It’s not uncommon to hear the terms “dementia” and “Alzheimer’s disease” used interchangeably, but the two are quite different. Dementia is a general term for a severe loss of memory and other cognitive capacities caused by physical changes in the brain. Alzheimer’s disease is just one of several types of dementia.
In keeping with Alzheimer’s Awareness Month, we’ve provided snapshots of three of the most common dementia types below. Note that while some cognitive impairment is normal with advancing age, in the case of dementia, symptoms are usually severe enough to interfere with everyday activities.
Accounting for 60 to 80 percent of cases, Alzheimer’s disease is the most common type of dementia. It arises when plaques and bundles of proteins build up between nerve cells in the brain, causing atrophy and, ultimately, brain cell death.
While Alzheimer’s begins well before the first symptoms register, the earliest detectable signs include trouble with memory, such as struggling to remember names and conversations, apathy, and depression. As the disease progresses, more severe symptoms—including impaired communication, poor judgment, and disorientation—emerge.
Vascular dementia accounts for roughly 10 percent of dementia cases. Befitting its name, vascular dementia is associated with damaged and blocked blood vessels in the brain. This leads to decreased blood flow to areas of the brain and, as a result, dead tissue. The severity of a case will depend on the location, number, and size of the damage or blockages.
Unlike Alzheimer’s, where memory loss typically emerges first, with vascular dementia, the earliest symptoms tend to include impaired judgment or ability to make decisions, plan, or organize.
Dementia with Lewy Bodies (DLB)
One of the most common types of dementia after Alzheimer’s and vascular dementia, DLB results when abnormal clumps of protein (called Lewy bodies) develop around the cortex. Like Alzheimer’s patients, people with DLB often experience memory loss and cognitive issues. However, they are more likely to suffer initial symptoms such as sleep disturbances, visual hallucinations, and imbalanced gait, similar to those with Parkinson’s.
In Brief: Less Common Types of Dementia
- Mixed dementia arises when two or three forms of dementia occur at once.
- Motor difficulties are one of the signature symptoms of Parkinson’s disease, which otherwise manifests similarly to DLB.
- There are several subtypes of frontotemporal dementia, which leads to language difficulties and changes in personality and behavior.
- Creutzfeldt-Jakob disease, a.k.a. “mad cow disease,” is a rapidly fatal disorder that triggers changes in behavior, memory, and coordination.
- Caused by excess fluid in the brain, normal pressure hydrocephalus results in impaired memory, difficulty walking, and incontinence. It can sometimes be treated with the draining of fluid.
- Huntington's disease is a progressive brain disorder caused by a chromosomal defect. Its symptoms include abnormal involuntary movements, a severe decline in thinking, and mood disturbances.
- Commonly associated with alcohol misuse, Wernicke-Korsakoff Syndrome is a chronic memory disorder.