Understanding Dementia


Dementia is a general term which refers to a range of brain conditions that are marked by cognitive impairment. Conditions generally include forgetfulness and cognitive decline.

There are several different types of dementia. These types have different causes, different symptoms, and different treatments. Below we discuss the five most common types of dementia, together they make up about 95% of all cases of dementia. Alzheimer’s disease is the most common and accounts for about 70% of all dementia cases.

Alzheimer’s Disease

Responsible for 70% of all dementia.



Alzheimer’s disease is the most common form of dementia. Alzheimer’s disease is believed to be caused by harmful 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.

Learn More: What is Alzheimer's Disease?


Differentiating Symptoms

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

Learn More: Normal Memory Loss or Alzheimer's Disease?


Vascular Dementia

Responsible for 10% of all dementia. 



Vascular dementia occurs 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.

Learn More: Mayo Clinic - Vascular Dementia


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 which explains 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:

Tremor Disorder or Parkinson's?


Learn More: Parkinson's Foundation


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 dementia 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.


Learn More: Lewy Body Dementia Association

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.

Learn More: Hydrocephalus Association


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