Assessment For Alzheimer’s Disease

By Alan B

October 16, 2022

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If You Are Diagnosed With Dementia

Neuropsychological Assessment of Alzheimer’s Disease

Obtaining an early and accurate diagnosis can improve the quality of life for people with dementia.

Talk to your doctor about treatment and ongoing assessment.

Support and information is available through the National Dementia Helpline on 1800 100 500.

Thanks to Associate Professor David Ames for reviewing this material.

What Does Sage Stand For

The Self-Administered Gerocognitive Exam, known as SAGE, is a brief, pen-and-paper cognitive assessment tool designed to detect the early signs of cognitive, memory, or thinking impairments. The test evaluates your thinking abilities. This can help your doctors understand how well your brain is functioning.

Douglas Scharre, MD, director of the division of cognitive neurology at The Ohio State University Wexner Medical Center in Columbus, developed the test over a five-year period based on clinical experience and review of literature.

Questions were designed to evaluate every part of a patients brain,” Dr. Scharre explains.

The scoring for SAGE was designed to give equal weight for questions that assess brain function for the front, the back, the left, and the right side of the brain, so that no area was overrepresented.

SAGE will not diagnose any specific condition. It will not tell your doctor if you have Alzheimers disease or any other condition that can impact your thinking.

But it is a helpful screening tool for mild cognitive impairment from any cause and early dementia.

The Functional Independence Measure

The Functional Independence Measure measures overall disability. It is observer rated and covers multiple important domains, including self-care, sphincters, mobility, communication, psychosocial function and cognition. Some training is required for its use. A UK version is available and it has been used in repeated observations of inpatients in general hospital . It is therefore an example of a scale which addresses cognitive as well as physical function, and is likely to be especially useful in inpatient or rehabilitation settings.

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Computed Tomography And Magnetic Resonance Imaging

Structural imaging such as Computed Tomography or Magnetic Resonance Imaging yields a picture of the brain that allows identification of such features as volume loss or abnormal structural features such as white matter disease, masses, or vascular abnormalities, which are considered indications of neuronal degeneration. Newer techniques such as diffusion tensor imaging reveal subtle structural changes that may precede more easily identifiable volume loss in the brain. Functional imaging such as fMRI can be used to identify abnormal patterns of brain activation or metabolic activity.

Evaluation Of Mri Harmonization

We further assessed our image harmonization pipeline by clustering the data using the t-distributed stochastic neighbor embedding algorithm. We performed this procedure in order to ensure that input data for all models was free of site-, scanner-, and cohort-specific biases and such biases could not be learned by a predictive model. To accomplish , we performed tSNE using pixel values from post-processed, 8x-downsampled MRI scans. For , we performed tSNE using hidden-layer activations derived from the penultimate layer of a convolutional neural network developed for our prediction tasks . For the NACC dataset, we assessed clustering of downsampled MRIs and hidden layer activations based on specific Alzheimers Disease Research Centers and scanner manufacturers . We also repeated tSNE analysis based on specific cohorts using all available MRIs across our datasets. We also calculated mutual information scores between ADRC ID, scanner brand, and diagnostic labels in the NACC dataset. This metric calculates the degree of similarity between two sets of labels on a common set of data. As with the tSNE analysis, the MIS calculation helped us to exclude the presence of confounding site- and scanner-specific biases on MRI data.

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The Hamilton Depression Rating Scale

The Hamilton Depression Rating Scale is one of the most commonly used depression rating scales. It requires 2030 min of questions in a semi-structured interview by a trained interviewer, and is therefore unlikely to be used in people with dementia. It is commonly used in antidepressant drug trials, and like MADRS, has a preponderance of psychological rather than physical items.

Overview Of The Prediction Framework

We developed predictive models to meet two main objectives. The first, which we designated the COG task, was to predict the overall degree of cognitive impairment in each participant based on neuroimaging. To meet this goal, we predicted a continuous 02 score , which we denote as the DEmentia MOdel score. Of note, the COG task may also be regarded as consisting of three separate subtasks: separation of NC from MCI and DE , separation of MCI from NC and DE , and separation of DE from NC and MCI . The second objective, which we designated the ADD task, was to predict whether a participant held a diagnosis of AD or nADD given that they were already predicted as DE in the COG task. For ease of reference, we denoted the probability of a person holding an AD diagnosis as the ALZheimer score. Following the sequential completion of the COG and ADD tasks, we were able to successfully separate AD participants from NC, MCI, and nADD subjects.

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Who Should Consider Taking The Sage Test

According to Scharre, anyone who is experiencing memory, language, problem-solving, or thinking problems should consider taking SAGE.

This may be especially important if you are noticing very mild symptoms, since SAGE is designed to pick up early deficits and allow your healthcare providers to diagnose and manage any potential conditions at an early stage,” he explains.

Friends or family members may want to encourage a loved to take the test if they notice issues related to memory or thinking.

You may also wish to take a SAGE to establish a baseline cognitive assessment to use for comparison in the future if you have a family history of dementia or thinking problems.

Typically, we would suggest repeating the test every six months unless significant cognitive changes are occurring,” advises Scharre.

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You can download the test for free at the Wexner Medical Center website.

Theres also a digital version made for tablets produced by a company called BrainTest. It consists of identical test questions. This version is scored by a panel and results are sent to you so can take them to your primary care physician for further discussion. You can download the electronic version at BrainTest.com.

How Accurate And Reliable Are The Results

Ulbl J: The Alzheimers Disease Assessment ScaleCognitive Subscale (ADAS-Cog): standardisation …

Like any test, SAGE is not perfect. Scharre points out that individuals have a wide variety of cognitive talents and this needs to be taken into account. There will be individuals who score well but have a decline from their previous abilities. Repeat testing over time will find those that are progressing, he explains.

Some individuals will not score as well, but that may represent their baseline talents, and their score would not suggest any specific brain condition,” he adds. This is why its important to have the test interpreted in light of ones medical history by a healthcare provider.

Its important to note that other factors could be affecting your memory and thinking on any given day.

Perhaps you dont have a memory impairment but are quite depressed, ill, or sleep deprived. explains Jessica Z. K. Caldwell, PhD, director of neuropsychology training and staff neuropsychologist at Cleveland Clinics Ruvo Center for Brain Health in Las Vegas, Nevada. If you have concerns about your memory but are also experiencing these symptoms, Dr. Caldwell suggests you see your doctor.

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The Geriatric Depression Scale

The Geriatric Depression Scale is the most commonly used assessment of depressed mood among older people, and has been shortened to numerous versions, including a popular 15-item version . GDS-15 is usually self rated though can be rated by an assessor. It is sensitive to change and is reliable in older people in institutional care. It takes about 510 min to administer. Its major drawback in dementia is that it has been validated for people with mild dementia, but not for those with moderate to severe dementia .

Medical History And Mental Status Examination

Clinical assessment of a patients history and performing a mental status examination are necessary steps in the evaluation of cognitive disorders. In identifying the presence of AD, the presence of a typical slow and insidious progression of symptoms is sought. Other factors capable of producing cognitive impairment are identified, including medical disorders, substances or medications that can cause cognitive impairment, or psychiatric conditions associated with cognitive changes. The characteristic clinical syndrome of AD includes a prominent disturbance of what is known as episodic memory .

Memory of recent events is particularly impaired, and evidence that reminders are of limited benefit is consistent with the memory storage problem typically found in AD. Language and visuospatial problems may also be reported or identified. In less common variants of AD, the disturbance of language or visual functions may be more prominent than memory difficulties in the diseases early stage.

What Evidence Is There That These Tests Accurately Assess Alzheimers Disease And Mci

Alzheimers patients performed significantly worse than healthy volunteers on all of the critical tests of the battery . Similar, though less severe deficits were found in MCI patients on all of these tests except RTI. Furthermore, scores on Cantab tests are associated with the clinical progression of the disease, as assessed by measures of global impairment, such as the MMSE and to functional impairment of key brain areas affected in MCI and dementia .

One of the key challenges in dementia research is predicting progression to Alzheimers Disease in patients with MCI. Over a year, approximately 5% of cases of MCI go on to be diagnosed with Alzheimers Disease . Fowler et al. found that deteriorating performance on PAL was able to predict this progression, consistent with the finding that MCI patients with an episodic memory deficit are at higher risk of developing AD .

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Mri Harmonization And Preprocessing

To harmonize neuroimaging data between cohorts, we developed a pipeline of preprocessing operations that was applied in identical fashion to all MRIs used in our study. This pipeline broadly consisted of two phases of registration to a standard MNI-152 template. We describe Phase 1 as follows:

Scan axes were reconfigured to match the standard orientation of MNI-152 space.
Using an automated thresholding technique, a 3D volume-of-interest within the original MRI was identified containing only areas with brain tissue.
The volume-of-interest was skull-stripped to isolate brain pixels.
A preliminary linear registration of the skull-stripped brain to a standard MNI-152 template was performed. This step approximated a linear transformation matrix from the original MRI space to the MNI-152 space.

Phase 2 was designed to fine-tune the quality of linear registration and parcellate the brain into discrete regions. These goals were accomplished by the following steps:

All steps of our MRI-processing pipeline were conducted using FMRIB Software Library v6.0 . The overall preprocessing workflow was inspired by the harmonization protocols of the UK Biobank . We manually inspected the outcome of the MRI pipeline on each scan to filter out cases with poor quality or significant processing artifacts.

How Is Alzheimer’s Disease Diagnosed

Doctors use several methods and tools to help determine if a person with thinking or memory problems has Alzheimers disease. To diagnose Alzheimers, doctors may:

Ask the person experiencing symptoms, as well as a family member or friend, questions about overall health, use of prescription and over-the-counter medicines, diet, past medical problems, ability to carry out daily activities, and changes in behavior and personality.
Administer a psychiatric evaluation to determine if depression or another mental health condition is causing or contributing to a person’s symptoms.
Conduct tests of memory, problem solving, attention, counting, and language.
Order blood, urine, and other standard medical tests that can help identify other possible causes of the problem.
Perform brain scans, such as computed tomography , magnetic resonance imaging , or positron emission tomography , to support an Alzheimers diagnosis or rule out other possible causes for symptoms.

Doctors may want to repeat these tests to help best determine how the persons memory and other cognitive functions are changing over time. The tests can also help diagnose other causes of memory problems, such as stroke, tumor, Parkinsons disease, sleep disturbances, side effects of medication, an infection, or another type of dementia. Some of these conditions may be treatable and possibly reversible.

People with memory problems should return to the doctor every six to 12 months.

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Behavioral Variant Frontotemporal Dementia

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The behavioral variant of FTD usually begins insidiously with personality and behavioral changes such as inappropriate social conduct, inertia and apathy, disinhibition, perseverative behavior, loss of insight, hyperorality, and decreased speech output . These changes are followed by cognitive deficits which include alterations in judgment, problem solving, concept formation, and executive functions, often with relative sparing of visuospatial abilities and episodic memory. BvFTD and probable AD can be difficult to distinguish during life because of overlap in symptoms, but it has been suggested that AD is more often associated with constructional deficits than bvFTD. Although recent attempts to differentiate bvFTD and AD on the basis of the nature and severity of behavioral symptoms has met with some success , behavior-based methods are only partially effective and might be improved by considering other aspects of the disorders. This has led some researchers to investigate the possibility that differences in the patterns of cognitive deficits associated with bvFTD and AD might aid in differential diagnosis . Revised criteria for the clinical diagnosis of bvFTD have recently been validated against pathologically verified FLTD , which may improve diagnostic accuracy.

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Take The Sage Test At Home

Anyone can take the SAGE test anytime. Its free and you can get it here on the Ohio State University website.

Print the test and take it with a pen or pencil. Theres no time limit, but most people finish in about 15 minutes.

Sample questions from the test:

How many nickels are in 60 cents?
You are buying $13.45 of groceries. How much change would you receive back from a $20 bill?
Write down the names of 12 different animals.
Draw a large face of a clock and place in the numbers.Position the hands for 10 minutes after 11 oclock. On your clock, label L for the long hand and S for the short hand.

Language And Semantic Knowledge

Mildly demented patients with AD are often impaired on tests of object naming , verbal fluency , and semantic categorization . The underlying nature of these deficits has been debated but there is evidence that they reflect deterioration in the structure and content of semantic memory that supports language. Knowledge for particular items or concepts and the associations between them may be disrupted as the neuropathology of AD encroaches upon the temporal, frontal, and parietal association cortices in which they are thought to be diffusely stored .

Evidence for a deterioration of semantic memory in AD comes from several studies that probed for knowledge of particular concepts across different modes of access and output . These studies assume that loss of knowledge, as opposed to impaired retrieval of intact knowledge, would lead to consistency of performance across items . For example, if a patient has lost the concept of horse, they should not be able to name a picture of a horse, generate horse on a verbal fluency test, sort horse into its proper category as a domestic animal, and so on. The results of these studies showed that patients with AD were significantly impaired on all measures of semantic memory and, when a particular stimulus item was missed in one task, it was likely to be missed in other tasks that accessed the same information in a different way.

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Executive Functions Working Memory And Attention

The deficit in mental manipulation exhibited by patients with AD may also be expressed on tests of working memory. Working memory refers to a processing system whereby information that is the immediate focus of attention is temporarily held in a limited-capacity, language- or visually-based, immediate memory buffer while being manipulated by a central executive . Studies indicate that the working memory deficit of patients with AD is initially mild and primarily involves disruption of the central executive with relative sparing of immediate memory . It is not until later stages of AD that all aspects of the working memory system become compromised . Consistent with this model, mildly demented AD patients are often impaired on complex attention tasks that are dependent upon the effective allocation of attentional resources or that require efficient disengagement and shifting of attention . In contrast, the ability to focus and sustain attention is usually only affected in later stages of the disease. This is apparent in the essentially normal performance of mildly demented AD patients on tests of immediate attention span compared with supraspan tests .

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