Dementia Diagnostics – From Traditional to the Latest Advancements

Here are the typical first steps:

1. Clinical Examination: This is the initial step in diagnosing Alzheimer’s/dementia, which involves a comprehensive medical history and physical examination. This can help rule out other potential causes of symptoms, like medication side effects, depression, or other physical ailments. However, it’s limited because it can’t definitively diagnose Alzheimer’s or dementia; other tests are needed to confirm the diagnosis.
2. Neurological Examination: In a neurological exam, a physician assesses the patient’s physical and cognitive functioning, including reflexes, coordination, balance, and senses. This can help identify symptoms of brain disorders that could be causing cognitive impairment, but it doesn’t precisely diagnose Alzheimer’s/dementia.

Cognitive tests are essential tools in the diagnosis and tracking of dementia, including Alzheimer’s disease. They help assess a person’s cognitive abilities, such as memory, attention, language, and problem-solving skills. Here are some commonly used cognitive tests:

1. Mini-Mental State Examination (MMSE): This test assesses a range of cognitive abilities, including orientation to time and place, memory, attention, language, and visuospatial skills. The maximum score is 30, with lower scores indicating greater cognitive impairment.
2. Montreal Cognitive Assessment (MoCA): Similar to the MMSE, this test also examines a range of cognitive abilities. It is more sensitive to mild cognitive impairment (MCI) and early stages of dementia. It includes tasks like drawing a clock, repeating a list of words, and identifying animals in pictures. The maximum score is 30, with scores below 26 often considered indicative of cognitive impairment.
3. Clock Drawing Test (CDT): This is a simple and quick test where the person is asked to draw a clock and set a specific time. It is often used as a screening tool for cognitive impairment and dementia and can provide insight into a person’s visual, spatial, and executive functions.
4. Mini-Cog Test: This brief cognitive screening test combines a three-word recall test and the clock drawing test. It is useful for identifying individuals who might need a more thorough cognitive evaluation.
5. Addenbrooke’s Cognitive Examination (ACE): This is a more comprehensive cognitive test that includes the MMSE and also assesses other aspects of cognition, such as verbal fluency and memory recall.
6. Neuropsychological testing: This is a more comprehensive approach involving a battery of tests administered by a trained psychologist. It offers a more in-depth evaluation of various cognitive domains, including memory, attention, language, problem-solving, visuospatial abilities, and executive function.
7. SLUMS: The Saint Louis University Mental Status (SLUMS) Examination is a cognitive screening tool developed by researchers at Saint Louis University. This examination includes 11 tasks that evaluate a broad range of cognitive abilities.

These cognitive tests are vital tools for clinicians in diagnosing dementia and tracking the progression of the disease over time. However, no single test is definitively diagnostic for dementia, and these assessments are used in conjunction with a thorough medical history, physical examination, and appropriate imaging or laboratory tests. 

Here is the next level of tests that are typically performed.  

1. Lab Tests: Blood and other lab tests can help rule out other potential causes of symptoms, such as vitamin deficiencies or thyroid problems. However, they cannot diagnose Alzheimer’s/dementia.
2. Brain Imaging: Techniques like computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography (PET) can show structural and functional changes in the brain that might suggest Alzheimer’s disease. For instance, they can reveal brain shrinkage, stroke damage, or plaque deposits characteristic of Alzheimer’s. They are quite effective but don’t give a definitive diagnosis, as similar changes can be seen in other conditions.
3. Cerebrospinal Fluid (CSF) Tests: Certain proteins (e.g., beta-amyloid and tau) are elevated in the CSF of people with Alzheimer’s. However, a lumbar puncture (spinal tap) is needed to obtain CSF, which is an invasive procedure with potential side effects.
4. Genetic Testing: Rare cases of Alzheimer’s are caused by specific genetic mutations, and testing can confirm these. However, this is usually only done in cases of early-onset Alzheimer’s or if there’s a strong family history of the disease. This is quite accurate for these rare types but not applicable to most cases.
5. Biomarkers: This is a rapidly advancing field in Alzheimer’s research, with the aim to find measurable indicators of the disease process in the body, such as abnormal levels of certain proteins in blood or CSF. However, these are not yet used in routine clinical practice as of my knowledge cut-off in September 2021.

Each of these methods has limitations, and none can definitively diagnose Alzheimer’s/dementia on its own. Therefore, a combination of tests is typically used, and the diagnosis often involves a degree of clinical judgment. Even then, the accuracy can vary, with misdiagnosis rates reported to be as high as 20% in some studies. New diagnostic methods are being researched with the hope to improve accuracy and enable earlier diagnosis.

More recently, a variety of new diagnostics are in development or are already in practice leveraging the new capabilities enabled by Artificial Intelligence (AI).

1. AI techniques associated with MRI: According to a review article, AI techniques associated with MRI resulted in increased diagnostic accuracy ranging from 73.3% to 99%.
2. Extensive data sets: The application of AI-based techniques for Alzheimer’s disease (AD) and other diseases research requires extensive data sets, composed of hundreds to thousands of patients, to train and validate the algorithms.
3. Algorithm to identify individuals with cognitive impairment: Geisinger and Eisai plan to study the potential of artificial intelligence (AI) by testing the effectiveness of an algorithm to identify individuals with cognitive impairment who may develop dementia.
4. Computerized cognitive tests: Recently introduced AI-based tests include computerized cognitive tests, computer-assisted interpretation of brain scans, and movement – and speech analysis.

And most recently, there have been some new technologies, including AI-enabled tests, that can provide much earlier detection with a high degree of accuracy.  

1. Retinal biomarkers: Retinal biomarkers have been attracting intense interest in the detection and diagnosis of Alzheimer’s and other dementias. Hyperspectral retinal imaging (HSRI) is a promising new tool for diagnosing AD and other types of dementia. HSRI uses a camera to capture images of the retina at different wavelengths of light. These images can then be analyzed to detect changes in the retina that are associated with AD and other dementias. Early research suggests that HSRI may detect AD even in people in the early stages of the disease when there are no or few symptoms (read more here).
2. EEG and AI: Machine learning has been employed using hundreds of subjects with various types of dementia and differing levels of advancement. A battery of video images is presented, and the resulting brain activity is measured using electroencephalogram (EEG) methods.

AI is being employed in everything from diagnostics to the discovery of new drugs (read more here). Additionally, there have been more advancements in the treatment drugs and protocols, though there still is no cure (read more here).

All images and text © 2023 James M. Sims unless otherwise noted.