Alzheimer’s disease is an insidious brain disorder that progressively damages the brain, so it’s essential that it be diagnosed as early as possible. But how is Alzheimer’s diagnosed? Many people have heard of the most common symptoms of the disease, but they often don’t recognize them at its onset. Accurately diagnosing Alzheimer’s requires substantial medical attention, so it’s important to circulate detailed information on the diagnostic process.
Initial Assessment
For suspected Alzheimer’s disease, an initial assessment must be carried out to determine if an individual is suffering from the disorder and how advanced the symptoms are. An early Alzheimer’s test is carried out by a person’s primary care physician (PCP). During the first appointment, the PCP will begin by asking the patient about their symptoms and then thoroughly examine all the possibilities.
The PCP will gather the patient’s medical history to identify anything that may indicate early onset dementia, which may later become Alzheimer’s. They may also request family input to work out precisely how the individual’s behavior or personality has changed and to find out if there is a family history of Alzheimer’s. All of this information is pertinent and relevant when analyzing the existence and severity of symptoms. [1]
In some cases, the PCP may order blood or urine tests that may help to identify any other underlying medical issues, and they might also test things like sight and hearing. It’s important that they rule out any other possibilities in order to avoid a misdiagnosis. Still, if they strongly suspect Alzheimer’s disease, they will move on to organizing more cognitive tests. [1]
Cognitive and Neuropsychological Tests
There are several worrying cognitive signs that suggest an individual may be suffering from Alzheimer’s disease. These include:
- Memory problems.
- Sudden changes in personality.
- Spatial and vision issues.
- Poor attention span.
- Repeating questions or sentences.
- Getting lost in public.
- Taking longer to complete simple tasks. [2]
When an individual begins to exhibit these symptoms, it’s time to book an appointment with a PCP. They will carry out various different types of neuropsychological testing for Alzheimer’s, focusing on an individual’s cognitive behaviors and capabilities. These early tests usually determine whether or not medical professionals will conduct more thorough examinations for Alzheimer’s in the future.
Some of the most common and effective cognitive and behavioral tests include:
- The Mini-Cog – a three-minute memory test that also requires patients to accurately draw a clock. A healthcare professional will review the results and decide if an in-depth follow-up assessment will be needed.
- The General Practitioner Assessment of Cognition – a test that screens an individual for signs of cognitive impairment. The patient first takes Part 1 of the test, and if they fail, they must also complete Part 2.
- The Eight-item Informant Interview to Differentiate Aging and Dementia – a questionnaire-style interview used to gain more information and differentiate between normal signs of aging and signs of early dementia. [3]
Overall, what health providers want to test are the individual’s core cognitive abilities. They need to examine how well a patient can retain and recall information, whether they can logically solve problems, how they communicate, their attention to detail, and their level of comprehension.
Physical and Neurological Tests
Though Alzheimer’s is a brain disease, it’s also important to carry out physical and neurological tests to help rule out other potential conditions and analyze any physical symptoms that could impact an individual’s quality of life.
During a physical and neurological examination for an Alzheimer’s diagnosis, the PCP will usually consider factors like:
- The patient’s diet and alcohol consumption.
- Blood pressure and heart rate.
- The patient’s level of regular exercise.
- Testing blood and urine samples.
- Any medications the patient is taking.
- The patient’s usual quality of sleep. [4]
Testing and examining these things can help to distinguish actual signs of Alzheimer’s from other things that present similar symptoms. The patient could be suffering from a variety of different ailments, such as vitamin deficiency, sleep apnea, thyroid issues, side effects brought on by medications, and even depression. PCPs understand how to diagnose Alzheimer’s, so if they believe a patient has it, further assessments will be carried out. [4]
Brain Imaging Techniques
Beyond the routine psychological, physical, and neurological tests, how is Alzheimer’s diagnosed? If healthcare professionals suspect Alzheimer’s disease, they will propose brain imaging tests to analyze and monitor how the disorder is changing an individual’s brain. As the disease is progressive, it is essential to manage its development and note where most of the damage is occurring. [5]
There are three primary brain imaging techniques involved in early Alzheimer’s testing:
- Computed Tomography (CT) – X-ray images of the brain’s structure to help identify causes of cognitive decline and any signs of shrinkage, fluid, or blood.
- Magnetic Resonance Imaging (MRI) – more detailed images of the brain, providing insight into structural and vascular damage.
- Positron Emission Tomography (PET) – 3D images of the brain highlighting its structural metabolism, with radioactive technology to trace disease and injury. [5]
With the images provided by technologies like CT, MRI, and PET scans, medical professionals can make more informed judgments about how to diagnose Alzheimer’s in a patient, what stage the disease is currently at, and what treatment therapies to use. [5]
Laboratory Tests and Biomarkers
After all the initial assessments, the tests for an Alzheimer’s diagnosis become more extensive, but this is necessary for accurately examining and monitoring a patient’s symptoms. Medical professionals may carry out blood tests to check for signifiers of Alzheimer’s disease, though the diagnosis can usually be confirmed via a brain scan.
Researchers have been working to develop the blood tests involved in diagnosing Alzheimer’s, particularly the examination of biomarkers of the disease. They typically test a patient’s blood for proteins called amyloid beta and tau, which relate to Alzheimer’s. A significant build-up of these proteins can cause them to move from the brain to the bloodstream, making them easier to identify. More specific emerging biomarker tests show promising results and may help revolutionize the future of Alzheimer’s testing and care. [6]
Genetic Testing for Alzheimer’s
Genetic testing is used to successfully anticipate and diagnose several different types of diseases, but it isn’t one of the most common processes in Alzheimer’s assessments. This is because there are currently no reliable genetic tests available for those suffering from Alzheimer’s disease, so it’s not even a feasible option for family members who have relatives with the disorder, which could be genetically transmitted.
Neurologists may be able to use genetic testing to identify patients who have an increased risk of developing Alzheimer’s in the future, but they cannot accurately determine who will or won’t actually develop it. Despite its current limitations, more research is being done into the potential of genetic testing for Alzheimer’s as it may make it easier to identify brain changes before symptoms of the disease progress. Anything that may benefit the neurological and psychological study of Alzheimer’s will be pursued. [2]
Differential Diagnosis
The symptoms of suspected Alzheimer’s disease are well-known, but they are also often very similar to signs of different disorders and ailments that also impact the brain. That’s why so much invasive and extensive testing is required to differentiate between symptoms and ensure an accurate Alzheimer’s diagnosis.
Memory problems, for instance, are very common among individuals who have suffered brain traumas like a stroke or the development of a tumor. Brain scans and blood tests can be used to differentiate these symptoms from those of Alzheimer’s. People who have Parkinson’s disease also suffer similar cognitive problems to those with Alzheimer’s, particularly memory loss, confused thinking, and difficulty performing certain everyday tasks. Distinguishing between the two is integral for appropriate patient care. [1]
Sometimes, a patient may be experiencing an infection or deficiency that mimics the signs of Alzheimer’s disease. Even if these symptoms seem mild, it’s important to test them just in case they are caused by Alzheimer’s. And Alzheimer’s isn’t the only type of dementia. There are others, such as Vascular dementia and Lewy Body dementia, that cause an individual to experience similar early symptoms. A PCP will be able to recommend the appropriate tests to form a differential diagnosis. [1]
Challenges in Early Diagnosis of Alzheimer’s
Plenty of in-depth research and testing has been and continues to be done to better analyze Alzheimer’s and how it develops. There is currently no cure for Alzheimer’s disease, though there are medications available to help manage the symptoms, so this ongoing work is as important as ever.
However, there are a few challenges facing the early detection and diagnosis of Alzheimer’s. Biomarker tests, for example, would be incredibly useful for observing subtle brain changes that may not become obvious through other imaging techniques until the disease has progressed beyond the initial stages. Being able to accurately identify early-onset Alzheimer’s disease would also offer people more information on signs to look out for and help them better prepare themselves if they’re at risk. [8]
Researchers are working to improve early detection in order to fight the insidious nature of the disorder, which often comes out of nowhere and takes people by surprise. Receiving an Alzheimer’s diagnosis is jarring and changes the rest of an individual’s life.
With fewer challenges in the initial detection stage, healthcare providers would have more specific technologies to help them scan brains and test blood to accurately determine the existence of Alzheimer’s without the need for such extensive patient testing. But until this ongoing research is perfected, it’s important for people to seek medical advice as soon as they notice symptoms. [8]
- National Institute on Aging. (2022, December 8). How is Alzheimer’s disease diagnosed? National Institute on Aging. https://www.nia.nih.gov/health/alzheimers-symptoms-and-diagnosis/how-alzheimers-disease-diagnosed
- National Institute on Aging. (2023). Alzheimer’s disease fact sheet. National Institute on Aging; National Institutes of Health. https://www.nia.nih.gov/health/alzheimers-and-dementia/alzheimers-disease-fact-sheet
- Alzheimer’s Association. (2022). Cognitive Assessment. Alzheimer’s Disease and Dementia. https://www.alz.org/professionals/health-systems-medical-professionals/cognitive-assessment
- Alzheimer’s Association. (2024). Medical Tests for Diagnosing Alzheimer’s. Alzheimer’s Disease and Dementia; Alzheimer’s Association. https://www.alz.org/alzheimers-dementia/diagnosis/medical_tests
- Johnson, K. A., Fox, N. C., Sperling, R. A., & Klunk, W. E. (2012). Brain Imaging in Alzheimer Disease. Cold Spring Harbor Perspectives in Medicine, 2(4), a006213–a006213. https://perspectivesinmedicine.cshlp.org/content/2/4/a006213
- Reynolds, S. (2024, August 13). Accurate blood test for Alzheimer’s disease. National Institutes of Health (NIH). https://www.nih.gov/news-events/nih-research-matters/accurate-blood-test-alzheimer-s-disease
- Mistur, R., Mosconi, L., Santi, S. D., Guzman, M., Li, Y., Tsui, W., & de Leon, M. J. (2009). Current Challenges for the Early Detection of Alzheimer’s Disease: Brain Imaging and CSF Studies. Journal of Clinical Neurology (Seoul, Korea), 5(4), 153–166. https://www.thejcn.com/DOIx.php?id=10.3988/jcn.2009.5.4.153
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MentalHealth.com is a health technology company guiding people towards self-understanding and connection. The platform provides reliable resources, accessible services, and nurturing communities. Its purpose is to educate, support, and empower people in their pursuit of well-being.
Michael Quinn is a writer with five years of experience unpacking everything from technology and politics to medicine and telecommunications.
Morgan Blair is a licensed therapist, writer and medical reviewer, holding a master’s degree in clinical mental health counseling from Northwestern University.
Further Reading
Our Medical Affairs Team is a dedicated group of medical professionals with diverse and extensive clinical experience who actively contribute to the development of our content, products, and services. They meticulously evaluate and review all medical content before publication to ensure it is medically accurate and aligned with current discussions and research developments in mental health. For more information, visit our Editorial Policy.
MentalHealth.com is a health technology company guiding people towards self-understanding and connection. The platform provides reliable resources, accessible services, and nurturing communities. Its purpose is to educate, support, and empower people in their pursuit of well-being.