Bruce Willis diagnosed with dementia: 5 types of the illness to know

Dementia, a generic term for the impaired ability to remember, think, or make decisions about everyday activities, has been in the spotlight since Thursday, after the family of US actor Bruce Willis announced that he was diagnosed with frontotemporal dementia.

Around one in 10 people aged 60 and above in Singapore suffers from dementia, according to the Ministry of Health. There are over 100 forms of dementia, according to the Alzheimer’s Disease International, each with different causes and symptoms.

Here are five common types of dementia.

1. Alzheimer’s disease

According to the World Health Organisation (WHO), this disease contributes to 60 to 70 per cent of dementia cases worldwide.

The condition is caused by a build-up of certain kinds of proteins in and around brain cells. Such a build-up causes a decrease in chemical messengers that send messages, or signals, between brain cells.

Over time, various areas of the brain start to shrink and the first area usually affected is one’s memories.

A progressive disease, Alzheimer’s leads gradually to worsening symptoms over the years, causing memory loss and affecting thinking skills that lead to the loss of one’s ability to respond to people and surroundings, and to perform simple tasks such as eating and bathing.

On average, those who suffer from this disease have a life expectancy of between eight and 10 years after diagnosis.

2. Vascular dementia

According to John Hopkins Medicine, this is second-most common form of dementia worldwide, after Alzheimer’s disease.

It is caused by poor blood flow or injury to blood vessels in the brain, mostly because of strokes. Depending on the size and location of the area affected, one may either become forgetful, or, in serious cases, have trouble thinking clearly and significant memory problems that disallow one to function normally.

Heart diseases and atherosclerosis (hardening of the arteries) also raise the risk of one contracting vascular dementia.

According to Singapore’s DementiaHub website, treating and controlling the risk factors, such as high blood pressure, diabetes, high cholesterol and smoking, may help slow its progression and reduce stroke recurrence.

The lifespan for someone with this form of dementia is around five years after diagnosis as one is more likely to die from a stroke or a heart attack than from the disease itself, reported the Alzheimer’s Society.

3. Lewy body dementia (LBD)

This type of dementia occurs when there is an unusual build-up of structures called Lewy bodies inside one’s brain cells, said DementiaHub.

Lewy bodies affect specific areas of the brain, resulting in memory, thinking, movement and behavioural issues.

Diagnosing this form of dementia can be challenging due to its similar symptoms with other diseases such as Alzheimer’s, Parkinson’s disease and schizophrenia, said the Lewy Body Dementia Resource Center.

Symptoms can include slowness, tremors, rigid muscles and vivid visual hallucinations. Those diagnosed with Lewy Body dementia could fall more often due to their increased rigidity, instability and slow gait.

Their life expectancy is about six years after diagnosis as the disease increases a person’s risk of falls and infections.

4. Frontotemporal dementia

This is the type of dementia that Willis was diagnosed with.

According to John Hopkins Medicine, this form of dementia occurs when one’s nerve cells in the frontal and temporal lobes of the brain are lost, causing the lobes to shrink.

After the lobes have shrunk, a person with this disease may experience significant changes in personality, behaviour and emotion, as well as language difficulties.

The life expectancy for someone diagnosed with this form of dementia is about six to eight years.

5. Mixed dementia

According to Alzheimer’s Society, mixed dementia is a condition where a person has more than one type of dementia. The most common mix is the Alzheimer’s disease and vascular dementia. In some cases, a person may get all three conditions – Alzheimer’s disease, vascular dementia and LBD.

Depending on which part of one’s brain is affected, the symptoms vary. In some, they are often similar or identical to Alzheimer’s or other types of dementia. In others, one’s many symptoms may indicate that there are more than one type of dementia present.

The life expectancy of this type of dementia is unclear.

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Other diseases that lead to dementia

Besides the five common types of dementia mentioned, other illnesses, such as Parkinson’s disease, Huntington’s disease, and Creutzfeldt-Jakob disease, also cause one to develop dementia as part of their symptoms.

Rarer forms of dementia include the Wernicke-Korsakoff syndrome and posterior cortical atrophy.

The former is a condition caused by drinking excessive alcohol over a prolonged period of time, while the latter is due to the degeneration of the cells at the back of the brain that first causes eyesight problems.

Although dementia itself is not inherently life-threatening, it can lead to an increased risk in other serious illnesses such as pneumonia, infections and fall-related injuries.