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Test type: Concentration

Can't see the wood for the trees? Is your perceptual acuity what it used to be? Try this test to find out.

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Find out what drawing pentagons tells us about Alzheimer's disease?

In this task, when you mentally compare complex images to one another you are using your brain's visuospatial processing skills. A task similar to this is used in the Mini Mental State Examination (MMSE), a simple paper and pencil tool for doctors to assess cognitive function. In the MMSE, instead of comparing images of pentagons, the patient is asked to draw them from memory. This task can help to diagnose Alzheimer's disease in some patients. A common and early sign of Alzheimer's disease is impaired visuospatial processing (particularly in memory tasks) and, as a result, those suffering with the disease tend to perform poorly at this task.


Alzheimer's disease is a form of dementia. Patients with Alzheimer's disease suffer from a general decline in mental abilities, memory loss and language problems, as well as confusion, irritability and mood swings. The cause of this disease is unknown, but is closely associated with 'plaques' and 'tangles' in neural brain fibres. Scientists in many research institutions, including the MRC Cognition and Brain Sciences Unit in Cambridge, have been trying to work out how the brain changes as a result of Alzheimer's disease. For example, when undertaking visuospatial memory tasks, we have found that Alzheimer's patients do not compensate by engaging additional brain regions, but rather, show greater engagement of those same areas that are activated by healthy volunteers. We believe that this increased brain activation may be a result of Alzheimer's patients finding these tasks much more difficult than healthy volunteers (Gould et al, 2006).

Together with our colleagues in the Departments of Experimental Psychology and Psychiatry, Cambridge we have also looked at whether medication for Alzheimer's disease can produce beneficial effects on cognitive function. We gave tests similar to some of those on this website to Alzheimer's disease patients who were taking the drug tetrahyrdoaminoacridine (THA) and found that this treatment produced its cognitive benefits through improving attention (Sahakian et al,1993). We have now created a website to make many of our cognitive tests available to pharmaceutical companies, who can use them to assess cognitive function when developing new medicines.

-Gould, R.L., Arroyo, B., Brown, R.G., Owen, A. M., Bullmore, E.T., Howard, R.J. (2006). Brain mechanisms of successful compensation during learning in Alzheimer disease. Neurology. 67 1011-1017 View Abstract
-Sahakian, B.J., Owen, A.M., Morant, N.J., Eagger, S.A., Boddington, S., Crayton, L., Crockford, H.A., Crooks, M.M., Hill, K. Levy, R.(1993). Further analysis of the effects of tetrahydroaminoacridine (THA) in Alzheimer's disease on attentional and mnemonic function using CANTAB. Psychopharmocology (Berl), 110(4), 395-401. View Abstract

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