What Are The 7 Stages Of Alzheimers Disease
Scientists Develop Simple Blood Test For Early Detection Of Alzheimer’s Disease
- Date:
- Hong Kong University of Science and Technology
- Summary:
- An international research team has developed a simple but robust blood test from Chinese patient data for early detection and screening of Alzheimer’s disease with an accuracy level of over 96%.
An international research team led by HKUST has developed a simple but robust blood test from Chinese patient data for early detection and screening of Alzheimer’s disease for the first time, with an accuracy level of over 96%.
Currently, doctors mainly rely on cognitive tests to diagnose a person with AD. Besides clinical assessment, brain imaging and lumbar puncture are the two most commonly used medical procedures to detect changes in the brain caused by AD. However, these methods are expensive, invasive, and frequently unavailable in many countries.
“With the advancement of ultrasensitive blood-based protein detection technology, we have developed a simple, noninvasive, and accurate diagnostic solution for AD, which will greatly facilitate population-scale screening and staging of the disease,” said Prof. Nancy Ip, Morningside Professor of Life Science and the Director of the State Key Laboratory of Molecular Neuroscience at HKUST.
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How Biomarkers Help Diagnose Dementia
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Biomarkers are measurable indicators of whats happening in the body. These can be found in blood, other body fluids, organs, and tissues. Some can even be measured digitally. Biomarkers can help doctors and researchers track healthy processes, diagnose diseases and other health conditions, monitor responses to medication, and identify health risks in a person. For example, an increased level of cholesterol in the blood is a biomarker for heart attack risk.
Before the early 2000s, the only sure way to know whether a person had Alzheimers disease or another form of dementia was after death through autopsy. But thanks to advances in research, tests are now available to help doctors and researchers see biomarkers associated with dementia in a living person.
The different types of biomarkers for dementia detection and diagnosis are outlined below. When combined with other tests, these biomarkers can help doctors determine whether a person might have or be at risk of developing Alzheimers or a related dementia. However, no single test can alone diagnosis these conditions. Biomarkers are only part of a complete assessment. Read more about diagnosing dementia.
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Firstly What Is Gfap Why Is It Important
GFAP originates from the glial cells in the central nervous system, and its increased levels reflect brain atrophy and neuroinflammation. Brain-derived biomarkers are currently mainly measured from the cerebrospinal fluid of the patients.
However, the new study now indicates that ultrasensitive single molecule array is a method, which allows reliable detection of GFAP also from blood samples. This is much more practical and convenient for the patients and the health care system because it allows wider use of biomarker measurements in clinical work.
Right now, scientists are looking for suitable blood-based biomarkers.
Who Can Diagnose Dementia
Visiting a primary care doctor is often the first step for people who are experiencing changes in thinking, movement, or behavior. However, neurologists doctors who specialize in disorders of the brain and nervous system are often consulted to diagnose dementia. Geriatric psychiatrists, neuropsychologists, and geriatricians may also be able to diagnose dementia. Your doctor can help you find a specialist.
If a specialist cannot be found in your community, contact the nearest medical school neurology department for a referral. A medical school hospital also may have a dementia clinic that provides expert evaluation. You can also visit the Alzheimers Disease Research Centers directory to see if there is an NIA-funded center near you. These centers can help with obtaining a diagnosis and medical management of conditions.
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Detecting Alzheimers Gets Easier With A Simple Blood Test
New assays could reduce the need for costlier, more invasive brain scans and spinal fluid measures
When a patient complains of forgetfulness, a neurologist might not know immediately whether it results from normal aging, reduced blood flow to the brainor, more ominously, Alzheimers disease. For much of the past century, a definitive Alzheimers diagnosis could only be made during an autopsy. Brain imaging and spinal fluid tests now make it possible to spot the disease in patients even before the initial symptoms appear. But these invasive tests are expensive and generally limited to research settings that are not part of routine care for the millions of people suffering from the most common neurodegenerative disorder.
An era in which an Alzheimers diagnosis can begin in a doctors office is now arriving. Advances in technologies to detect early signs of disease from a blood sample are helping doctors to identify the memory-robbing disorder more accurately and to screen participants more quickly for trials of potential treatments for the more than five million people in the U.S. afflicted with Alzheimers.
The development of a blood-based test for Alzheimers disease is just phenomenal, says Michelle Mielke, a neuroscientist and epidemiologist at the Mayo Clinic. The field has been thinking about this for a very long time. Its really been in the last couple of years that the possibility has come to fruition.
Assessment For Dementia Usually Includes The Following:
Personal history
The doctor usually spends some time discussing your medical history and gathering information about your changes in memory and thinking.
Physical examination and laboratory tests
The symptoms of dementia can be due to a number of other possible causes, such as vitamin deficiency, infection, metabolic disorders and side effects from drugs.
These other causes are often easily treated.
Therefore, an early step in diagnosing dementia is to rule out these causes through a physical examination, blood tests and urine tests.
Routine laboratory tests used in the diagnosis of dementia include:
- Blood tests to investigate:
- Drug interactions and dosing problems
Cognitive testing
Cognitive tests are used to measure and evaluate cognitive, or thinking, functions such as memory, concentration, visual-spatial awareness, problem solving, counting and language skills.
Most doctors use short cognitive screening tests when assessing these functions. If more detailed testing is required you will be referred to a neuropsychologist a psychologist specialising in the assessment and measurement of cognitive function.
Cognitive tests are vital in the diagnosis of dementia and are often used to differentiate between types of dementia. They can also be used to assess mood and may help diagnose depression, which can cause symptoms similar to those of dementia.
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How Effective Is The Blood Test
C2N reported that they used the Preclivity AD on 168 people. They then compared the results with those of PET scans.
When PET scans showed high amounts of amyloid-beta the blood test agreed 92% of the time.
If there was no amyloid shown after a PET scan, the blood test also gave similar results 77% of the time.
Who Can Benefit From Precivity Ad And How It Works
Precivity AD is designed for persons between the ages of 60-91. A prescribing physician will ship the blood samples of the person they are treating to be analyzed at C2Ns lab.
The results are normally sent back within ten business days.
A proprietary algorithm is used to calculate the results integrating the age of a person with beta-amyloid measurements and another protein known as apolipoprotein E which influences the risk of Alzheimers disease.
The results of the blood test are supposed to enhance the accuracy of clinical diagnosis by distinguishing Alzheimers dementia from memory loss that is brought about by other medical conditions.
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What Are The Different Types Of Dementia
Various disorders and factors contribute to the development of dementia. Neurodegenerative disorders result in a progressive and irreversible loss of neurons and brain functioning. Currently, there are no cures for these diseases.
The five most common forms of dementia are:
- Alzheimers disease, the most common dementia diagnosis among older adults. It is caused by changes in the brain, including abnormal buildups of proteins, known as amyloid plaques and tau tangles.
- Frontotemporal dementia, a rare form of dementia that tends to occur in people younger than 60. It is associated with abnormal amounts or forms of the proteins tau and TDP-43.
- Lewy body dementia, a form of dementia caused by abnormal deposits of the protein alpha-synuclein, called Lewy bodies.
- Vascular dementia, a form of dementia caused by conditions that damage blood vessels in the brain or interrupt the flow of blood and oxygen to the brain.
- Mixed dementia, a combination of two or more types of dementia.
Discuss Test Results With A Doctor
Dont assume that the test results are equal to a diagnosis of any kind.
The SAGE test is a screening tool that helps doctors detect early signs of cognitive impairment that are typically not noticeable during a normal office visit.
When the test is repeated over time, doctors can watch for changes in cognitive ability. Being able to measure changes helps them detect and treat health conditions early.
Thats why its important to bring the completed test to the doctor to have it reviewed. If there are signs of cognitive impairment, they may recommend further testing.
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How The Blood Test For Dementia Works
Also known as the Precitivity AD, the C2N test or blood test for dementia uses mass spectrometry. An analytic technique used to detect specific beta-amyloid protein fragment that is one of the most common hallmarks of Alzheimers.
The beta-amyloid proteins normally accumulate and form plaques which can be seen on the brain 2 decades after an individual starts to notice they have memory issues.
The levels of beta-amyloid start to decline in the surrounding fluids as the plaques continue to build up in the brain. These changes can be measured in spinal fluid samples.
It is also possible to measure them in the blood where beta-amyloid concentrations are usually lower.
PrecivityAD is one of the first blood tests for Alzheimers that could enable early detection of the neurodegenerative illness.
HOPEFULLY, decades before the first symptoms appear.
Demographics And Experimental Design
Participants were classified as PiB and PiB+ groups. The demographic details are shown in Table . The PiB+ group had significantly higher cerebral amyloid deposition than the PiB group . All comparative analyses were conducted for the comparison between PiB and PiB+. Our experimental design is shown in Fig. . First, to narrow down the final targets from the list of all BTFs , the following BTFs were excluded: those with p> 0.2 in Pearsons correlation test abundant proteins such as albumin blood cell numbers those with problems of multicollinearity sex hormones, as they could greatly vary between men and women and those with p> 0.1 in Pearsons correlation test, even after the exclusion of outliers. Finally, four candidate BTFs remained , alanine aminotransferase , and free T3) . These four candidates were finally tested by Pearsons correlation analysis, independent t test, and logistic regression followed by ROC curve analysis . Furthermore, these candidates were statistically combined with our previously identified biomarker assay panel , including four plasma protein markers, galectin-3 binding protein , beta-amyloid 140 , angiotensin-converting enzyme, and periostin , to improve the discrimination power for the comparison of PiB and PiB+ .
Table 1 Demographic data of the participants .
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Dominantly Inherited Alzheimers Disease
In the new research, the team studied a rare form that has the name dominantly inherited Alzheimers disease , or autosomal dominant Alzheimers disease.
The data for the study came from the Dominantly Inherited Alzheimers Network , which is an international consortium that Washington University leads. The aim of the network is to investigate the causes of Alzheimers disease.
DIAD arises from a mutation in one or more of three genes: PSEN1, PSEN2, or APP.
People with DIAD typically experience memory loss and other symptoms of dementia in their 30s, 40s, and 50s.
The researchers chose to study people with DIAD because the earlier onset of the disease gives a longer timespan over which to investigate brain changes before cognitive symptoms emerge.
The analysis took in data on more than 400 people in the DIAN network. This number included 247 who were carriers of a genetic mutation and 162 of their blood relatives who were not carriers.
All the individuals had attended a DIAN clinic and given a blood sample, completed cognition tests of memory and thinking skills, and undergone brain scans. In addition, around half had made repeat clinic visits, with up to 3 years between each.
Those With Dementia Had Higher Levels Than Those That Did Not
For their research, the authors studied subjects from the King’s College London, Lund University and Alzheimer’s Disease Neuroimaging Initiative, including those with no symptoms. “This study shows that neurofilament light chain levels were particularly increased in adults with Down syndrome who have a genetic predisposition for Alzheimer’s disease,” said co-author Andre Strydom, Professor in Intellectual Disabilities at King’s College London. “Furthermore, we showed that those individuals with a dementia diagnosis following onset of Alzheimer’s disease had higher levels than those who did not. This suggests that the new marker could potentially be used to improve the diagnosis of Alzheimer’s in people with Down syndrome, as well as to be used as biomarker to show whether treatments are effective or not. It is exciting that all that could be needed is a simple blood test, which is better tolerated in Down syndrome individuals than brain scans.”
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Can You Detect Alzheimers With A Blood Test
A blood test was highly accurate in determining whether cognitive changes and memory loss were due to Alzheimers disease in 1,402 people, based on blood samples taken from a total of 1,402 people. Alzheimers disease was also accurately identified before it developed. It is still unclear whether the findings are true.
Blood Tests To Check For Other Conditions
Your GP will arrange for blood tests to help exclude other causes of symptoms that can be confused with dementia.
In most cases, these blood tests will check:
- liver function
- haemoglobin A1c
- vitamin B12 and folate levels
If your doctor thinks you may have an infection, they may also ask you to do a urine test or other investigations.
Read more about blood tests.
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Blood Test Is 94 Per Cent Accurate At Identifying Early Alzheimer’s Disease
Up to two decades before people develop the characteristic memory loss and confusion of Alzheimer’s disease, damaging clumps of protein start to build up in their brains.
Now, a blood test to detect such early brain changes has moved one step closer to clinical use.
Researchers from Washington University School of Medicine in St. Louis report that they can measure levels of the Alzheimer’s protein amyloid beta in the blood and use such levels to predict whether the protein has accumulated in the brain.
When blood amyloid levels are combined with two other major Alzheimer’s risk factors – age and the presence of the genetic variant APOE4 – people with early Alzheimer’s brain changes can be identified with 94 per cent accuracy, the study found.
The findings, published on 1 August in the journal Neurology, represent another step toward a blood test to identify people on track to develop Alzheimer’s before symptoms arise. Dr James Pickett, Head of Research at Alzheimers Society, said:
How The Sage Test For Dementia Works
SAGE stands for Self-Administered Gerocognitive Examination and was developed by researchers at The Ohio State University Wexner Medical Center.
The SAGE test has 12 questions that cover all aspects of cognition, including memory, problem solving, and language.
There are 4 different versions of the test. Theyre similar enough, but having multiple versions means that someone could take the test once a year and wouldnt improve their score each year just from the practice of taking it before.
This way, the test is slightly different each time.
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Are There Any Other Blood Tests For Alzheimers
There is another blood test for dementia that is showing great potential for diagnosing the progressive illness.
Simoa test
It is known as Simoa which stands for single-molecule array.
This is also designed to test if there are any proteins in the blood plasma. This test can detect a protein known as ptau181 which has been linked to some of the changes that dementia causes in the brain.
Various studies revealed that Simoa is as effective at predicting dementia development as a spinal tap and PET scans.
The Simoa blood test, however, ELIMINATES the pain, cost, and radioactivity that are associated with the other tests.
Simoa can also detect upcoming changes in the brain that are caused by dementia for both short and long-term i.e. 15 months and 4 years respectively.
At the moment, researchers are using this technology to identify ideal candidates for clinical trials because it is not yet available for many people with the illness.
Apart from Simoa, there are other types of blood tests that are still in development.
Other blood tests
Some are looking into fatty amides or protective fats in the blood.
Studies indicate that if there are increased levels of fatty amide in the blood, it may be an indication of the accumulation of beta-amyloid in the brain.
Researchers are also working on blood tests that will measure other proteins like the NfL and tau proteins.