What’s the Life Expectancy for Someone With Dementia?

Senior with dementia or Alzheimer's is comforted by caring female doctor

Dementia is a type of disease that is thoroughly misunderstood. The widely known view of dementia is that it means someone has Alzheimer’s and is going to forget their family and friends. While this is one true part of what happens in many families affected by dementia, there is a whole medical sphere dedicated to understanding and treating it. 

The fact is, dementia is a fatal disease. Whether it slowly progresses over time or seems to consume a person all too soon, all types of dementia impact the end-of-life process and eventual death. It’s important to learn about what a dementia life expectancy can mean.

How Does Dementia Affect Life Expectancy? 

Many types of dementia cause deterioration to the brain, which means a person’s life expectancy becomes significantly shortened. Other types affect the physical body and motor function, which can lead to a lower quality of life and individual autonomy at an earlier age. 

Some people receive a dementia diagnosis and can still live fairly healthy and functionally for decades to come. Others get diagnosed too late and quickly experience major cognitive decline that leads to early death. 

Dementia changes how a person’s brain functions and processes information. People with dementia develop memory problems, personality changes, impairment to their movement abilities, and a decline in their cognitive, emotional, and physical health. All these things can dramatically affect life expectancy, especially because there is no cure for dementia. 

memory loss due to dementia
Dementia goes through various stages depending on the area of the brain that’s affected.

Symptoms of Dementia 

The signs and symptoms of dementia vary greatly based on what type of dementia a person has. Remember, there are many kinds of dementia that come with their unique challenges and prognoses. 

In general, though, there are overarching symptoms that come with most types. The stages can be seen throughout almost all forms of dementia. In the medical realm, these are referred to as Early Stage Dementia, Middle Stage Dementia, and Late Stage Dementia. 

Here are some of the common symptoms that are seen in each dementia stage.

Early Stage Dementia (Mild Dementia)

  • Memory trouble
  • Forgetfulness, brain fog
  • Mild cognitive impairment 
  • Slight changes in mood or personality
  • Increased inability to focus and concentrate
  • Experiencing “senior moments”, like confusing loved ones’ name or events
  • Losing track of time
  • Decrease in spacial awareness 
  • Trouble finding the right words during conversations
  • Delay in performing basic daily activities, like paying bills, organizing the pantry, or showing up to appointments on time

Middle Stage Dementia

  • Forgetting personal information, like your phone number or a close relative’s address
  • Jumbled long-term or short-term memories (timeline of events become hard to recall)
  • Unexplainable mood swings, irritability, or aggression
  • Forgetting the date, year, or month 
  • Confusing what season one is currently in (wearing winter clothes in mid-summer, etc.)
  • Disturbed sleep (insomnia or excessive sleeping)
  • Repetitive or compulsive actions, such as touching the face or cleaning incessantly 
  • Behavioral changes, paranoia, delusions 
  • Physical impairments like difficulty holding one’s bladder 
  • Wandering aimlessly or easily getting lost in one’s community 

Late Stage Dementia

  • Becoming unfamiliar with loved ones; forgetting family and friends
  • Inability to feed oneself or use the bathroom on their own
  • Drastic behavioral changes
  • Difficulty swallowing food or water 
  • Becoming disillusioned or disconnected from reality
  • Loss of bodily control (walking, using the bathroom, moving, self-care)
  • Communication struggles
  • Loss of personal identity 

How is Dementia Caused? 

As of now, there is no distinct known cause of dementia. Science is always working to research what factors contribute to this deadly disease. It is an extremely complex disorder to fully know. Because of this, it’s also incredibly hard to effectively treat. 

While there are no known causes of all the different types of dementia, there are some theories that it has to do with genetics and lifestyle factors. Right now, the only claim at trying to prevent dementia has to do with lifestyle.

Some of the things that can contribute to dementia development include:

  • Severe brain injury
  • Damage to brain cells
  • Preexisting medical conditions that decrease oxygen to the brain
  • Genetics and personal health
  • Unhealthy lifestyle 

Common ways to prevent dementia that are known include leading a healthy life. Eating clean, practicing regular exercise, learning how to effectively manage stress, and engaging in brain-stimulating activities and hobbies might be able to help. All these things are what help keep the brain healthy, active, and capable of repair. 

Types of Dementia: Life Expectancy for Each

Each type of dementia has its own set of symptoms, outcomes, and timeline that affects life expectancy. Additionally, every person who is diagnosed with dementia will have factors that affect their experience with dementia. No two dementia cases are perfectly identical, but they can be similar.

Alzheimer’s Disease 

The most frequent diagnosis and cause of dementia, Alzheimer’s disease has shown major patterns in dementia life expectancy. This is because it comes with brain damage associated with a disconnect in neurons (brain never cells). 

Some studies have shown that this disease is also associated with a buildup of abnormal fibers and proteins in the brain, which can contribute to memory loss. Eventually, the brain physically deteriorates over time. This is what leads to the eventual cause of death among late-stage dementia. 

Symptoms Specific to Alzheimer’s

  • Decline in cognition 
  • Memory loss
  • A decline in thinking, reasoning, and expression 
  • Impaired judgment when making decisions 
  • Personality and behavior changes 
  • Social withdrawal 
  • Confusion 
  • Progressive decline overall 

The life expectancy of someone with Alzheimer’s disease is typically 10 years or so after they have been diagnosed. Some people with Alzheimer’s live decades after they onset dementia symptoms begin. Others only live 6-8 years past their initial mild symptoms.

Lewy Body Dementia 

Another common type of dementia is Lewy body dementia (LBD), or “dementia with Lewy bodies”. This is another type of dementia that increasingly gets worse and worse over time until inevitable death. 

“Lewy bodies” are types of proteins that grow and build up in the brain. An abnormal amount of lew bodies can begin to grow and interrupt brain nerve cells. When this happens, it can drastically affect thinking and physical motor ability. 

LBD is slightly different than Alzheimer’s because it is generally related to more severe physical symptoms and changes to how the brain processes information. There are two types of Lewy body dementia:

1. Dementia with Lewy bodies

2. Parkinson’s disease dementia 

Symptoms of LBD:

  • Muscle aches or stiffness
  • Tremors or shakes
  • Major changes to behavior 
  • Struggles with balance and movement 
  • Memory issues
  • Disorganized thoughts, speech, and emotions
  • Decline in alertness 
  • Hallucinations 
  • The body struggling to regulate blood pressure, heart rate, and digestion 
  • Damage to the automatic nervous system

Lewy body dementia life expectancies usually range from 4 – 8 years after diagnosis. However, some people have lived roughly 20 years after being diagnosed with LBD. Symptoms usually start mild and slow, then progress over a number of years. 

Vascular Dementia 

Vascular dementia is a type of dementia that is caused by issues with the vascular system (anything related to blood and oxygen transfer). This dementia is a result of changes or blockages in the body’s blood supply to the brain. 

Most often with vascular dementia, it occurs after a stroke or serious injury. When the blood supply is dangerously cut off from the brain, brain cells can die and parts of the brain can become permanently damaged. People can start to show symptoms right after a stroke (or numerous strokes), or signs can appear years later.

Symptoms of Vascular Dementia

  • Stroke-like symptoms 
  • Paralysis, weakness, or numbness either in one part or several parts of the body
  • Difficulty walking or moving
  • Gaps in reasoning or logical thinking
  • Changes in personality and mood
  • More intense emotions and mood swings than usual
  • Unable to focus or pay attention to important tasks

Typically, the life expectancy for someone with vascular dementia is short. On average, people live about 5 years after being diagnosed. They can sometimes live longer, but it’s unlikely that their lifespan will include capabilities before middle-stage dementia symptoms. They will usually require constant care and supervision. 

Frontotemporal Dementia 

Frontotemporal dementia (FTD) can appear in people younger than 50, which is a bit different compare to Alzheimer’s or Lewy body dementia. Most of the time, Frontotemporal dementia is diagnosed in people around their 40s. 

This is a more rare type of dementia and its main characteristics affect language and behavior. It can be a scary and confusing disorder when not diagnosed on time, or when improperly diagnosed. 

Symtps of Frontotemporal Dementia 

  • Language and speech problems 
  • Loss of social awareness (acting out or being inappropriate in groups)
  • Major personality changes 
  • Mood changes (depression, panic, aggression)
  • Obsessive or compulsive actions (drug or alcohol use, repetitive actions)
  • Loss of motivation for life 
  • Repetitive communication or incoherent expression 
  • Dangerous risk-taking behavior or outlandish ideas
  • Fragments in empathy or compassion; malicious actions
  • Becoming impulsive 
  • Signs of mental illness

The frontotemporal lobe dementia life expectancy is, on average, 6 – 8 years after being diagnosed. They can sometimes live another decade, but require 24/7 supervision and health care. 

Is There Treatment for Different Types of Dementia?

There is currently no cure or official treatment for any type of dementia. As mentioned before, it is a fatal disease that progresses over time. The only “treatment” for it is to track and manage the symptoms that come with each phase. 

Providing comfort, safety, support, and medical care throughout the three stages is often the only thing that can be done during the person’s new dementia life expectancy. 

How to Know Someone’s Dementia Life Expectancy 

Life and death are constant mysteries that no human will likely ever fully figure out. Of course, there is no way to officially know how long someone will continue to live, even if they have a sure diagnosis of something. 

But by observing scientific patterns of the various types of dementia, you can get a general range of time for how most other people with that disease have lived. 

With modern technology, there is even data prediction software that can account for relevant symptoms and predict average life expectancy. This type of technology uses dementia research and algorithms to give an estimated prediction of how long a person might live. It takes into account their lifestyle, age, history, diagnosis, and level of care available. 

You should never rely on this type of estimate, but it’s simply a guide. If you or a loved one has dementia, focus on getting the right types of care they will need moving forward. Enjoy the time you have left with them. Find the support you need as a family member during this hard diagnosis. 

retired couple holding hands and looking at each other
Dementia can be overwhelming for the families of affected people and support is needed from the healthcare system.

Caring for Someone With a Dementia Diagnosis 

Finding out someone you care about has dementia can be a piece of life-shattering news. So many questions, fears, and sorrows come with the realization that a friend or family member will soon be rapidly declining in their last years of life. 

There are ways to find peace, support, and adequate care for your loved one with dementia. It might take some time at first, but developing a care plan can make everyone’s life easier in the next phase. 

Make a Plan

The first step to caring for someone with dementia is to make a plan. Learn all you can about their type of dementia. 

As time progresses, research hospitals, nursing homes, and dementia care advocates, so you have a set plan of action when your loved one starts to reach late-stage dementia. In the later stages, dementia patients require ongoing, constant supervision and medical aid. 

Health Care Aid

Managing and monitoring someone with dementia can be expensive when it comes to health care. Look into what your insurance provider will cover, seek government aid, and any local resources available to you and your family. 

Remember that you don’t have to do this alone. It takes a community that loves and supports each other to get through the challenges that come with dementia and death.

At Home Caregivers

If your loved one is entering the middle to late stages of their disease, you must look into home caregivers. These professionals can make the patient comfortable, help them with daily life, and be there if any emergencies occur. 

Support from Loved Ones and Community

There are support groups for family and friends of individuals with dementia. It’s a life-harrowing process, and the sad fact is that dementia loses your loved one slowly. Finding a safe mental and emotional outlet to process, share, and grieve the little losses can keep you sane as you continue to care for them in their last years.

What to Do During End of Life Dementia

Once the inevitable end-of-life process begins and your loved one with dementia can no longer function on their own, there are a few steps required on behalf of family and friends. Here are the general steps that occur during the final stages of dementia.


If the person’s dementia has been happening for years or even decades, you’ve likely had time to reach an understanding of what will happen. If not, learn more about dementia while you can, so you can offer the support needed. 

Remember to not take any outrageous or negative behaviors personally, as it’s not the patient’s fault they are acting this way. They might say offensive things, behave aggressively, or completely forget who you are. It’s easy to become angry and hurt by witnessing this tragic loss of their personality. But it’s not the person who is doing these things… it’s an effect of their brain’s decline. 

Family Support 

Bringing the family together and helping each other out is a crucial aspect of late-stage dementia. Although you might not be able to emotionally relate to your loved one anymore as they near death, you can lean on fellow loved ones to say goodbye and find peace in the situation. 

Comfort Your Loved One

The only thing left to do is now make sure your loved one is comfortable, safe, and has the care they need during their last moments. Caregivers can make sure they live in a sanitary environment, have the nourishment they need, and ensure they won’t cause any harm to themselves or others.


Finally, acceptance of the person’s life and death helps bring peace to the loss. It takes a long time to grieve a loved one after slowly losing them to dementia. But starting to accept the loss for what it is can help you move forward with precious memories and time you did share with them, whether during their best or worst.

If you need guidance finding care or support for someone with dementia, reach out to a professional care facility today. Help is available and your family needs all the resources they can get. 

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