In February 2023, the family of actor Bruce Willis made an announcement about his health. The previous year, Willis had been diagnosed with aphasia, a disorder that prevents a person from speaking or understanding speech. As his condition worsened, physicians identified Bruce Willis has frontotemporal dementia.
Frontotemporal dementia is one of four main types of dementia. About 50 million people worldwide are living with dementia, and epidemiologists expect that number to triple by 2050. About two-thirds of those projected cases will likely be in middle and lower-income countries.
Advancements in medical technology now allow physicians 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 dementia, these are the four most common.
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1. Alzheimer’s Disease
Alzheimer’s disease is the most common form of dementia, constituting between 60 and 80 percent of dementia cases. It is a degenerative brain disease; people may live for years with no or mild symptoms.
Early symptoms of Alzheimer’s involve memory loss, like not remembering a recent conversation. Symptoms advance in severity to 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, physicians look for several pathologies in the brain that are known characteristics of the disease, including “plaques,” which are a buildup of the protein beta-amyloid outside the neurons. They also look for “tangles” inside the brain neurons, which are snarled strands of tau protein.
Currently, about half of Alzheimer’s patients also have another dementia type. Scientists call multiple-dementia diagnoses “mixed dementia.” Although Alzheimer’s and dementia are degenerative, they are not fatal diseases, and a patient dies from a related complication such as pneumonia.
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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 between the ages of 45 to 60.
FTLD can be difficult to detect because the patient might not show symptoms of memory loss. Instead, they may have trouble speaking or display signs of a personality change. Both can lead to misdiagnosis, as seen in Willis’ initial aphasia diagnosis.
One subvariant, behavioral FTLD, causes drastic changes to the person’s personality. The person might develop a lack of inhibition and say inappropriate things about their finances or intimate desires.
They may develop crude manners or use hurtful 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 that involve auditory or visual hallucinations.
3. Lewy Body Disease
Whereas FLTD is challenging to diagnose, Lewy body disease is difficult for physicians to manage. Medication that addresses one symptom might 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 body, memory impairment might be mild or unnoticeable in the early stages. They also might have cognition fluctuations so that moments of confusion are balanced with times of alertness.
Patients with Lewy body will have one or more symptoms of Parkinson’s, such as tremors, rigidity or slow movements. They can develop sleep issues, and as their cognitive decline increases, they can have vivid hallucinations.
Lewy body is the second most common dementia in older adults, ages 65 and older. Its symptoms can be confusing or initially unnoticeable, but biomarker testing and brain imaging are helping to improve diagnostic capabilities.
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4. Vascular Dementia
Vascular dementia (also known as cerebrovascular disease) is typically the result of a recent stroke. In the U.S. and Europe, it is the second most common cause of dementia, making up 15 to 20 percent of cases. People who have a stroke are at a higher risk for developing vascular dementia.
When diagnosing vascular dementia, clinicians use brain imaging and recent stroke history. This type of dementia can also occur if blood vessels are damaged, and the brain is deprived of blood, nutrients and oxygen. Symptoms vary based on where the blood vessel blockage occurred in the brain and may impact cognitive and physical abilities.
Vascular dementia on its own is less common and makes up about 5 to 10 percent of cases. It is more commonly seen along with Alzheimer’s in mixed dementia diagnoses.
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