What is a Dementia?

Alzheimer's disease, Other Types of Dementia, and How to Tell the Difference

Article Summary

• There are multiple types of dementia; Alzheimer's disease is the most common form of dementia.


• Dementia is a term which refers to a range of brain conditions that are marked by cognitive impairment. Conditions include forgetfulness, cognitive decline, agitation, and many other symptoms.


• Different types of dementia can be caused by different factors and treated in different ways.

• In the article we discuss the different types of dementia, how to differentiate them and their treatment options.


Dementia is a general term which refers to the loss of mental abilities, primarily memory and cognition. There are multiple types of dementia with Alzheimer’s disease being the most common type. Alzheimer's disease accounts for about 70 percent of all dementia cases. Below we take a closer look at the other types of dementia and the symptoms which differentiate them. It’s important to understand which type of dementia an individual is affected by because they are treated in different ways.


Diseases are listed in order of how often they occur, starting with the most common.


Alzheimer’s Disease

Responsible for 70% of all dementia.



Alzheimer’s disease is the most common form of dementia. Alzheimer’s disease is a result of excess protein fragments- plaques and tangles- building up in the brain. These build ups slowly damage neurons and the brain’s ability to function. Alzheimer’s disease is a slowly progressive brain disease that begins years prior to the appearance of symptoms.


Differentiating Symptoms:

Symptoms of Alzheimer’s disease include difficulty recalling past and recent events, confusion, depression, apathy, and difficulty communicating.


Vascular Dementia

Responsible for 10% of all dementia. 



Vascular dementia is when inadequate blood flow causes damage to the brain. Vascular dementia most commonly occurs after traumatic brain injuries or blood flow blockages to the brain, especially after a stroke.


Differentiating Symptoms:

Vascular dementia is distinguished from Alzheimer’s disease as initial symptoms often include difficulty with cognition, as opposed to memory loss. Difficulty with cognition is often seen as trouble planning, organizing, or making decisions. A major indicator of a vascular dementia is sudden and dramatic loss in brain functioning after a stroke or injury. Vascular dementia can often be detected by brain scans.


Parkinson’s Disease

Responsible for 5% of all dementia.



Parkinson’s is caused by abnormal microscopic deposits in the brain composed mainly of a protein called alpha-synuclein. The normal functioning of alpha-synuclein is not yet known.

Parkinson’s disease begins damaging the brain in an area of the brain responsible for movement, a factor explaining the tremors commonly associated with Parkinson’s disease.


Differentiating Factors:

The most distinguishing identifier of Parkinson’s disease is that physical symptoms appear prior to mental symptoms. Physical symptoms, such as tremors and difficulty with hand coordination, will appear before mental symptoms like memory or cognition loss. An example of these tremors are shown in the following video:



More Information:



Dementia with Lewy Bodies

Responsible for for under 5% of all dementia.



Dementia with Lewy bodies is caused by abnormal deposits of the protein alpha-synuclein. Lewy bodies are the term given to the deposits of alpha-synuclein. The main symptoms of dementia with Lewy Bodies are similar to Alzheimer’s, including memory loss and difficulty with cognition.


Differentiating Factors:

Dementia with Lewy bodies is different from other dementias in that individuals are more likely to suffer from sleep disturbances, visual hallucinations, and muscle rigidity. It’s possibly to detect dementia with Lewy bodies by brain scans.


Further Information:



Normal Pressure Hydrocephalus

Responsible for less than 5% of all dementia.



Normal pressure hydrocephalus (NPH) occurs when excessive brain and spinal fluid accumulate in the brain. The buildup of fluid causes a significant increase in pressure in the brain, damaging neurological tissue and impairing mental ability.


Differentiating Symptoms:

The main causes of NPH are unknown, however major causes include brain hemorrhages and brain infections. The distinguishing symptoms of normal pressure hydrocephalus include loss of bladder control and a type of difficulty walking described as “magnetic feet.” While walking it appears as if the individual’s feet are stuck to the ground. The excessive fluid characteristic of normal pressure hydrocephalus can be detected with an MRI scan.

Further Information:


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