Types of Dementias

Alzheimer’s

Alzheimer’s, a degenerative brain disease, is the most common form of dementia. Dementia itself is not a specific disease. The word is a general term for loss of memory and other mental abilities that are significant enough to interfere with everyday life. While Alzheimer’s represents 60 to 80% of diagnosed cases, there are many types of dementia–and all result from physical changes in the brain.

Dementia with Lewy Bodies

Dementia with Lewy bodies (DLB) involves abnormal microscopic deposits called Lewy bodies that damage brain cells over time. This type of progressive dementia affects thinking, reasoning, and independent function. Lewy bodies appear in other brain disorders, including Alzheimer’s and Parkinson’s disease dementia, although memory loss generally occurs later in DLB.

Vascular Dementia

Vascular dementia sometimes takes place after a stroke that has blocked blood vessels. But in all cases, blocked or reduced blood flow to the brain deprives brain cells of vital oxygen and nutrients. This leads to a decline in thinking skills. Vascular brain changes often coexist with changes linked to Alzheimer’s, DLB, and other dementia forms. Several studies have found that vascular changes and other brain abnormalities may interact in ways that increase the likelihood of dementia diagnosis. But because these changes range broadly from mild to severe, some professionals choose to this condition vascular cognitive impairment (VCI).

Parkinson’s Disease

Parkinson’s disease dementia is an impairment in thinking and reasoning that eventually affects many people with Parkinson’s disease. The brain changes caused by Parkinson’s disease begin in a region that plays a key role in movement. As these brain changes gradually spread, they often begin to affect mental functions like memory, judgment, and attention span. The key brain changes linked to Parkinson’s disease and Parkinson’s disease dementia are abnormal microscopic deposits composed chiefly of Lewy bodies, which are also found in DLB and other brain disorders.

With more than one million Americans living with Parkinson’s and the disease affecting nearly 2% of those over the age 65, researchers estimate that 50 to 80% of them will eventually show signs of Parkinson’s disease dementia over a 10-year period. Along with memory and judgment changes, this type of dementia often results in muffled speech, visual hallucinations, depression, delusion, sleep disturbances, irritability, and anxiety.

Posterior Cortical Atrophy

Posterior cortical atrophy (PCA) refers to gradual and progressive degeneration of the brain’s cortex and posterior. But researchers do not yet know whether this a unique disease or a variant form of Alzheimer’s. Some PCA-affected brains have amyloid plaques and neurofibrillary tangles, which are similar to what happens in Alzheimer’s. Yet other PCA patients exhibit brain changes similar to DLB or CJD, which is Creutzfeldt-Jakob disease. PCA onset usually occurs in a patient’s 50s or 60s, 15 years before Alzheimer’s symptoms begin to show.

Creutzfeldt-Jakob Disease

Creutzfeldt-Jakob disease (CJD) is the most common human form of a group of rare, fatal brain disorders known as prion diseases. CJD occurs when prion protein begins folding into an abnormal three-dimensional shape. This gradually triggers prion protein in the brain to fold into the same abnormal shape. CJD causes a type of dementia that worsens unusually fast.

Frontotemporal Dementia

Frontotemporal dementia (FTD), or frontotemporal degenerations, comes from progressive nerve cell loss in the brain’s frontal and temporal lobes. This affects nerve cells and causes language disturbances, changes in muscle or motor functions, and affects the individual’s behavior and personality.