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Lewy Body Dementia vs Alzheimer's

Updated: Aug 8, 2023

Lewy body dementia and Alzheimer’s disease are the most common types of dementia prevalent in the world today. LBD occurs in over one million people in the United States as the second most common type of dementia, while Alzheimer’s disease is the most common by far, accounting for 5.8 million cases in the US.

People with both conditions experience changes in the brain that cause physical, cognitive, and behavioral symptoms. They have several similarities as both are forms of dementia, but there are also clear differences between them.

What is Alzheimer’s?

Alzheimer’s is a progressive neurological disease that causes the brain to shrink and brain cells to die. It begins with mild memory loss and derails into loss of cognitive, behavioral, and social functions like the ability to converse and respond to your environment. It is characterized by amyloid plaques and neurofibrillary tangles in the brain. One of the key symptoms of Alzheimer’s is memory loss and other symptoms of Alzheimer’s are in the image below.

What is LBD?

Lewy body dementia is a condition where abnormal protein deposits called alpha-synuclein are found in the brain. The deposits are called Lewy bodies and affect the brain’s chemical make-up, causing changes that lead to problems in thinking, behavior, mood, and movement. It is a progressive disease with a slow onset of symptoms that worsen over time. The development of signs and changes vary significantly from one patient to another, depending on their overall health, age, and symptoms.

The Link Between the Two Diseases

As per the Alzheimer’s Association, Alzheimer’s disease and LBD can co-occur. Lewy bodies can be found in people with Alzheimer’s, and plaques and tangles, which are the key markers of Alzheimer’s, can occur in people with Lewy body disease.

Now that we’ve established what either of the diseases is, let’s see how they differ across key categories of causes, symptoms, treatment, life expectancy, risk factors, and outlook.

It must be noted, however, that research hasn’t confirmed what exactly triggers the changes in the brain in either case.

Lewy Body Dementia


There is no identified cause for the onset of LBD.


Various symptoms of LBD include:Alteration in thinking and reasoning patterns.Varying confusion and alertness in day-to-day life.Visual hallucinations.Experiencing delusions.Disrupted sleep, and/or poor quality of sleep.Significant memory loss – but not as prominent as Alzheimer’s. Slowed movements, changes in mobility. Difficulty in understanding and interpreting visual information and cues.

Age of onset

The disease usually occurs between 50 and 85 years of age.


Treatment is holistic, including medication, changes in lifestyle, and cognitive and behavioral therapy to treat symptoms and slow down the progression of the disease.

Life expectancy

On average, people live up to 5-8 years after diagnosis but can also live as long as 20 years.

Risk factors

Old age, REM sleep disorder, and Parkinson’s disease.


The disease is incurable. It can only be managed. Treatment can help mitigate the symptoms, which may vary from day to day.



The causes of Alzheimer’s disease are not clear, but they include a combination of lifestyle, environmental and genetic factors. At a basic level, the brain proteins stop functioning normally, which upsets the brain cells and triggers toxic events.


There are various symptoms of Alzheimer’s:Memory loss is the key symptom. The early signs include difficulty in remembering recent events, conversations, and information. Repeating statements and questions over and over.Getting lost in familiar places.Forgetting the names of everyday objects.Difficulty in thinking and reasoning – multitasking and managing finances, and balancing checkbooks is tough.Declining ability to make reasonable decisions and judgments in everyday situations.Planning and performing familiar tasks is difficult. Changes in personality and behavior, including depression, apathy, loss of inhibitions, mood swings, withdrawal, and distrust.

Age of onset

The disease often occurs during the mid-sixties, but sometimes it can start earlier.


The disease is incurable; it can only be managed. Treatment can help mitigate the symptoms, which may vary day to day.

Life expectancy

People live for an average of 4-8 years post-diagnosis, but some can live up to 20 years.

Risk factors

Age, Down Syndrome, family history, genetics, mild cognitive impairment, head trauma, air pollution, sex, excessive alcohol consumption, poor sleep patterns, lifestyle, and heart health.


The disease is incurable. The symptoms worsen over time. Medication is given to help manage the symptoms and slow down the progression of the disease.

Comparison of Common Factors between L

BD and Alzheimers

The diseases can impact similar functions and aspects of the human body – but in different ways.


In LBD, memory, and symptoms can vary significantly. For example, a person may be able to recognize you on some days, and on some days, they will fail to do so.

In Alzheimer’s, however, while cognition can vary to some extent, the person’s cognition – his/her ability to think and use their memory – experiences a gradual decline over time. Unlike LBD, the symptoms do not change day to day.

Disease progression

A study on survival and mortality differences between dementia with Lewy bodies vs. Alzheimer’s disease conducted by James E Galvin found that the median survival time for people in the study with LBD was 78 years old. Survival after the onset of the disease was 7.3 years.

Regarding Alzheimer’s, the median survival time for patients in the study was 84.6 years, and the survival rate after diagnosis was 8.4 years.

Researchers suggest that the difference in disease progression can be attributed to a higher number of falls leading to injuries and consequent hospitalization in people with LBD.

REM sleep behavior disorder

LBD patients sometimes experience REM sleep behavior disorder. The condition involves a dysfunction that makes them physically act out situations in their dreams. Stu

dies suggest that REM sleep behavior disorder can be an early symptom of LBD.

On the other hand, while some type of sleep disturbance may occur in people with Alzheimer’s, REM sleep behavior disorder is not typically associated with it.

Visual hallucinations

Visual hallucinations refer to people seeing things that aren’t there. These are common amongst people with LBD and typically occur earlier in the progression of the disease.

In Alzheimer’s, hallucinations do occur, but they are not as frequent or prevalent as in people with LBD. They also occur in the later stage of the disease as opposed to its onset.

Facial expressions

People with LBD tend to have a face with the ‘flat affect’, where their faces show

little to no emotion. The symptom is often present early in the disease. It often overlaps with Parkinson’s disease, a progressive nervous system disorder impacting movement.

In Alzheimer’s, facial expressions only deteriorate until the middle to later stages of the disease. They decrease with time.

If you think your or your loved one has symptoms similar to LBD or Alzheimers, visit NeuroX. NeuroX provides affordable psychiatric and neurology care at your doorstep and can provide you with the medical and emotional support you require. Head to NeuroX right now to get started and get online consultations from a board-certified neurologist of your choice within 24-48 hours.

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