It is important to understand the crucial role of cognitive reserve in dementia and how it affects diagnosis.
What is Cognitive Reserve?
Many studies are ongoing to determine what risk factors predict development of dementia, as well as to foresee who will more rapidly progress from mild cognitive impairment to dementia.
Cognitive reserve (CR) is a new area of interest in predicting how quickly dementia may worsen.
It is defined as a coping strategy against brain damage. This is the ability to use different brain networks to cope against loss of performance.
One way to think of CR practically is the brain’s capacity to improvise and find other ways of getting the job done to overcome obstacles and challenges.
CR was first thought of in the 1980s, when researchers found brain changes on autopsy consistent with advanced Alzheimer’s disease in people who had no symptoms when they were alive.
This meant these patients continued to function as usual, despite brain damage from Alzheimer’s pathology. This triggered a wide interest in research on whether people with a greater cognitive reserve can cope with brain changes of dementia (or even other disorders such as multiple sclerosis, Parkinson’s disease, or stroke).
“CR protects a person from clinical dementia”
The theory is, the higher a person’s CR, the more protected he or she would be against clinical dementia and loss of functioning.
Studies have tried to link dementia level to variables such as education, literacy, IQ, and engagement in cognitive exercises.
CR is the latest such variable to be added to the list of variables that can influence the development of dementia.
Genetics and exposure to environments (education, cognitively stimulating activities, and occupation) help develop CR.
There are some emerging predictive factors for converting from mild cognitive impairment to dementia.
Higher risk has been found for lack of occupation in the elderly, low formal education level, and difficulty coping with common situations.
Higher CR may be linked to decreased risk for dementia
Although larger studies are needed, a major research study published in JAMA neurology in 2019 of over 1600 patients in the Rush University Memory and Aging Project showed that those who scored in the highest cognitive reserve category had a reduced risk for dementia, even if they had high amounts of Alzheimer’s brain pathology at autopsy.
This strongly suggests that increased CR could reduce dementia risk.
How does one increase Cognitive Reserve?
Researchers propose that being exposed to an enriched environment, meaning high opportunities to participate in physical activity, ongoing learning, and keeping up social interactions may produce structural (and functional) changes in the brain.
Specifically, the hippocampus is important for memory and becomes impaired in Alzheimer’s disease, may be altered with practicing the above tasks.
Some have theorized learning a second language or doing Sudoku-type puzzles may “train” the brain’s CR, however, this has not yet been scientifically proven to delay or prevent Alzheimer’s disease.
How is Cognitive Reserve measured?
CR can be measured clinically by your doctor; in general, a person’s education level, work activities and activities performed in leisure can help gauge an estimate of CR.
There also exists a Cognitive Reserve Index questionnaire (CRIq) which formally assesses years of education, vocational training, type of occupation (ranging from unskilled to highly intellectual occupation), leisurely activities (reading newspapers, domestic chores, driving, sports, games, and using new technologies), and social activities.
Results are scored and then interpreted as low, medium-low, medium, medium-high, or high cognitive reserve.
It is important to note that these cutoffs have not yet been proven to predict a clinical outcome, but could be a useful tool and certainly an important research tool.
Why is Cognitive Reserve important?
CR may be very important in compensating for progressive brain damage in dementia. Although it doesn’t prevent dementia, high CR could mask the development of symptoms until a certain threshold.
For example, a person with a high CR can go undiagnosed until the damage becomes severe, whereas a person with a low CR may decompensate clinically much sooner.
What, besides increasing cognitive reserve, can be done to reduce the risk of dementia?
Studies show eating a healthy, plant-based diet with fruit, vegetables and legumes may be protective. Regular exercise including cardiac fitness, getting enough high-quality sleep, stress management, and nurturing social connections are all good practices to prevent cognitive issues later in life.
Continuing to challenge the brain with learning new material may be helpful as well.
There are a variety of ways doctors can test cognitive function in a person with dementia.
Often, a patient or a family member has picked up on clues that there is a problem with cognition.
However, are there ways to formally and objectively assess this?
The answer is, yes; there are a host of cognitive tests for dementia that range from simple bedside tests that take a few minutes to perform to in-depth neuropsychiatric testing that can take a few hours.
While imaging of the brain (MRI, CT, PET) can provide insights into brain structure and some types of brain imaging can even show metabolic and blood flow function, cognitive tests directly observe performance in certain domains and remain essential in the diagnosis of dementia.
In this article, we will describe what these tests are and how they affect the diagnosis and testing for dementia.
What Type of Doctor does Tests for Dementia?
These tests can be done by a primary care doctor or internist; often times they are also done by neurologists and psychologists.
Sometimes they are done to diagnose dementia; they can also be used to track dementia over time.
Types of Tests for Dementia
The first type of tests are called mental status scales.
These are short (<15 minutes) bedside tests administered by the doctor that assess memory and other cognitive domains.
They provide a score, which is used to distinguish people with normal vs. impaired cognition and even screen for mild cognitive impairment (MCI).
Examples of the most widely used include the Montreal Cognitive Assessment (MoCA) and the Mini-Mental State Examination (MMSE).
These are screening tests, meaning they are not diagnostic of any particular dementia or diagnosis, but when abnormal definitely can hint that cognition is impaired.
Moreover, these tests can be repeated over time to track the progression of the disease as well.
These tests assess memory, language, executive function, visuospatial skills, and attention/concentration.
The MMSE is scored on a 30 point scale. Specific items include orientation (10 points), memory (6 points), attention/concentration (5 points), language (8 points), and visuospatial function (1 point). A score of <23 is abnormal and indicates cognitive impairment.
It assesses delayed word recall/memory (5 points), visuospatial function (7 points, includes clock-drawing), language (6 points), attention/concentration (6 points), and orientation (6 points). A score of <25 is abnormal and indicates significant cognitive impairment.
Another similar test is the Saint Louis University Mental Status Examination (SLUMS) which is scored similarly.
All three of these tests are widely available and free to use.
Alternative shorter tests
There are several shorter tests (<5 minutes) that are frequently used in busy primary care settings as a screener for cognitive impairment.
A famous one is the clock drawing test (CDT) where the patient is asked to draw a clock and set the hands to a specific time.
This quickly and efficiently tests visuospatial abilities, executive function, motor execution, attention, language comprehension and numerical knowledge.
The CDT is interpreted as normal or abnormal.
Another popular test is the Mini-Cog, which includes remembering three unrelated words told to the patient in addition to the clock drawing test.
There are more in-depth cognitive tests that take longer (>15 minutes) and these include the Consortium to Establish a Registry for Alzheimer’s Disease Neuropsychological Battery (CERAD-NP).
This takes about 30 minutes to administer, and can specifically identify cognitive deficits characteristic of mild Alzheimer’s dementia.
Another test, called the Addenbrooke’s Cognitive Examination (ACE), is also specifically designed for Alzheimer’s dementia and tracking progress.
Lastly, there is formal neuropsychological or neuropsychiatric testing which is very in-depth and is useful in patients who meet criteria for mild cognitive impairment (MCI) or patients who score normally on the basic screening tests above but still have subtle or persistent cognitive symptoms.
This is not useful in advanced dementia.
After all, the testing requires the patient to be able to participate in complex tasks and questioning.
Neuropsychological testing can take up to six hours to complete and is not always required as part of a dementia evaluation.
It can be useful when tracking mild cognitive impairment over time to see if a patient is worsening or improving, before actually reaching the cognitive impairment threshold for dementia.
For the most part, the short tests are easy to access and are available online both to the general public and to doctors.
Most primary doctors are familiar with the MMSE and MOCA and may even perform them in their daily practice.
The formal, longer tests such as formal neuropsychological testing require a referral from your doctor to a center that performs such tests.
After these examinations, the doctor performing the tests will be able to interpret the results and categorize them into either “normal” or “abnormal” results.
Within “abnormal” results the doctor can distinguish whether dementia is mild, moderate, or severe. With certain tests, the different subtypes of dementia can be discovered as well (Alzheimer’s vs other types).
In conclusion, there are many facets towards a diagnosis of dementia; aside from history taking, physical examination, and brain imaging, there are a host of cognitive tests for dementia that are described above.
These range from short tests that only take a few minutes, to longer tests that can take up to several hours.
Each kind of test has a different purpose. It’s doctors (specifically neurologists) that may refer to different cognitive tests to evaluate for dementia.
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The common question that arises amongst the general public is whether or not do neurologists treat dementia.
While there are various specialists who can diagnose dementia, many patients are referred to a neurologist who determines the type of dementia, as well as treatment options.
What is dementia?
Dementia is a neurologic disease affecting cognition, involving the different aspects of cognitive function (memory, language, attention, social life, planning, and motor skills).
Dementia represents a decline that is severe enough to interfere with daily life and independence. When people think of dementia, Alzheimer’s comes to mind, and that’s because Alzheimer’s Disease is the most common type of dementia.
Alzheimer’s is responsible for about 60-80% of all dementias in older adults. With an aging population, the overall prevalence of dementia is increasing worldwide.
Dementia is a progressive disease, meaning it gets worse over time. In the early stages, it may be diagnosed at mild cognitive impairment (MCI), which is an in-between stage between normal cognition and dementia.
MCI may progress to dementia.
What are different kinds of dementia?
The most common dementia in older adults is Alzheimer’s Disease. However, about 20% of patients with dementia have another form of dementia.
While it does not have to be a neurologist to diagnose dementia, many patients are referred to a neurologist to determine what type of dementia they have and to help with treatment options and symptom management.
A primary care physician can make a presumptive diagnosis of dementia if a patient fits certain criteria, and the symptoms are not explained by another mental disorder (such as major depressive disorder or another psychiatric condition).
A neurologist can help distinguish between the different types of dementia.
In some cases, advanced neuropsychiatric testing is done to better clarify the type of dementia.
How is dementia diagnosed?
A full dementia evaluation cannot be done in a quick office visit; a family member or a close friend should accompany the patient to their primary physician or neurologist and be able to recount the history over the past several weeks, months, and even years.
The first steps include a complete history and physical examination, neurologic examination, and laboratory or imaging workup.
The history, or story of the patient’s symptoms, is crucial to the diagnosis.
A doctor might ask when the patient first noticed memory loss, how it has progressed, and what sorts of things he or she is not able to do anymore independently (activities of daily living, or ADLs).
There are several tests available to help with the diagnosis of dementia, which will be discussed further below.
A full evaluation includes a physical and neurologic exam, laboratory testing, and most times imaging tests such as a CT scan or an MRI of the brain.
By official definition, dementia is diagnosed when there is cognitive impairment in at least one cognitive domain (memory, language, attention, executive function, motor function, social function) that is progressive and interferes with independence in every-day activities, that is not explained by another medical or psychiatric disorder.
Why refer to a neurologist for dementia?
A neurologist will be helpful in diagnosing dementia, especially in distinguishing between different types of dementia as their treatments differ.
Also, a neurologist will perform a careful history and exam including labs and imaging to make sure there is nothing else being missed that would otherwise explain the symptoms of dementia.
In addition, a neurologist trained in cognitive neurology will have special expertise on managing the symptoms of dementia including the newest medications, clinical trials, and symptom management.
Often times, a neurologist will be able to give a prognosis and help guide family members through this chronic, progressive illness.
What does a neurologist examine for a dementia patient?
After taking a careful history of the symptoms, a neurologist will begin with a general physical examination.
Part of this includes the neurologic exam.
A neurologic exam contains six major components; mental status exam, cranial nerve exam, motor exam, sensory exam, reflexes, and cerebellar exam.
Abnormalities on the neurologic exam may give the neurologist clues as to what the diagnosis is.
The mental status exam will assess for orientation, attention, memory, visuospatial function, and language. Some common tools are the MOCA (Montreal Cognitive Assessment) and MMSE (Mini-Mental State Examination).
These are a short series of tasks a neurologist may ask you to fill out, and based on how you score, can help in categorizing the types of deficits and hint as to the type of dementia.
What treatments might a neurologist prescribe for dementia?
There are a few medications that are approved for the treatment of Alzheimer Disease. These include cholinesterase inhibitors (such as donepezil, rivastigmine, and galantamine).
These medications work by modulating neurotransmitters in the brain and have some modest symptomatic benefit in patients with dementia.
Another category of medication includes Memantine, which is an NMDA-receptor antagonist. This works by blocking a different neurotransmitter (NMDA) which may protect the brain.
This also has been shown to have very modest benefits.
Neurologists may prescribe medications to help certain symptoms of dementia, such as behavioral disturbances, hallucinations, sleep problems, depression, agitation, and aggression.
These may include antidepressants, antipsychotics and various other medications.
Nutrition, physical therapy and cognitive rehab are also things a neurologist may consider in the multidisciplinary approach to dementia care.
What conditions can be mistaken for dementia?
There are certain conditions that can mimic dementia. It is essential to make sure these conditions are not responsible for the symptoms, as they are often reversible and treatable.
A good neurologist will rule out “reversible” causes and mimics of dementia.
There are certain “red flags” that should not be missed; these include young age, rapidly progressive dementia (ie someone getting much worse within days, weeks or a few months), or an abnormal or asymmetric neurologic exam such as weakness on one side of the body.
These will need an expedited and different type of evaluation than the standard dementia workup.
Many people confuse the signs of normal aging with dementia.
Normal aging does include a slight degree of cognitive decline including mild changes in memory and information processing. Some people visit their doctor for these symptoms, worried that they may have dementia.
Normal aging is quickly recognizable from dementia
However, normal aging is easily distinguishable from dementia.
It is generally not very progressive and does not affect daily function.
Examples include forgetting where one left the keys or some items on the shopping list at the grocery store.
There are other medical conditions that can mimic dementia. One is delirium.
Delirium is a condition of confusion and an altered sense of awareness of one’s surroundings.
Delirium is often associated with an underlying medical condition, such as an infection, metabolic issue, or prolonged hospitalization.
The time course of delirium (much shorter) and the fluctuations in attention are characteristic and distinguishable from dementia.
Vitamin deficiency, specifically of Vitamin B12 can contribute to dementia, so this should be checked and supplemented if low.
Thyroid tests, and sometimes HIV or syphilis testing is done to make sure symptoms are not due to these other treatable medical conditions.
Depression is an important mimic of dementia. In fact, depression causing dementia has been named “pseudodementia” or “dementia of depression.”
This is because people with uncontrolled depression may exhibit signs similar to dementia (physical and cognitive slowing, giving poor effort, being unable to function in activities of daily life).
It is crucial to recognize pseudodementia because it can be treated and reversed with appropriate psychiatric and psychological care.
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