia: 15-Minute Test To Spot Signs Early. Sky News, January 13 2014

Links to the science

Scharre DW, et al. Community Cognitive Screening Using the Self-Administered Gerocognitive Examination (SAGE). Journal of Neuropsychiatry and Clinical Neurosciences. Published online January 13 2014

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