Medically Reviewed

The Many Types of Dementia

A range of brain diseases and conditions can cause symptoms of dementia. We help you understand the most the common ones.

Updated Oct 4, 2024

By

Courtney Southwick

Medical ReviewerShaheen Lakhan, M.D.

Our Experts: Zoe Arvanitakis, M.D.; James R. Bateman III, M.D., MPH; Mary Sano, Ph.D.

Zoe Arvanitakis, M.D.Medical Director; Professor of Neurological Studies Rush Memory Clinic; Rush Medical College Chicago

James R. Bateman III, M.D., MPHAssistant Professor of Neurology and Psychology Wake Forest School of Medicine Winston-Salem, NC

Mary Sano, Ph.D.Director of the Alzheimer's Disease Research Center and Professor of Psychiatry Icahn School of Medicine at Mount Sinai New York City

It doesn’t matter if you’re age 30 or 60, you may be afraid of losing your memory as the years tick by. In fact, recent research shows that dementia is second only to cancer when people list their biggest fears about getting older. But not everyone develops dementia—in fact, dementia is not considered to be a normal part of aging.

What’s more, dementia isn’t even a disease. Instead, it’s the term doctors use to describe cognition and memory-related symptoms that are serious enough to interfere with your daily life. There are many different types of dementia, and we’re going to help you understand what they have in common and how they’re different. That can make a difference in arriving at a diagnosis and getting the right treatment.

Roughly 9% of Americans over 65 have some form of dementia, and the vast majority of them (about 60% to 80% from this group) have Alzheimer’s disease (AD). Other common forms include:

• Childhood dementia

• Chronic traumatic encephalopathy (CTE) dementia

• Creutzfeldt-Jakob disease

• Early-onset Alzheimer’s disease

• Frontotemporal dementia

• HIV-associated dementia (HAND)

• Huntington’s disease

• Lewy Body dementia

• Mixed dementia (likely more common than experts once thought, especially in people over age 90, and usually a combination of AD and vascular dementia)

• Parkinson’s disease dementia

• Posterior cortical atrophy

• Vascular dementia

Now, let’s take a look at each one:

Again, most people with dementia have Alzheimer’s disease, which gets worse over time. In the mildest stages of AD, you may have trouble driving (because you get lost) and doing complicated tasks (like bill-paying); later on, you become confused, have trouble taking care of yourself, and may be prone to outbursts.

Alzheimer’s Disease Causes

Most scientists connect the abnormal buildup and spread of two proteins in the brain, known as beta-amyloid and tau, as the main culprits behind the chronic neuroinflammation and cognitive decline that are associated with Alzheimer’s symptoms.

Alzheimer’s Disease Risk Factors

AD specialists generally cite the following risk factors for developing this neurodegenerative disorder:

• Advancing age

• Genetics (in particular, possessing the APOE4 gene)

• Having high blood pressure and/or type 2 diabetes

• Lifestyle habits that are bad for your heart health (like heavy drinking, smoking/vaping, and being sedentary, a.k.a., not moving enough)

Alzheimer’s Disease Symptoms

Alzheimer’s often comes with warning signs that become increasingly easier to notice. They include:

• Difficulty finding words

• Losing objects and your way

• Repeating the same question over and over again

• Then, as AD progresses, increasing problems communicating and understanding, more apathy and personality changes, plus more confusion and wandering

Alzheimer’s Disease Diagnosis

To diagnose Alzheimer’s, your doctor will usually:

• Conduct a complete medical history

• Do blood and urine tests (to rule out more benign reasons for losing your memory, like a thyroid condition or low vitamin levels)

• Do imaging tests to rule out brain bleeds, tumors, or signs of a stroke.

• Order tests to detect beta-amyloid and tau proteins, although these are only done if the doctor isn’t sure you have AD or some other type of dementia

Alzheimer’s Disease Treatment

Remember, Alzheimer’s disease is a progressive neurodegenerative disorder without a cure. Typical treatments for AD may include:

• Cholinesterase inhibitors. These drugs can temporarily boost memory for as long as a year or two in the mild stages of AD and improve day-to-day function and behavior in later stages. They include the medications Aricept (donepezil) and Namenda (memantine), which may also help with confusion, behavior, and attention, as well as Razadyne (galantamine).

• Monoclonal antibodies. These new medications, such as Kisunla (donanemab) and Leqembi (lecanemab), are the first drugs that can stymie the progression of AD by slowing down decline in memory, thinking, and even daily function.

• Staying active. Physical exercise can help improve thinking skills and improve your mood and quality of life, even in people with moderate Alzheimer’s.

After Alzheimer’s, this is the second-most-common form of dementia, and it’s the type you can do the most about, even into your 60s. If your blood pressure, cholesterol, and blood sugar levels are in a healthy range, you’re less likely to have a stroke (or a mini-stroke) or to damage the blood vessels in your brain—all of which can interrupt the flow of oxygen and nutrients to the brain and cause cells and tissue to die off. The Alzheimer’s Association estimates that about 5% to 10% of people with dementia have vascular dementia only (versus having mixed dementia with AD).

Vascular dementia can be mild or severe. It can get worse over time, but that decline is described as occurring in “stepdowns”—it gets worse, then it stays the same, then it gets worse again, because you have another stroke or a heart attack, or you require surgery. If your vascular dementia is caused by damaged blood vessels (and not by strokes), then the decline can look more like Alzheimer’s—a gradual worsening.

Vascular Dementia Causes

Often a stroke—a large one or several small or even silent ones—block the arteries and cause cells to die off. But not all strokes cause vascular dementia (which affects thinking, reasoning, and memory, so you can’t go about your daily life). It depends on what part of the brain is being deprived of blood. Other causes include progressive small-vessel disease, in which the blood vessels in the brain get narrower or are damaged because of age, high blood pressure, and/or diabetes.

Vascular Dementia Risk Factors

In general, vascular dementia specialists agree on the following risk factors for developing this type of dementia:

• Age (your blood vessels stiffen and harden as you get older)

• Being overweight

• Eating too much processed foods

• Excessive drinking (more than 14 drinks per week)

• High blood pressure

• High blood sugar level

• High cholesterol

• Lack of exercise

• Smoking

Vascular Dementia Symptoms

If dementia occurs after a stroke, it depends on the part of the brain that is affected. While you may not have the memory loss that AD brings, you may experience:

• Aphasia (problems with language and speech)

• Confusion

• Disorientation

• Loss of attention, focus, and judgment if the cause is progressive small-vessel disease

• Loss of concentration

• Mood issues such as feeling apathetic or depressed

• Personality changes

• Trouble making decisions or reasoning

• Trouble walking—you may shuffle more and be unsteady on your feet

Vascular Dementia Diagnosis

If you’ve had a major stroke, then a doctor can pretty much tell that’s the cause. Otherwise, a provider will:

• Ask for your medical history (including a family history of strokes and other symptoms)

• Do a series of memory tests

• Give you imaging tests, like CT scan or MRI, to check for blood vessel damage and signs of brain bleeds

• Order blood work (to check cholesterol and blood sugar levels)

Vascular Dementia Treatment

There are no FDA-approved drugs for vascular dementia, but Aricept (donepezil) can help attention and focus. The other drugs for Alzheimer’s have had mixed results. What seems to be more beneficial are lifestyle changes that can help prevent another stroke or more damage and slow the rate of decline down.

Here are the things you can do to slow dementia progression:

• Eat a heart-healthy or low-sodium diet such as the Mediterranean or DASH diets

• Get blood pressure and cholesterol under control, either by taking your meds or getting an Rx for new drugs from your provider

• Get 20 to 30 minutes of exercise (walking, dancing, gardening) as many days as you can

• Take a low-dose aspirin every day to prevent heart attacks or strokes if your doctor thinks it’s right for you

Most people heard about this form of dementia after the actor Robin Williams died, when his wife revealed the beloved comedian/actor’s cause of death. But Lewy Body dementia is actually the umbrella term for two types of related dementias—dementia with Lewy bodies (DLB) and Parkinson’s disease dementia.

People with DLB and Parkinson’s disease dementia both have abnormal clusters of a particular protein in their brain that develop into something called Lewy bodies. But while the earliest signs of these two types of dementia are different, later on the symptoms are pretty much the same. The difference is timing—people with Parkinson’s disease dementia develop Parkinson’s disease first (the tremors, the shaking limbs) and then develop the signs of dementia.

About 1.4 million Americans have DLB, comprising roughly 5% of all people over 65 with some type of dementia. Like Alzheimer’s, it’s considered neurodegenerative, meaning the cells in the central nervous system stop working and eventually die. Because early symptoms are similar to AD or look like psychosis, people with DLB are frequently misdiagnosed. When you have DLB, you can also develop tremors and issues with walking, so people are sometimes misdiagnosed with Parkinson’s.

Dementia with Lewy bodies worsens over time, and like AD, there are stages, although they aren’t as clear-cut as the ones in Alzheimer’s, mainly because DLB hasn’t been studied as extensively as Alzheimer’s has. There’s no cure, and no specific treatment, either, for this disease.

DLB Causes

In a healthy brain, alpha-synuclein proteins help neurons (brain cells) communicate with one another. But for some reason, these proteins begin to clump together inside the neurons, causing them to communicate less effectively and eventually die; it happens first in the cortex, the area of the brain that controls the processing of information, language, and perception. Lewy bodies also mess up the production of certain brain chemicals known as neurotransmitters, including dopamine (which plays a role in muscle movement) and acetylcholine (which is key in memory formation and sleep regulation).

DLB Risk Factors

Generally, risk factors for DLB include:

• Age

• Being male

• Family history of Parkinson’s disease

• Genetics—as in AD, there is evidence that having the APOE4 gene can up your odds of developing DLB

• History of anxiety and depression

DLB Symptoms

One of the earliest DLB symptoms is a sleep disturbance known as REM sleep behavior disorder, where you literally act out your dreams—you thrash, you kick, you pull your partner’s hair, you scream, you fall out of bed. This happens years and even decades before any of the other cognitive symptoms. Unlike Alzheimer’s, you don’t lose short-term memory, though memory loss can come at a later stage.

Other signs of DLB include:

• Daytime sleeping

• Depression, apathy, and delusions (which is why people can be misdiagnosed with a psychiatric disease)

• Difficulty with motor skills, including tremors and shakes, shuffling, falling/loss of balance, and/or stiffened muscles, which are also signs of Parkinson’s disease; in DLB, such symptoms come after dementia sets in, or at the same time, but not before, and they occur in the early stages (unlike in AD, when a shuffling gait is a sign of moderate or severe disease)

• Dizziness, fainting, drops in blood pressure, urinary incontinence

• Hallucinations that can be extremely lifelike

• Loss of visual-spatial skills, meaning that you have trouble processing how things are organized in space, i.e., you can’t find the bathroom in a house that you’ve lived in for years, or you open the fridge to get the milk and keep reaching in the wrong direction to pull out the butter instead

• Waxing and waning alertness and attention, which can occur day by day for some, while others experience such symptoms at certain times of the day

DLB Diagnosis

There’s no test that can spot Lewy bodies in the brain while you’re alive. Instead, neurologists tease out a diagnosis based on symptoms and medical history. If a specialist isn’t sure, you might get an imaging test known as a DaTscan. A radioactive tracer is injected into your bloodstream, goes into your brain, and attaches itself to the dopamine transporter. Then you get a scan. If you have DLB (or Parkinson’s) the scan will show lower levels of dopamine.

DLB Treatment

Currently, there is no FDA-approved treatment for DLB. Doctors often try:

• Aricept (donepezil), which can be very effective (if only for a year or so) to help boost attention and alertness and decrease hallucinations

• Klonopin (clonazepam) to treat sleep disorders

• Medications to treat muscle stiffness and tremors, such as Rytary or Duopa (carbidopa-levodopa), but these meds can sometimes make hallucinations worse

• Physical therapy and staying active can help improve balance and problems walking

• Rarely, antipsychotics for hallucinations and delusions—many of them can make symptoms worse, though Seroquel (quetiapine) is sometimes effective. Instead, doctors try to treat hallucinations with nonpharma strategies like music therapy, distractions, or keeping to a routine

• SSRIs including Prozac to treat depression and/or anxiety

About 2% of Americans, usually between ages 50 and 85, develop Parkinson’s disease, a neurodegenerative brain disorder that gradually gets worse over time and affects your ability to move and speak normally. People with Parkinson’s shake even when they’re still, have stiff arms and legs, and have trouble with balance and walking and sometimes, cognition and speech. About 70% develop some type of cognitive impairment and dementia, because the disease spreads to the parts of the brain involved in thinking and memory at least a year (and often several years) after the stiffness and tremors.

Parkinson’s Disease Dementia Causes

The causes of PD dementia are similar to dementia with Lewy bodies—clumps of alpha-synuclein proteins take over brain cells, forming Lewy bodies. The Lewy bodies start in the part of the brain that controls muscle movement and then spreads.

Parkinson’s Disease Dementia Risk Factors

Risk factors for dementia associated with Parkinson’s disease typically include:

• Advancing age (the older you are, the higher your risk)

• Being a male

• Experiencing serious motor symptoms

• How long you’ve had Parkinson’s (the later the stage, the higher the risk)

Parkinson’s Disease Dementia Symptoms

The symptoms are similar to dementia with Lewy bodies and include:

• Anxiety, irritability, and/or depression

• Confusion

• Hallucinations and delusions

• Paranoia

• Trouble concentrating and focusing

• Trouble sleeping and/or disturbed sleep cycles

• Trouble solving problems and learning new things

Parkinson’s Disease Dementia Diagnosis

The first step in diagnosing PD dementia is conducting tests to exclude other conditions, such as thyroid problems or low vitamin levels, which can sometimes mimic dementia. Your health care provider may change your medications, since some drugs that block acetylcholine—a brain chemical that is already low in people with Parkinson’s disease—may mimic dementia symptoms. Oftentimes, removing the medication can reverse the problem. In addition to running tests, your health care team may perform neuropsychological tests or order imaging tests, such as CT and MRI scans.

Parkinson’s Disease Dementia Treatment

Similar to DLB, there is no FDA-approved treatment for Parkinson’s disease dementia yet but some medications can help manage its symptoms. In addition, deep-brain stimulation has been shown to be helpful in some cases, but not all. Medications include:

• Cholinesterase-inhibitors for treating cognitive issues

• Exelon (rivastigmine) for memory or attention issues

• Melatonin or Klonopin (clonazepam) for sleep disorders

• Rytary (carbidopa-levodopa) for movement issues, though it may worsen dementia symptoms

• SSRIs for mood disorders

Frontotemporal dementia (FTD) is another umbrella term for a group of progressive brain diseases that affect your personality and your ability to think and speak. Roughly 60,000 Americans have FTD with half of them having the type that affects behavior, while the other half have the type that affects language.

Over 60% of those patients are between the ages of 45 and 64, so being (relatively) young is one way that doctors help determine whether you have FTD. The disease is still misdiagnosed, though, since doctors may think you have a psychiatric disorder if you have the type that affects behavior, or Alzheimer’s if you have the type that affects language. In general, it takes about three to four years to get a diagnosis, according to the Association for Frontotemporal Degeneration.

FTD that affects your personality is called behavioral variant frontotemporal dementia (bvFTD).

FTD that affects only your ability to communicate is called primary progressive aphasia (PPA), and this form is broken down further into three types:

• Semantic PPA. This type cause an inability to understand and form words.

• Nonfluent PPA. This type causes an inability to complete thoughts in a coherent and grammatical fashion, often with missing words, or tenses and pronouns being wrong.

• Logopenic progressive aphasia. This is an impairment in naming things with sentence repetition.

Like other dementias, FTD gets worse over time. It can affect your muscles and balance (you may have trouble swallowing and walking), which can leave you in a wheelchair. On average, people die eight years after being diagnosed and die from an infection, like pneumonia.

FTD Causes

Several different types of proteins (including tau proteins) begin to clump in the frontal and temporal lobes of your brain (which are located in the front and sides of your head). These brain regions affect your behavior, language, and organizational and planning skills. As the clumps get bigger, they kill off cells, causing those parts of the brain to shrink.

FTD Risk Factors

Genes play a big role in FTD, and around 30% of the cases occur because someone in your family had it. One genetic mutation, the C9orf72 gene, can cause FTLD as well as ALS (Lou Gehrig’s disease). Another risk factor? Repeated concussions. So far, the studies showing evidence that diabetes or blood pressure play a role in FTD have been mixed.

FTD Symptoms

It depends on the type of FTD you have, but many times symptoms overlap—or they look like one type of FTD in the beginning and a few years later develop into symptoms of another type.

Signs of FTD include:

• Your behavior becomes inappropriate and impulsive, which means anything from blurting out rude or offensive comments, shoplifting, touching strangers,or standing uncomfortably close to people.

• You become indifferent or apathetic about things you used to love, like hobbies or work.

• You no longer show empathy or sympathy for others, including family members.

• You get a craving for carbs, sometimes eating, say, three boxes of Pop-tarts a day or binge-eating candy all the time.

• You do certain ritualistic things over and over, whether it’s pacing, saying a word or a phrase, clapping or rubbing your hands (similar to ritualistic, obsessive-compulsive-disorder behaviors, minus the obsessive thoughts behind them).

• You have trouble making good decisions, solving problems, and organizing, which can all lead to mistakes on the job or taking financial risks.

PPA symptoms include:

• In semantic PPA, you lose the concept of words and what they mean. So, if someone shows you a pen, you not only don’t know the word for pen, you don’t know what a pen is. Later on, your personality may change (you become more rigid), and you may lose knowledge of abstract concepts like love and happiness.

• In nonfluent PPA, you lose the physical ability to form words, so you have trouble speaking complete sentences and/or speaking ungrammatically, leaving off words, articles, and mixing tenses. Your understanding of complex words, sentences, and ideas goes downhill too. You can stop speaking altogether and have problems with your muscles, so you can no longer swallow.

• You may also have signs of muscle weakness, tremors, stiffness, loss of balance. If you have these symptoms first, you probably have another type of frontotemporal degeneration that’s more similar to ALS, and develop a decline in thinking, behavior, and language skills later.

FTD Diagnosis

Doctors will ask you for a thorough medical history, so it pays to bring along someone close to you (a partner, a relative) who can discuss your symptoms. That helps a doctor form a hypothesis, along with other factors (such as your age) that can be confirmed by other tools, including:

• Cognitive tests to test your memory (and to rule out more common forms of dementia, like Alzheimer’s)

• Flurodeoxyglucose positron emission tomography (FDG PET) helps doctors see how your brain is working. You get a radioactive tracer containing sugar via an IV, and then doctors measure the way your brain metabolizes glucose (which it needs for energy). That helps a doctor see the levels of activity in the frontal and temporal lobes—if there are lower levels of activity, it means those parts of the brain aren’t working as well.

• MRI scan to check if the frontal or temporal lobes have shrunk

FTD Treatment

There’s no cure for FTD and no FDA-approved treatment. The drugs used to treat Alzheimer’s, including Aricept (donepezil) and Namenda (memantine) can make people with FTD worse. Most of the time, meds are used to treat individual symptoms:

• Anti-depressants such as Zoloft (sertraline) for the OCD-like ritualistic behaviors and to control the binge-eating, usually in high doses

• Anti-psychotics like Seroquel (quetiapine) for the impulsive or anti-social behaviors, usually in low doses

When people have more than one type of dementia, it’s called mixed dementia, and experts now think it’s way more common than originally thought, especially in people in their 80s and beyond.

Typically, those with mixed dementia have Alzheimer’s and vascular dementia, but people can have AD and dementia with Lewy Bodies, too, or several other types of combinations. A small study suggested that as many as 19% of patients with dementia have multiple pathologies, meaning brain changes that are found in multiple types of dementia.

Researchers from Rush University in Chicago examined the brains of 1,000 patients who had taken part in memory studies over the course of 22 years or more and had died in their late 80s. About two-thirds of them had been diagnosed with mild cognitive decline and/or dementia (typically Alzheimer’s). But when scientists examined their brains, 94% showed signs of brain disease, whether it was the plaques and tangles of Alzheimer’s, signs of small strokes, or Lewy bodies. Of this cohort, 78% showed signs of two types of brain disease, 58% showed signs of three, and more than a third (35%) had four or more conditions that could affect their thinking and memory. So, while Alzheimer’s might be the most common form of brain disease, it rarely existed on its own.

This is especially true for African-Americans, another study done by Rush University found. After examining the brains of 122 Alzheimer’s patients after they’d died, researchers found that roughly 71% of black patients versus roughly 51% of white Europeans had mixed dementia—usually a combination of Alzheimer’s, dementia with Lewy Bodies, and signs of strokes—even when accounting for gender, education, and age differences.

While scientists are still learning about mixed dementia, it appears that those who have it are more likely to have worse outcomes and a more rapid decline. Evidence shows that you’re more likely to have symptoms if you have more than one type of dementia.

Causes of Mixed Dementia

A combination of factors, from cardiovascular disease that can damage the arteries feeding into the brain to too many plaques and tangles can contribute to the development of mixed dementia, many scientists believe. Experts now speculate that the more conditions you have, the more likely you are to suffer cognitive decline.

Mixed Dementia Risk Factors

The same as many of the brain diseases described here—from family history/genetics to heart disease and diabetes—are risk factors for mixed dementia. Not getting enough physical activity, a diet low in fruits and vegetables, and smoking can all up your risk too, mainly because it contributes to a higher chance of developing high blood pressure and diabetes.

Mixed Dementia Symptoms

Again, your symptoms depend on what combination of diseases you have. For example, you might be having memory loss because of Alzheimer’s and then have a stroke that accelerates the memory loss and tips you into dementia.

Mixed Dementia Diagnosis

Most mixed dementias are discovered only after death, and only if you donate your brain to science. So doctors tend to diagnose the most dominant form of dementia based on medical history, symptoms, and test results (like MRIs and scans).

Mixed Dementia Treatment

For those who are diagnosed with mixed dementia during their lifetimes, doctors try for a comprehensive approach, depending on the conditions they think are contributing to the dementia.

Most often, they’ll:

• Prescribe meds approved for Alzheimer’s (like Aricept or another cholinesterase inhibitor), which also seem to work for vascular dementia and dementia with Lewy bodies

• Treat symptoms of mixed dementia accordingly, whether it’s the sleep disorders of DLB or controlling cardiovascular health

Creutzfeldt-Jakob disease (CJD) is the most common prion disease, occurring when prion proteins in the brain begin folding into abnormal shapes. These misfolded proteins in the brain damage brain cells, which leads to symptoms of dementia as well as trouble with normal muscle movement. CJD is extremely rare, occurring in about one person in 1 million. While most types of dementia progress slowly, CJD-associated dementia worsens rapidly.

CJD is related to the bovine spongiform encephalopathy, the disease found in cows commonly called mad cow disease. Experts generally divide CJD into three types:

• Acquired CJD. This is the only type of CJD that you can get from an outside source. It’s extremely rare; usually only 1% of cases are acquired. This is caused by coming in contact with contaminated medical instruments or transplanted tissues, or—even more rarely—eating food products from contaminated cows.

• Familial CJD. This form is caused by a gene and is found in 10% to 15% of cases. The gene must be passed down from a parent. With familial CJD, symptoms start earlier in life, sometimes as early as your 20s.

• Sporadic CJD. Some 85% of CJD cases are sporadic and have no clear cause. With this type, symptoms usually begin around age 60 to 65.

Creutzfeldt-Jakob Disease Causes

The cause depends on the type of CJD you have. In the large majority of cases—about 85%—there is no known cause. In rare cases, people inherit the disease from a parent, and in even more rare instances, you can become infected with CJD.

Creutzfeldt-Jakob Disease Causes Risk Factors

The only known risk factor is the genetic predisposition found in a few families. Scientists have identified 50 prion mutations that make it more likely you will develop familial CJD. With sporadic CJD, age may be a risk factor because it usually happens after age 60. Professionals such as butchers who handle raw meat do not have a higher risk of developing acquired CJD compared to the general population.

CJD Symptoms

While they can vary from person to person, common symptoms of CJD-related dementia include:

• Agitation

• Depression

• Difficulty with memory, thinking, and judgment

• Disorientation

• Double vision or hallucinations

• Mood swings

• Problems with normal muscle movement, such as stiffness or involuntary movements

• The eventual inability to talk or move your body

CJD Diagnosis

Genetic tests can determine whether you have familial CJD. There are no tests that can tell you that you have sporadic CJD, but your healthcare provider can diagnose you based on the following:

• Asking questions about your symptoms; CJD dementia progresses rapidly, which is usually the first clue

• Electroencephalogram, or EEG, can show any CJD-related changes to your brain’s electrical activity

• MRI scan of your brain can show CJD-related changes to the brain tissue

• Protein misfolding cyclic amplification (PMCA) test can help detect misfolded proteins

• Spinal tap, or lumbar puncture, can test your spinal fluid for proteins

CJD Treatment

At the moment, there are no treatments that are effective for any CJD type. Health care providers focus on alleviating the symptoms, which may include medications to ease pain and muscle stiffness. Unfortunately, 90% of those diagnosed with sporadic CJD have a one-year life expectancy. The life expectancy is much longer in those with familial CJD—up to 10 years.

Huntington’s disease (HD) is a genetic condition caused by a defective gene that makes a protein incorrectly—and this protein causes damage to the areas of the brain that are important for thinking, mood, and movement. While the use of the protein is not known, if you carry this gene, you will eventually develop Huntington’s disease. The affected gene for Huntington’s disease is a dominant gene, which means you only need one copy of the defective gene from one parent to have this disease.

Most of the time, symptoms of HD begin between ages 30 and 50, but some people have experienced the onset of symptoms as early as age 2 and as late as age 80. Many people with Huntington’s disease compulsively repeat behaviors or ask the same question over and over again, which is challenging for family members to deal with.

Huntington’s Disease Causes

A single defective gene on chromosome number 4. Normally, this gene repeats its genetic code up to 20 times, but with Huntington’s disease, the faulty gene repeats its code up to 40 times. Scientists aren’t sure why the extra repetitions lead to the symptoms of Huntington’s.

Huntington’s Disease Risk Factors

The only people who are at risk for Huntington’s disease are those who inherit the faulty gene from a parent.

Huntington’s Disease Symptoms

Most HD specialists agree that the most common symptoms are:

• Deterioration in skills such as reasoning, judgment, thinking, and planning

• Inability to concentrate

• Memory loss

• Mood changes, particularly depression, anxiety, irritability, and anger

• Obsessive-compulsive thoughts and behaviors

• Uncontrolled muscle movements in your arms, legs, upper body, head, and face.

Huntington’s Disease Diagnosis

A genetic test is available and can tell you if you have the gene for Huntington’s disease. If you haven’t had any symptoms but have a parent with the disease, you can still be tested for the gene.

Huntington’s Disease Treatment

There are currently no treatments that can stop or slow the progression of Huntington’s disease. The focus right now is on treating the symptoms.

Typical symptoms and possible treatments include:

• Medications that treat involuntary muscle movements like Xenazine (tetrabenazine) or Zyprexa (olanzapine)

• Medications that treat involuntary irritability, such as antidepressants called selective serotonin reuptake inhibitors (SSRIs), which may help mild cases; for severe cases that include threatening behavior, experts suggest atypical antipsychotic medications

• Medications that treat obsessive-compulsive thoughts such as SSRIs

This type of dementia is similar to Alzheimer’s disease and other types of dementia but is unique in one aspect: The changes to the brain occur in the outer layer of the brain called the cortex, but only near the back (posterior) of the brain. Oftentimes, it looks the same as Alzheimer’s disease and can be mistaken for it—but it’s in a different part of the brain than traditional AD. People with PCA show similarity to dementia with Lewy bodies or Creutzfeldt-Jakob Disease. A big difference between PCA and Alzheimer’s disease is that it is often diagnosed earlier in life—between the ages of 50 and 65.

It is difficult to know how many people are living with PCA because there’s no accepted standard definition of what it is. The posterior cortex is the part of the brain that processes visual information, so vision problems are usually the first symptoms and in fact, most people seek the help of an eye doctor first. Some scientists think PCA may be a variant of Alzheimer’s, though memory loss is rare until the later stages.

Posterior Cortical Atrophy Causes

Just like Alzheimer’s disease, PCA is caused by the same buildup of beta-amyloid and tau proteins in the brain. Why this happens is unknown. There are no genes that have been associated with PCA.

Posterior Cortical Atrophy Risk Factors

There are no known risk factors for PCA, and even though it is similar to AD, it is unknown if the two conditions share risk factors.

Posterior Cortical Atrophy Symptoms

The symptoms of PCA vary widely from person to person and can also change as the condition progresses. While PCA is still being studied, in general, it’s agreed that the following are common conditions.

• Difficulty distinguishing between a moving object and a stationary one

• Difficulty judging how far away something is

• Difficulty with math or spelling

• Difficulty with vision (like trouble reading)

• Disorientation

• Hallucinations

Posterior Cortical Atrophy Diagnosis

There are no treatments currently available to treat PCA, but there is some evidence that Alzheimer’s disease medications can also help with PCA. This has not been proven, however, and may differ from person to person. Oftentimes, physicians can diagnose the condition because there are vision problems with no physical problems in the eyes. Another clue is the younger age of onset before age 65.

Posterior Cortical Atrophy Treatment

There is disagreement about how to treat PCA, but scientists are working on diagnostic criteria right now that may lead to individualized treatment of your specific symptoms. Your health care provider may give you neuropsychological tests, imaging tests of your brain, blood tests, or other exams to diagnose PCA.

While most people who develop Alzheimer’s disease are over age 65, it can happen at younger ages. It’s uncommon, but if noticeable symptoms of dementia begin in your 40s or 50s, it may be early-onset Alzheimer’s disease. Out of the nearly 7 million Americans who are living with Alzheimer’s, it’s unclear how many people are under age 65. Early-onset Alzheimer’s may be mild, moderate, or severe.

Diagnosing early-onset AD is difficult because most healthcare providers are not looking for symptoms of dementia in people younger than 65. Oftentimes, people in their 40s and 50s who are experiencing early-onset Alzheimer’s disease are told their symptoms are due to too much stress. It’s common for someone with early-onset Alzheimer’s disease to go from doctor to doctor getting conflicting diagnoses.

Early-Onset AD Causes

Traditional AD is caused by a buildup of beta-amyloid and tau proteins in the brain. Scientists aren’t sure what causes early-onset Alzheimer’s disease, but there are rare genes that have been found in a few hundred families around the world. In these familial Alzheimer’s cases, those who carry the genes tend to develop symptoms as early as their 30s.

Early-Onset AD Risk Factors

The only risk factor known at this time is having the rare genes that are associated with familial Alzheimer’s cases.

Early-Onset AD Symptoms

The signs and symptoms of early-onset Alzheimer’s disease are the same as traditional Alzheimer’s in people over age 65. This can include feeling confused, repeatedly having trouble finding the words you mean to say, repeating questions, forgetting where you were heading, trouble communicating, and personality changes.

Early-Onset AD Diagnosis

Since many health care providers don’t think to look for Alzheimer’s symptoms in people younger than 65, seeing a medical provider who specializes in Alzheimer’s disease may be your best bet for getting an accurate diagnosis. Your health care provider will most likely ask for your medical history, and possibly conduct imaging tests and blood or urine tests to rule out other possibilities. They may also give you neurological or cognitive tests. If diagnosis proves difficult, there are tests available that can detect beta-amyloid and tau proteins.

Early-Onset AD Treatment

Early-onset Alzheimer’s disease may be treated similarly to traditional Alzheimer’s.

• Cholinesterase inhibitor medications, like Aricept (donepezil), Namenda (memantine), and Razadyne (galantamine), can boost your memory temporarily, and in mild stages, may even help for up to two years. These medications can improve your function day-to-day. Namenda can help improve symptoms like confusion and limited attention.

• Medications such as Kisunla (donanemab) and Leqembi (lecanemab) are the first drugs shown to slow down the progression of Alzheimer’s disease. Improvements can be seen in memory loss, clear thinking, and daily functioning.

• Regular exercise and other lifestyle changes (like consistent, quality sleep and healthy diet) can help improve symptoms, mood, and even quality of life.

Though uncommon, people in the later stages of HIV/AIDS can develop dementia that is associated with the viral infection. Anti-retroviral therapy (ART) is a group of medications that are prescribed to those with HIV infection. ART keeps the viral load in the body so low that often the virus is undetectable. Because the levels of the virus are this low, it’s very uncommon today for people who take ART to go on to develop HIV-associated dementia later in life.

Even though HIV-associated dementia is increasingly rare, some people living with HIV do develop mild cognitive symptoms. This is referred to as HIV-associated neurocognitive disorder (HAND).

HIV-Associated Dementia (HAND) Dementia Causes

HAND is associated with the HIV virus that causes AIDS. This type of dementia or cognitive impairment only occurs in people who have been living with the HIV virus for a long time. It is unknown how the virus affects the brain tissues.

HAND Dementia Risk Factors

The only known risk factor for HAND is to be living with HIV/AIDS.

HAND Dementia Symptoms

Symptoms that are typically associated with HAND include:

• Depression

• Difficulty with decision-making

• Irritability

• Memory loss

• Problems concentrating

• Problems with planning and organizing well

HAND Dementia Diagnosis

Diagnosing HAND is similar to diagnosing other types of dementia. With a physician who knows you are living with HIV, you may:

• Give the doctor a history of the symptoms you’re concerned with

• Undergo blood test or imaging scans

• Undergo neurological or mental status tests

HAND Dementia Treatment

Typically, HAND treatment includes:

• Starting ART medications if you have not already

• Prescription medications to help with symptoms such as depression

While dementia is often thought of as a condition associated with old age, there are more than 100 genetic diseases that cause dementia in children and teenagers. Childhood dementia can start when you’re a baby, child, or even a teenager. Childhood dementia is unique in that it progresses rapidly. Someone with childhood dementia will lose skills that they have learned, such as the ability to walk or talk. Eventually, the condition develops into total loss of body function and death.

The unfortunate fact is that there is very little research into childhood dementia so little is known about it. Half of all children diagnosed with any of these genetic conditions that lead to childhood dementia die before age 10, and the majority die before their 18th birthday. It’s estimated that one in 2,900 babies are born with a genetic mutation that causes childhood dementia.

Childhood Dementia Causes

This is caused by more than 100 rare genetic conditions. Many of these conditions are associated with genes that affect cell function. These faulty genes cause damage to the brain.

Childhood Dementia Risk Factors

The only risk factor known is carrying a defective gene that is associated with childhood dementia.

Childhood Dementia Symptoms

The symptoms of childhood dementia are similar to adult dementia. They include:

• Anxiety

• Confusion

• Difficulty concentrating

• Fear

• Hyperactivity or other behavioral problems

• Memory loss

• Personality changes

• Seizures

• Sleep problems

• Vision and hearing loss

Childhood Dementia Diagnosis

Biochemical tests can be performed using blood or urine samples. These tests can detect abnormal levels of proteins, sugars, or other substances, or missing enzymes that are associated with genetic conditions. If these tests confirm an abnormality, your health care provider can order a genetic test to look for faulty genes.

Childhood Dementia Treatment

There is no cure or effective treatment for childhood dementia. Right now, health care providers can only focus on easing the symptoms, such as prescribing medication for seizures. But scientists have been working on solutions, and clinical trials are now underway testing some therapies.

This type of dementia is most common in people who have suffered accidents that were serious enough to literally shake the brain back and forth inside the head. Athletes or military veterans who have suffered repeated traumatic brain injuries (TBIs) are also at higher risk for CTE dementia. Other TBIs can be the result of car accidents, falls, or being struck in the head. This impact to the head, such as during a hard tackle in a football game or a battlefield explosion, causes a disruption in the normal functioning of the brain, leading to a decline in cognitive function. Repeated brain injuries can lead to CTE dementia.

CTE dementia is similar to Alzheimer’s disease in that it also involves a buildup of tau proteins in the brain. The difference is that CTE has a different type of pattern of the buildup of tau, around blood vessels. CTE dementia is still being studied and more questions are being answered.

CTE Dementia Causes

Repeated traumatic brain injuries where the brain is shaken inside the head.

CTE Dementia Risk Factors

If you have experienced TBIs in early to mid-life, you are between two and four times more likely to develop CTE dementia. Risk factors also include participating in contact sports, such as boxing and football, and being a military veteran.

CTE Dementia Symptoms

The symptoms of CTE dementia are still being debated by experts in the field, but generally, these symptoms are recognized as common:

• Confusion

• Depression

• Disorganization

• Memory loss

• Personality changes, including erratic behavior, aggression, and suicidal thoughts

• Problems with balance

• Trouble paying attention

CTE Dementia Diagnosis

Unfortunately, a diagnosis of CTE dementia can only be made after death during an autopsy. But if you suspect CTE dementia and have a history of TBIs, a physician familiar with dementia can give you tests to rule out other causes. These tests may include brain imaging, neurological exams, and others.

CTE Dementia Treatment

There are no treatments that have shown success in people with CTE dementia. Some medications can help with symptoms, depending on what the person is experiencing.

It can be very challenging to live with dementia or to support a loved one through a diagnosis of dementia. In most cases, dementia is a progressive disease that will worsen over time. Focusing on the steps you can take to minimize your risk or lessen symptoms can be helpful. Understanding the symptoms, causes, and what to expect as the condition progresses is important for living as well as possible—for both the person experiencing dementia and the caregiver.