Types of Dementia

Dementia is a general term for loss of memory and other mental abilities severe enough to interfere with daily life. It is caused by physical changes in the brain.

Learn more about dementia, what it is, symptoms and treatments

• Alzheimer's disease
• Vascular dementia
• Dementia with Lewy bodies (DLB)
• Mixed dementia
• Parkinson's disease
• Frontotemporal dementia
• Creutzfeldt-Jakob disease
• Normal pressure hydrocephalus
• Huntington's disease
• Wernicke-Korsakoff Syndrome

Alzheimer's disease

Most common type of dementia; accounts for an estimated 60 to 80 percent of cases.

Symptoms: Difficulty remembering recent conversations, names or events is often an early clinical symptom; apathy and depression are also often early symptoms. Later symptoms include impaired communication, poor judgment, disorientation, confusion, behavior changes and difficulty speaking, swallowing and walking.

Revised guidelines for diagnosing Alzheimer’s were published in 2011 recommending that Alzheimer’s be considered a slowly progressive brain disease that begins well before symptoms emerge.

Brain changes: Hallmark abnormalities are deposits of the protein fragment beta-amyloid (plaques) and twisted strands of the protein tau (tangles) as well as evidence of nerve cell damage and death in the brain.

Learn more about Alzheimer's disease.

Vascular dementiaback to top

Previously known as multi-infarct or post-stroke dementia, vascular dementia is less common as a sole cause of dementia than Alzheimer’s, accounting for about 10 percent of dementia cases.

Symptoms: Impaired judgment or ability to make decisions, plan or organize is more likely to be the initial symptom, as opposed to the memory loss often associated with the initial symptoms of Alzheimer's. Occurs from blood vessel blockage or damage leading to infarcts (strokes) or bleeding in the brain. The location, number and size of the brain injuries determine whether dementia will result and how the individual’s thinking and physical functioning will be affected.

Brain changes: Brain imaging can often detect blood vessel problems implicated in vascular dementia. In the past, evidence for vascular dementia was used to exclude a diagnosis of Alzheimer's disease (and vice versa). That practice is no longer considered consistent with pathologic evidence, which shows that the brain changes of several types of dementia can be present simultaneously. When there is clinical evidence of two or more causes of dementia, the individual is considered to have mixed dementia.

Learn more about vascular dementia.

Dementia with Lewy bodies (DLB) back to top

Symptoms: People with dementia with Lewy bodies often have memory loss and thinking problems common in Alzheimer's, but are more likely than people with Alzheimer's to have initial or early symptoms such as sleep disturbances, well-formed visual hallucinations, and slowness, gait imbalance or other parkinsonian movement features.

Brain changes: Lewy bodies are abnormal aggregations (or clumps) of the protein alpha-synuclein. When they develop in a part of the brain called the cortex, dementia can result. Alpha-synuclein also aggregates in the brains of people with Parkinson's disease, but the aggregates may appear in a pattern that is different from dementia with Lewy bodies.

The brain changes of dementia with Lewy bodies alone can cause dementia, or they can be present at the same time as the brain changes of Alzheimer's disease and/or vascular dementia, with each abnormality contributing to the development of dementia. When this happens, the individual is said to have mixed dementia.

Learn more about dementia with Lewy bodies.

Mixed dementiaback to top

In mixed dementia abnormalities linked to more than one cause of dementia occur simultaneously in the brain. Recent studies suggest that mixed dementia is more common than previously recognized, with about half of older people with dementia having evidence of more than one cause of dementia. Recent studies also show that the likelihood of having mixed dementia increases with age and is highest in the oldest-old (people age 85 or older).

Brain changes: Characterized by the hallmark abnormalities of more than one cause of dementia — most commonly Alzheimer’s combined with vascular dementia, followed by Alzheimer’s with dementia with Lewy bodies, and Alzheimer’s with vascular dementia and dementia with Lewy bodies. Vascular dementia with dementia with Lewy bodies is much less common.

Learn more about mixed dementia.

Parkinson's diseaseback to top

As Parkinson's disease progresses, it often results in a progressive dementia similar to dementia with Lewy bodies or Alzheimer's.

Symptoms: Problems with movement (slowness, rigidity, tremor and changes in gait) are common symptoms of the disease.

Brain changes: Alpha-synuclein clumps are likely to begin in an area deep in the brain called the substantia nigra. These clumps are thought to cause degeneration of the nerve cells that produce dopamine.

Learn more about Parkinson's disease.

Frontotemporal dementiaback to top

Includes dementias such as behavioral-variant frontotemporal lobar degeneration (FTLD),
primary progressive aphasia, Pick's disease, corticobasal degeneration and progressive supranuclear palsy.

Symptoms: Typical symptoms include changes in personality and behavior and difficulty with language. Nerve cells in the front and side regions of the brain are especially affected.

Brain changes: No distinguishing microscopic abnormality is linked to all cases. The symptoms of FTLD may occur in those age 65 years and older, similar to Alzheimer’s, but most people with FTLD develop symptoms at a younger age. About 60 percent of people with FTLD are ages 45 to 60. FTLD accounts for about 10 percent of dementia cases.

Learn more about frontotemporal dementia.

Creutzfeldt-Jakob diseaseback to top

CJD is the most common human form of a group of rare, fatal brain disorders affecting people and certain other mammals. A specific form called variant Creutzfeldt-Jakob disease is believed to be caused by consumption of products from cattle affected by mad cow disease.

Symptoms: Rapidly fatal disorder that impairs memory and coordination and causes behavior changes.

Brain changes: Results from misfolded prion protein that causes a "domino effect" in which prion protein throughout the brain misfolds and thus malfunctions.

Learn more about Creutzfeldt-Jakob disease.

Normal pressure hydrocephalus back to top

Symptoms: Symptoms include difficulty walking, memory loss and inability to control urination.

Brain changes: Caused by the buildup of fluid in the brain. Can sometimes be corrected with surgical installation of a shunt in the brain to drain excess fluid.

Learn more about normal pressure hydrocephalus.

Huntington's Disease back to top

Huntington’s disease is a progressive brain disorder caused by a single defective gene on chromosome 4.

Symptoms: Include abnormal involuntary movements, a severe decline in thinking and reasoning skills, and irritability, depression and other mood changes.

Brain changes: The gene defect causes abnormalities in a brain protein that, over time, lead to worsening symptoms.

Learn more about Huntington’s disease.

Wernicke-Korsakoff Syndromeback to top

Korsakoff syndrome is a chronic memory disorder caused by severe deficiency of thiamine (vitamin B-1). The most common cause is alcohol misuse.

Symptoms: Memory problems may be strikingly severe while other thinking and social skills seem relatively unaffected.

Brain changes: Thiamine helps brain cells produce energy from sugar. When thiamine levels fall too low, brain cells cannot generate enough energy to function properly.

Learn more about Wernicke-Korsakoff syndrome.