Dementia is the chronic loss of cognitive functions that affect one’s ability to think, remember and reason. Dementia ranges in severity and can progress to such an extent that it interferes with daily activities such as bathing, keeping house and paying bills. There are hundreds of conditions that can be associated with dementia. The five most common forms of dementia due to neurodegenerative conditions (loss of brain cells) are mixed dementia, Alzheimer’s Disease, Vascular Dementia, Lewy Body Disease, and Fronto-temporal dementia (which includes multiple conditions such as Primary Progressive Aphasia).

Information about dementia in general can be found at: https://www.nia.nih.gov/health/what-is-dementia

Mixed Dementia

Mixed dementia is when more than one type of condition that can cause dementia is present.  Large brain autopsy (examinations of brain tissue after death under a microscope) show that more than half of individuals with dementia have Alzheimer’s disease brain changes as well as the brain changes of one or more other causes of dementia.

Alzheimer’s Disease

Alzheimer’s is a slowly progressive brain disease. It begins many years before symptoms emerge.  Early symptoms can include difficulty remembering recent conversations, names or events along with mood changes such as depression. Later symptoms include impaired communication, poor judgment, behavioral changes and, ultimately, difficulty speaking, swallowing and walking. The hallmark brain tissue changes of Alzheimer’s disease are the accumulation of the protein beta-amyloid (plaques) outside brain cells called neurons and twisted strands of the protein tau (tangles) inside neurons in the brain. These changes are accompanied by the damage to brain tissue and death of neurons.

Alzheimer’s Disease Fact Sheet – From the National Institute on Aging

Vascular Dementia

Vascular dementia occurs most commonly from blood vessel blockage.  Blood vessel blockage occurs with stroke, or damage leading to areas of dead tissue or bleeding in the brain. The location, number and size of the brain injuries determine whether dementia will result. Slowed thoughts, impaired ability to make decisions may be the initial symptoms, but memory may also be affected.

General Information – From the Alzheimer’s Association

Vascular Dementia – From the American Stroke Association

Lewy Body Dementia

Lewy bodies are abnormal aggregations (or clumps) of the protein alpha-synuclein in neurons. When Lewy Bodies develop throughout the brain, this is called dementia with Lewy bodies or DLB. People with DLB have some of the symptoms common in Alzheimer’s.  However, they are more likely to have initial or early symptoms of sleep disturbances and well-formed visual hallucinations. These symptoms may differ by the hour. Problems with motor function (similar to Parkinson’s disease) are also common. Memory loss often occurs at some point in the disease.


Lewy Body – From the Alzheimer’s Association

Lewy Body Booklet – From the National Institute on Aging

Understanding Lewy Body – From the National Institute on Aging

Lewy Body Dementia Association


A Caregiver’s Guide to Lewy Body Dementia by Helen Buell Whitworth and James Whitworth

Frontotemporal Dementia (FTLD)

FTLD includes dementias such as behavioral-variant FTLD, primary progressive aphasia, Pick’s disease, corticobasal degeneration and progressive supranuclear palsy. Nerve cells in the front (frontal lobe) and side regions (temporal lobes) of the brain are especially affected. An abnormal protein is present (usually tau protein or the transactive response DNA-binding protein, TDP-43). The symptoms of FTLD may occur in those age 65 years and older, similar to Alzheimer’s.  However, most people with FTLD develop symptoms at a younger age (between 45 and 60). Typical early symptoms include marked changes in personality and behavior and/or difficulty with producing or comprehending language. Memory is typically spared in the early stages of disease.

General Information – From the Alzheimer’s Association

General information – From the National Institute on Aging

The Association of Frontotemporal Degeneration

Primary Progressive Aphasia

Symptoms and Causes of PPA – from Northwestern

Primary Progressive Aphasia – National Aphasia Association

Primary Progressive Aphasia – From the National Institute on Health

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