Whether we know someone with a type of dementia, we are a caregiver for a loved one with memory loss, or Alzheimer's runs in our family, many of us have been impacted by some form of dementia. According to the World Health Organization (WHO), about 50 million people worldwide struggle with dementia.1 As we age, dementia becomes a more and more familiar topic.
This guide will cover dementia's definition, symptoms and diagnosis, types of care, and more. Whether you are worried that a loved one may have dementia or you're a caregiver for someone with memory loss, it's important to understand these essential topics.
What is the difference between dementia and Alzheimer's disease? These terms are often used interchangeably, but they are not the same. Dementia is not a specific disease but an umbrella term for different conditions that cause progressive problems with thinking or memory. Alzheimer's disease is one type of dementia.
Dementia is progressive problems with cognitive functioning that interfere with a person's ability to handle tasks of everyday living. Symptoms may be subtle at first and develop over time before they get severe enough to interfere with functioning.
When symptoms are present but the person is still well enough to do all of their usual activities, they might have mild cognitive impairment, or mild neurocognitive disorder. When they begin to have difficulties with tasks such as working, managing their finances, or driving, they are considered to have crossed the threshold into dementia, which is also called major neurocognitive disorder. Cognitive functioning has multiple domains, such as these:
There are many causes of dementia. Alzheimer's disease is the best known and one of the most common. Other subtypes of dementia include vascular dementia, dementia with Lewy bodies, Parkinson's disease dementia, corticobasal degeneration, and primary progressive aphasia.
While the treatments available for dementia are limited, and there is no way to cure these conditions, understanding the subtype(s) causing the symptoms is still helpful, because it allows patients and their families to plan and get appropriate care. Doctors may perform different kinds of tests to diagnose the cause of the dementia depending on the person's symptoms. Sometimes a person has more than one type of disease causing their dementia symptoms; in this situation, they have what's called “mixed” dementia.
Some kinds of injuries, illnesses, or medical treatments can cause damage to the brain that affects cognitive functioning. When those changes occur at the time of the brain damage and stay stable afterward (do not get worse), they are not considered dementia, even if the changes are severe enough to interfere with daily function.
While dementia is not reversible, some reversible conditions can show up with similar symptoms. Therefore, anyone with memory loss or changes in thinking should get evaluated for other causes of their symptoms. If the cause does turn out to be dementia, it is helpful to figure out which type of dementia so that the right treatments can be given. It can also help optimize quality of life and help patients and their families plan for senior care.
Someone experiencing changes in memory may talk to their primary care provider, whether a general internal medicine doctor, a family practice doctor, or a geriatrician. They may also see a specialist in general neurology, behavioral neurology, memory disorders, geriatric psychiatry, or neuropsychiatry. The doctor will want to know about the details of the illness and perform an exam. Here is an overview of what to expect at this initial exam.
The doctor will likely ask about the following:
The doctor may perform a general physical exam to look for changes that might signal a different medical cause. Then he or she will likely perform a neurological exam. This includes assessment of the following:
At the end of the visit, the doctor will likely have some idea of what could be wrong but will probably need you to complete some tests before diagnosis.
Laboratory tests can help identify some common causes of cognitive changes. These might include blood tests, urine tests, and tests of the spinal fluid (cerebrospinal fluid, or CSF) to measure the following:
Along with lab tests, brain scans can be informative. There are a few types of brain scans the doctor may recommend.
The first scan the doctor will recommend to evaluate cognitive changes is often an MRI (magnetic resonance imaging), which looks at the brain's structure. If there are abnormal changes in the brain's shape, such as certain regions being thinner or smaller than expected, this can help identify the likely problem, especially in combination with the symptoms. Brain MRIs can also rule out the possibility of another cause for the changes, such as a tumor or stroke.
Some people getting evaluated for brain changes will also get a PET scan (positron emission tomography). PET scans use radioactive molecules to stick to something that will go into the brain, and then the picture can be taken with a special camera. There are different types of PET scans.
In FDG-PET, radioactive fluorine is attached to a special sugar that is taken in by brain cells. By looking at where the radioactive sugar shows up in the brain, doctors can tell which parts of the brain are active. PET scans can also be done using Pittsburgh compound B, which attaches to amyloid in the brain and can help identify Alzheimer's disease. However, this is not yet widely available.
A SPECT scan, or single-photon emission computerized tomography, uses radioactive compounds to measure brain blood flow. DaT scans, or dopamine transporter scans, are used to identify Parkinson's disease.
If any abnormal movement symptoms are repetitive, or there are any repetitive changes in awareness, an EEG may be performed to see if seizures are occurring. Seizures can be a cause of changes in cognitive functioning, but they can also occur alongside the onset of dementia.
Often, people with cognitive changes will undergo a comprehensive evaluation of their thinking and memory. This is called a neuropsychological assessment or neuropsychological evaluation, and a neuropsychologist usually performs it. Tests may be done with paper and pencil or a computer. The tests measure executive function, learning, memory, language, visuospatial function, and motor function. These tests can take a long time, often two to three hours.
None of the tests described here are diagnostic by themselves. Instead, doctors look at all of the tests and symptoms together to figure out the cause of the problems.
The symptoms of dementia develop as different parts of the brain stop working properly. As a result, dementia symptoms can vary greatly, depending on which parts of the brain are affected and not working properly. These are some common early symptoms:
These are some common later symptoms of dementia:
In general, people with dementia do better in familiar environments with familiar people. These are a few ways to help create consistency and familiarity for those with dementia.
There are several types of dementia, each with its own set of symptoms. The main dementia subtypes are covered in more detail below.
Symptoms of Alzheimer's disease usually show up as memory problems first and gradually progress to include other types of cognitive problems. People with Alzheimer's may ask the same questions repeatedly because they do not remember the answers. They may also repeat themselves, sharing the same stories or information because they do not recall telling them. Usually, people with Alzheimer's forget things that happened recently more often than things that happened a long time ago. For instance, they might accurately remember their childhood or young adulthood but not recognize grandchildren or recall where they have lived in retirement.
Treatment for Alzheimer's disease includes medications. Cholinesterase inhibitors are medicines that boost levels of acetylcholine, a neurotransmitter essential for thinking and memory. These medications are recommended for mild to moderate Alzheimer's disease. The NMDA receptor antagonist memantine is indicated for moderate to severe Alzheimer's disease, either alone or with a cholinesterase inhibitor. These medications do not reverse the effects of the disease, but they can improve someone's thinking and functioning in the short term.
Parkinson's disease usually first shows up as changes in how the person moves. The person may move and walk more slowly and turn around with lots of little steps instead of in one smooth movement. They may also start walking faster and faster until they are almost running. They may appear stooped or bent over. While walking, they may swing their arms less than a person usually does. This symptom often starts on one side of the body.
The person's face may become expressionless. Their handwriting may become smaller. Tremors may occur; this is sometimes described as a “pill-rolling tremor,” where the person's thumb moves in a circular motion near the first two fingers. The person's muscles may become stiff and not move as easily.
In Parkinson's disease, the brain cells that produce dopamine are not working anymore, so treatment centers on providing dopamine to the brain. Different kinds of medications can help with this, but the most common medication for Parkinson's disease is a combination of levodopa and carbidopa.
Lewy body dementia, also called dementia with Lewy bodies (DLB), often shows up with movement problems similar to those described above for Parkinson's disease, called “parkinsonism.” These include slow movements, stiff muscles, and a more expressionless face.
However, in DLB, the person also often has changes in their alertness and attention. They may appear normal at certain points of the day, while they lapse into staring spells or talk nonsensically at other points; they may also take long naps. Visual hallucinations – seeing things that are not there – are among the most dramatic symptoms of DLB. Often, the person will see people or animals. During sleep, someone with DLB may act out their dreams violently, and they may accidentally kick or hit their bed partner or knock items off their bedside table. This is called REM sleep behavior disorder. DLB can also disrupt some of the body's basic maintenance systems, so constipation and lightheadedness when standing can occur.
Treatment for Lewy body dementia can try to address all of the different symptoms the person is experiencing, including problems with movement, attention, hallucinations, and sleep. People with DLB often respond well to cholinesterase inhibitors, even though these drugs were initially developed for Alzheimer's disease. Melatonin may be helpful for sleep problems; clonazepam is sometimes used for sleep behaviors as well. Antipsychotic medications are generally not recommended for people with DLB, even those with hallucinations, because of the risk of serious sensitivity reactions and even death.
Vascular dementia (sometimes called multi-infarct dementia) is caused over time by damage to the brain's blood supply. This can happen through damage to very tiny blood vessels throughout the brain, from strokes (cerebrovascular accidents), or from a combination of these. Without a good blood supply, the brain cells cannot survive.
The symptoms of vascular dementia often include trouble with attention and executive functioning, such as planning and organizing behavior, and learning and “pulling out” stored information. However, symptoms associated with vascular dementia can vary with what parts of the brain have been damaged by poor blood supply. For example, if the person had a stroke that affected the language parts of the brain, they might be aphasic (unable to speak). In contrast, if they had a stroke that affected the vision parts of the brain, they might be unable to process visual information. Worsening of vascular dementia sometimes occurs in a “stepped” fashion, with abrupt worsening separated by periods without much decline.
Vascular dementia care often focuses on prevention, which includes preventing it from getting worse. This can mean preventing risk factors for developing vascular dementia, such as high blood pressure, high cholesterol, and diabetes. A healthy diet with many fruits and vegetables and minimal saturated fats is helpful. Exercise is also effective. Smoking is very damaging to blood vessels, so avoiding (or quitting) this is important. Medications are often given to lower blood pressure and cholesterol levels and to treat diabetes. After someone has a stroke, rehabilitation therapies are valuable to help regain lost functions or learn to compensate for them. These might include physical therapy to improve balance, speech therapy to regain speech or make it clearer, or cognitive rehabilitation to develop memory aids for absentmindedness or forgetfulness.
Frontotemporal lobar degeneration (FTLD) includes both language and behavioral variants. Language variants, such as semantic dementia and agrammatic progressive aphasia, may show up as problems with speech and writing, including difficulties naming or identifying objects, understanding the meaning of words, following grammar rules, or even just producing speech.
Behavioral variant FTLD (bvFTLD) manifests as changes in behavior. These changes can include loss of sympathy or empathy, disinhibition, apathy (not caring about things), change in food preferences (especially eating more sweets), and becoming very rigid or stuck on doing things exactly one way. They might also have problems with executive functioning, including distractibility and disorganization.
With limited treatments available for FTLD, care often focuses on preventing problems that could develop from their behavior. Family and caregivers might find it very stressful to care for someone with bvFTLD. Learning about the symptoms of this disease and finding support (support groups, emotional support, or education on how to manage the person affected) can be helpful.
It may help to allow the person to continue with harmless behaviors (such as sorting and ordering items in the home) while distracting them from problematic ones (touching strangers). It can be important to limit the person's ability to cause lasting damage, such as by restricting their access to financial resources. Rewards can encourage desired behaviors. Selective serotonin reuptake inhibitor medications may help with rigid behaviors. Agitation is sometimes treated with antipsychotic medications, but at low doses due to the risk of death. Cholinesterase inhibitors are not helpful in cases of bvFTLD. Genetic testing may be done if an inherited syndrome is thought to be present; this can help families think about risk in children or other relatives of the affected person.
There are more types of dementia than are described here. For information on other subtypes of dementia, consult your doctor or reputable websites such as the Alzheimer's Association.
Jessica Harder, M.D., is a trained neuropsychiatrist treating a wide range of acquired and inherited brain disorders, as well as a researcher studying mood, cognition, inflammation, and hormones. Dr. Harder earned her undergraduate degree in psychology from Harvard, where she performed research… Learn More About Jessica Harder
Since graduating from Harvard with an honors degree in Statistics, Jeff has been creating content in print, online, and on television. Much of his work has been dedicated to informing seniors on how to live better lives. As Editor-in-Chief of the personal… Learn More About Jeff Hoyt
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World Health Organization. (2020). Dementia.