In February 2023 the 4 main types of dementia, the family of actor Bruce Willis made an announcement about his health. The previous year, Willis was diagnosed with aphasia, a disorder that prevents a person from speaking or understanding speech. As his condition worsened, doctors found Bruce Willis has frontotemporal dementia.
Frontotemporal dementia is one of the four main types of dementia. About 50 million people in the world are living with dementiaand epidemiologists expect that number to triple by 2050. About two-thirds of these projected cases are likely to be in middle- and lower-income countries.
Advances in medical technology now allow doctors to use biomarker testing and brain imaging to identify the type of dementia a person has and how far the disease has progressed. Although there is currently no cure for dementia, having a clear diagnosis can help patients and their families prepare for the future. With over 100 different types of dementiathese are the four most common.
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1. Alzheimer’s disease/The 4 main types of dementia
Alzheimer’s disease is the most common form of dementia, which accounts for between 60 and 80 percent of dementia cases. It is a degenerative disease of the brain; people can live for years with no or mild symptoms.
Early symptoms of Alzheimer’s include memory loss, such as not remembering a recent conversation. Symptoms progress in severity and include confusion, disorientation, poor judgment, and impaired communication. In the later stages of the disease, a person will struggle with basic functions such as swallowing and walking.
When diagnosing, doctors look for several pathologies in the brain that are known features of the disease, including “plaques,” which are accumulations of the protein beta-amyloid outside neurons. They also look for “tangles” in the brain’s neurons, which are snarling strands of tau protein.
Currently, about half of Alzheimer’s patients also have another type of dementia. Scientists call multiple dementia diagnoses “mixed dementia.” Although Alzheimer’s disease and dementia are degenerative, they are not fatal diseases and the patient dies from a related complication such as pneumonia.
Read more: How does Alzheimer’s disease lead to death?
2. Frontotemporal dementia
Frontotemporal dementia, also called frontotemporal lobar degeneration (FTLD), is a term used to describe atrophy in the frontal and temporal lobes. About 60 percent of patients diagnosed with FTLD are aged between 45 and 60 years.
FTLD can be difficult to detect because the patient may not show symptoms of memory loss. Instead, they may have trouble speaking or show signs of personality change. Both can lead to misdiagnosis, as seen in Willis’ initial diagnosis of aphasia.
A subvariant, behavioral FTLD, causes drastic changes in a person’s personality. The person may develop a lack of inhibitions and say inappropriate things about their finances or intimate desires.
They may develop rude manners or use abusive language in public. Patients with this subvariant have also demonstrated impulsivity through inappropriate spending. Some may have psychotic episodes in the early stages of the disease, which include auditory or visual hallucinations.
3. Lewy body disease/The 4 main types of dementia
While FLTD is challenging to diagnose, Lewy body disease is difficult to manage by doctors. A drug that treats one symptom may make another symptom worse. Lewy body disease is associated with Parkinson’s disease, and about 80 percent of people with Parkinson’s will develop dementia.
For people with Lewy bodies, memory impairment may be mild or unnoticeable in the early stages. They may also have fluctuations in cognition so that moments of confusion are balanced with periods of alertness.
Patients with Lewy bodies will have one or more symptoms of Parkinson’s disease, such as tremors, stiffness, or slow movements. They may develop sleep problems, and as their cognitive decline progresses, they may have vivid hallucinations.
Lewy body is the second most common dementia in the elderly, aged 65 and over. Its symptoms can be confusing or initially unrecognizable, but biomarker testing and brain imaging help improve diagnostic options.
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4. Vascular dementia/The 4 main types of dementia
Vascular dementia (also known as cerebrovascular disease) is usually the result of a recent stroke. In the US and Europe, it is the second the most common cause of dementia, which accounts for 15 to 20 percent of cases. People who have had a stroke are at higher risk of developing vascular dementia.
When diagnosis of vascular dementia, clinicians use brain imaging and a recent history of stroke. This type of dementia can also occur if blood vessels are damaged and the brain is deprived of blood, nutrients and oxygen. Symptoms vary depending on where the blood vessel blockage occurs in the brain and can affect cognitive and physical abilities.
Vascular dementia alone is less common and accounts for about 5 to 10 percent of cases. It is more often seen together with Alzheimer’s disease in mixed dementia diagnoses.
Read more: Alzheimer’s disease is not the only cause of dementia