Dementia And Memory Loss: How Is Alzheimer's Disease Diagnosed Definitively?

Despite significant advances in diagnostic tools, determining how Alzheimer’s disease is diagnosed definitively remains a central challenge in neurology and geriatric medicine. However, emerging technologies and methodologies—ranging from advanced imaging and blood tests to cognitive assessments—are improving the accuracy of diagnosing Alzheimer’s.

As detection methods become more refined, individuals affected by memory concerns and their families may be able to get earlier support, therapies, and clinical research opportunities. Here, we’ll examine how Alzheimer's is identified today, what these assessments involve, and how prevention and early intervention can contribute to mental health and well-being during the process. 

What is dementia? Understanding Alzheimer’s disease

Dementia is a general term for a decline in cognitive function, with Alzheimer's disease as its most common cause. The terms are often used interchangeably, though Alzheimer's represents a specific and progressive neurological condition.

Alzheimer's disease is a neurodegenerative disorder that gradually impairs memory, thinking skills, and, eventually, the ability to carry out simple tasks. This disease process typically unfolds over many years, making early detection both challenging and important.

Experts suggest that Alzheimer’s usually develops due to a combination of factors, such as:

• Advancing age
• Genetic predisposition
• Environmental influences
• Lifestyle choices
• Coexisting health concerns
  
  

Some risk factors, such as age or genetic inheritance, cannot be modified. However, adjusting factors such as high blood pressure, lack of physical activity, and smoking as much as possible may reduce one’s risk or slow progression. 

Signs and symptoms of Alzheimer’s and dementia

Signs of Alzheimer’s disease often begin with small shifts in behavior or cognition. Common symptoms include:

• Memory loss that disrupts daily life
• Difficulty planning or solving problems
• Confusion with time or place
• Challenges in understanding spatial relationships
• Trouble with vocabulary in speaking or writing
• Poor judgment and decision-making
• Withdrawal from social or work activities
• Mood and personality changes
  
  

These symptoms often develop gradually, which can make distinguishing normal aging from disease more nuanced.

How Alzheimer’s disease affects the brain

Alzheimer's disease impacts the brain and spinal cord. However, the most notable changes are typically rooted in the brain’s structure and function. Research suggests that over time, several interconnected processes contribute to the progression of symptoms, including:

• Disrupted neural communication: Brain cells have trouble sending signals, especially in areas that control memory and thinking.
• Neuronal loss and brain atrophy: Brain cells die over time, causing important areas like the hippocampus to shrink.
• Toxic protein buildup: Harmful proteins, like amyloid and tau proteins, build up and block normal cell function.
• Metabolic dysfunction: The brain has a harder time using energy, which can make it more difficult for brain cells to work properly.
• Inflammation and vascular damage: Ongoing swelling and poor blood flow in the brain can lead to more damage and faster memory loss.

What causes memory loss? 

Memory loss can arise from various health conditions, with not all of them linked to Alzheimer’s disease. It may also stem from vitamin deficiencies, thyroid imbalances, depression, certain medications, or trauma to the brain and spinal cord.

In the context of dementia, memory loss is more persistent and progressive. For individuals experiencing mild cognitive impairment (MCI), memory issues may be noticeable but not yet interfere significantly with daily life. However, MCI can sometimes (though not always) signal an early stage of Alzheimer’s.

Signs of memory loss

Because memory concerns may have many possible roots, identifying the cause isn't always straightforward. Still, certain indicators can raise red flags, especially in relation to Alzheimer’s, such as:

• Repeating the same questions or stories
• Getting lost in familiar places
• Misplacing items in illogical spots
• Struggling with word-finding
• Forgetting important dates or events
  
  

Recognizing these signs early allows for timely medical tests and discussions with healthcare providers.

How is Alzheimer’s disease diagnosed definitively? 

Exploring the diagnosis process: brain imaging, mental status, blood tests, and more

Although there is no definitive test to diagnose Alzheimer’s disease, several tools are now used to help make this diagnosis during life with increasing precision. The Alzheimer’s Association highlights a range of evaluations that, when combined, can offer a clearer view of the disease process and allow for earlier, more accurate diagnosis.

These diagnostic approaches typically include:

• A medical history review
• A physical exam and neurological exam
• Mental status testing
• Neuropsychological testing
• Brain imaging (magnetic resonance imaging (MRI))
• Laboratory tests
• Spinal fluid analysis
• Alzheimer’s-specific blood tests
• Genetic testing
• Brain imaging as part of the answer to “How is Alzheimer’s disease diagnosed definitively?”

Each brain imaging technique highlights different aspects of brain health. For example:

• Magnetic resonance imaging (MRI): shows detailed images of brain structure. Shrinkage in areas like the hippocampus can suggest Alzheimer’s.
• Positron emission tomography (PET): highlights metabolic activity and can reveal amyloid and tau proteins before symptoms are visible

Mental status exam

A mental status exam is a tool used to check how the brain is working, similar to how a physical exam looks at overall health. During the exam, a provider may ask questions and observe how someone speaks, behaves, and responds. It typically focuses on:

• Attention and focus
• Memory and recall
• Reasoning and problem-solving
• Language and communication
• Mood, behavior, and awareness of surroundings

Blood tests

Recent research suggests a promising new direction in detecting Alzheimer's, which involves blood-based testing. The PrecivityAD2 test has shown around 90% accuracy in identifying Alzheimer’s disease in older adults. This test detects amyloid and tau proteins, key biological markers of the condition. Unlike imaging or spinal fluid tests, it’s quick and less invasive, possibly making earlier diagnosis more widely available. In studies, it outperformed traditional clinical assessments, which were only 61–73% accurate. While it’s not yet FDA-approved yet and isn’t widely covered by insurance, further research in diverse populations is underway.

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Prevention and early intervention

While there is currently no guaranteed way to prevent Alzheimer’s disease, certain strategies may reduce one’s risk or slow progression, such as:

• Regular exercise: Movement can support cardiovascular and brain health.
• Heart-healthy eating patterns: Plans like DASH or the Mediterranean may help protect brain function. Speak to your doctor or a nutritionist before making major changes to your eating patterns.
• Managing conditions: Keeping blood pressure, cholesterol, and diabetes in check can be critical.
• Mental and social engagement: Life-long learning, puzzles, conversations, and hobbies may strengthen cognitive reserve.
• Injury prevention: Wearing a helmet during potentially dangerous activities and reducing fall risk can help avoid traumatic brain injury.
• Clinical trials: Some studies now focus on early treatment with antibodies to try and prevent or delay Alzheimer’s.

How therapy can help

Living with Alzheimer’s disease, or supporting someone who is, can involve a number of emotional and psychological challenges. Cognitive behavioral therapy (CBT) may assist patients in the early stages by helping them develop coping strategies and maintain a sense of purpose. For caregivers and family members, therapy can offer emotional support, stress relief, and tools to navigate the evolving caregiving role. 

The benefits of online therapy

While online therapy isn’t a way of treating Alzheimer’s disease, research suggests that it may often be effective for addressing related emotional and mental health difficulties, such as depression, anxiety, or caregiver stress—all of which can be part of the Alzheimer’s journey. Online therapy through a platform like BetterHelp involves getting matched and then meeting with a licensed therapist remotely, via phone, video, and/or in-app messaging. This format allows you to connect with your provider at times and from a place that is convenient for you. You can also switch therapists at any time for no additional cost.