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Topic of the Month February: New Diagnostic Methods
Recognising the Early Stages of Alzheimer‘s Disease
Recognising the early stage of
Alzheimer's disease offers a
glimmer of hope;© panther-
Next to psychometric tests and laboratory tests, this problem is increasingly being solved by cerebral imaging, an illustration of the brain using computer tomography or magnetic resonance imaging.
At the moment, many things are changing drastically in Alzheimer’s diagnostics. These days there is a wide range of procedures available for identifying this specific form of dementia – and others will follow: new imaging procedures and biochemical detection methods such as biomarkers. The fact that this disease sparks a lot of research interest is not surprising, given that today it is the most common type of dementia in old age. According to current estimates there are presently about 1.3 million dementia patients living in Germany. Due to the increased aging of the population, until 2040 a significant increase in patients is being expected. Especially in China at that point in time, approximately 26 million people are said to be suffering from dementia. Researchers also expect similar developments in other Asian and South American countries. However, a solution to stop the disease or to prevent it still does not exist.
Early diagnostic methods – for what?
Searching for new diagnostic methods could initially be perceived as a contradiction. You might ask yourself what the point of developing new diagnostic methods might actually be, if a cure for the disease is beyond our reach in the foreseeable future due to a number of different reasons. Yet especially recognizing the early stage of this disease offers a glimmer of hope – drugs for example can delay the progression at least in the early stages. One other reason: all too often Alzheimer’s is confused with other diseases and is being treated the wrong way or is not being diagnosed in the first place. Basic diagnostic methods are oftentimes not enough to reach an exact diagnosis.
Doctor Stefan Klöppel, a physician at the Freiburg Brain Imaging Center, Section of Geriatric Medicine and Gerontology, has researched a new diagnostic method for a long time. Together with his team, he wants to counteract this trend by having developed an automated diagnostic procedure for dementia. In this instance, a computer program and not a radiologist or a neuroradiologist interprets routine MRI brain images, among others for the following reason: “Our study of admittedly previously selected patients revealed: only radiologists who are specialized and work in neurodegenerative disease clinics diagnose just as well as the automated MRI technique. All other radiologists did not diagnose Alzheimer’s as precisely,“ Klöppel knows.
The automated MRI technique can then be passed on to the private medical practitioner. “If a general practitioner suspects his patient might have dementia, he refers him/her to a radiologist. The responses from many radiologists remain relatively nonspecific, since they simply have less experience. For instance, they state loss of brain volume without it being clear whether this loss exceeds what’s typical for this age group and whether it provides a clue to the disease. An automated diagnostic procedure would assist to specify the diagnostic findings,“ explains Klöppel.
And so physicians have experienced many times that people who are initially suspected of being affected, desperately request more information. They want to know for sure which disease they actually have. The newly developed technique for an automated diagnosis helps to make an accurate diagnosis more quickly. A computer program learns based on different atrophy patterns to distinguish between those seen in dementia and those seen in healthy age. “It compares the index case, the patient who comes to the neurodegenerative clinic, with the model cases“, Klöppel continues.
A new computer procedure could specify and accelerate the diagnosis of Alzheimer’s;
A diagnosis in many steps
Patients who are suspected of having Alzheimer’s continue to go through the classic clinical diagnostics process. The first step is a self-anamnesis and assessment by a family member. During the next step, other diseases are being eliminated before conducting an imaging examination. In addition, there always needs to be some testing, a simple exam of brain functions, to reach a comparison with the healthy average population. Professor Supprian, Head of Department of Geriatric Psychiatry of the LVR Clinic Center Düsseldorf, Germany, explains: “A dementia diagnosis is made up of several components, the anamnesis, a physical examination, neuropsychological testing, imaging and laboratory tests. There is no single procedure to determine dementia – there is no individual laboratory parameter in particular. “
Different screening tests have long since been procedures that are being used to diagnose Alzheimer‘s. But in the future, new developments such as neuropsychological tests are meant to diagnose early disease stages even better. “The so-called CERAD psychological test battery is very popular here in Germany“, says Supprian. “It’s is becoming apparent that there will soon be further tests with which we can determine the early stages of Alzheimer’s and Dementia. Among them is the “California Verbal Learning Test (CVLT)“ for example or the “Free and Cued Selective Reminding Test (FCSRT)“. These are most notably procedures that have so far only been used in the Anglo-American area. Right now, corresponding standards are being developed in Germany. “
The research for a computer program that detects Alzheimer’s is thus within reach of becoming practice. That said, Klöppel and his team admit: “To implement this technique you need a specific question, for instance whether this is dementia due to Alzheimer’s or due to the normal aging process? Another question might be: Is this Alzheimer’s disease or is this frontal lobe dementia?“ Without an exact medical classification you cannot make a successful diagnosis with this technique.
In contrast, according to many experts and despite numerous euphoric press reports, the success of biomarkers in Alzheimer’s diagnostics remains subject to research for the time being. It is rather unlikely that biomarkers replace current methods in routine diagnostics in the next few years.
Time will tell which new diagnostic techniques will find their way into practice as standard procedures for diagnosing Alzheimer’s. Above all however, new diagnostics techniques should pursue one goal – they should become easier and more exact. Supprian is certain: “In the future comprehensive care with this examination technique seems definitely possible. I expect that it will develop into a standard practice in the next years.“
Diana Posth (Translated by Elena O'Meara)