Researchers at Addenbrook’s Hospital in Cambridge published a study on bmj.com in which they explain their design and evaluation of a new cognitive test for detecting Alzeimer’ disease called TYM (“test your memory”) which is considered quicker and more precise than many existing tests, and which can also help diagnose early dementia.
It is extremely important to develop early detection of dementia in order to administer a useful treatment. But as of today there is still no short cognitive test that is quick to use, that can examine various skills, and that is sensitive to Alzheimer’s disease. The reason for the importance of this early diagnosis is that today, an estimated 24 million people worldwide have dementia, and this figure will double every twenty years.
The TYM is a simple but useful sequence of 10 tasks which includes the following:
• The ability to copy a sentence.
• Semantic knowledge.
• Calculations.
• Verbal fluency.
• Recall ability.
Each task is scored with a maximum of 50 points available.
The test is specifically intended for the supervisors to hardly get involved, and also designed friendly enough for non-specialist use.
The trial was completed by two types of individuals. The first group was a total of 540 participants (controls) all in good physical shape aged 18 to 95 years with no history of neurological disease, memory problems or brain injury. The other group consisted of 139 patients with a confirmed diagnosis Alzheimer’s or mild cognitive impairment.
The TYM test was measured against two frequently used bedside cognitive tests: 1) The mini-mental state examination 2) The Addenbrooke’s cognitive examination.
The mini-mental state examination has been used for over thirty years by The National Institute for Health and Clinical Excellence (NICE) as the most reliable short cognitive test for coherent decision on which patients should de treated with drugs and monitor their response to the drug treatment.
Controls completed the test in a common average time of not more than five minutes and received an average score of 47 out of 50. Patients with Alzheimer’s disease achieved much poorer scores with an average of 33 points out of 50. Patients with mild cognitive impairment scored an average of 45 out of 50.
The results of the average TYM score remained steady between the ages of 18 and 70 years, with a small decline in performance after this age. Scores did not differ between men and women or by geographical background, suggesting that education and social class would have only mild effects on the TYM score.
Important conclusions on the TYM test resulted in the detection of 93% of the patients with Alzheimer’s disease compared to the mini-mental state examination that could only detect a low 52%.
This concludes that the TYM is a more efficient method for detecting mild Alzheimer’s disease. It is also important to mention that the TYM examines a broader range of cognitive domains in a very short period of time.
The Adenbrooke’s cognitive examination seems also to be a good method in detecting mild Alzeimer’s disease. The cognitive domains tested are similar to those of the TYM, but a big inconvenience to Adenbrooke’s is that it takes much longer to administer and score with an average of 20 minutes.
As a conclusion the authors mention that the TYM is an influential and valid screening test for the detection of Alzheimer’s disease.
Consultant physician Claire Nicholl explains in a complementary editorial: “The usefulness of screening tests varies according to the clinical setting.”
“If the test your memory test is to be adopted more widely it must be validated in a range of settings and different populations”, she adds. Until then, the most essential point is that clinicians should identify a test that corresponds to their clinical setting. They should develop their skills in its use to improve the identification of patients with early dementia.
“Self administered cognitive screening test (TYM) for detection of Alzheimer’s disease: cross sectional study”
Jeremy Brown, consultant neurologist, George Pengas, clinical research fellow, Kate Dawson, research nurse, Lucy A Brown, honorary research assistant, Philip Clatworthy, clinical research fellow
BMJ 2009;338:b2030
Written by Stephanie Brunner (B.A.)