1.1. Describe types of dementia and their causes

This guide will help you answer 1.1. Describe types of dementia and their causes.

Dementia is an umbrella term used to describe a set of symptoms affecting memory, thinking, and social abilities significantly enough to interfere with daily life. It is not a single disease but rather a broad category that includes various types. Each type has its own causes and characteristics. Understanding these can help health and social care workers provide tailored support and effective care.

What is Dementia?

Dementia itself is not a specific disease. It refers to a group of conditions that cause progressive damage to the brain. Over time, this leads to difficulties with cognitive functions, behaviour, and the ability to perform everyday tasks.

Common Types of Dementia

There are several types of dementia, each with specific features and causes.

Alzheimer’s Disease

Alzheimer’s disease is the most common type of dementia. It accounts for around 60–70% of dementia cases in the UK. It is a progressive condition, meaning symptoms worsen over time.

Cause:

Alzheimer’s disease is caused by a build-up of proteins in the brain. Two proteins, amyloid and tau, form plaques and tangles in the brain. These disrupt communication between nerve cells (neurons). Over time, neurons die, and parts of the brain shrink.

Factors contributing to Alzheimer’s include:

• Increased age – risk rises sharply after age 65.
• Genetic disposition – certain genes, like APOE4, increase risk.
• Cardiovascular health – issues like high blood pressure and cholesterol may increase chances.
• Lifestyle factors – smoking, lack of physical activity, and poor diet can play a role.

Vascular Dementia

Vascular dementia is the second most common type. It results from reduced blood flow to the brain, leading to damage in brain tissues.

Cause:

This type is caused by conditions affecting blood supply to the brain. Common causes include:

• Strokes – A blockage or bleeding in the brain interrupts blood flow.
• Small vessel disease – Narrowing or damage to tiny blood vessels in the brain.
• Heart problems – Conditions like atrial fibrillation or heart disease can impact blood supply to the brain.

Risk factors include smoking, diabetes, high cholesterol, and high blood pressure. The progression of vascular dementia can be stepped, with symptoms worsening after each event like a stroke.

Lewy Body Dementia

Dementia with Lewy bodies (DLB) is caused by abnormal protein deposits in the brain known as Lewy bodies. These deposits affect how brain cells communicate.

Cause:

The main driver of Lewy body dementia is the accumulation of alpha-synuclein proteins in nerve cells. These deposits disrupt signalling, especially in areas responsible for movement, memory, and thinking.

People with Parkinson’s disease may develop Lewy body dementia later in life. It is thought to share similarities with both Parkinson’s disease and Alzheimer’s disease.

Symptoms can fluctuate, meaning cognition and alertness may vary significantly throughout the day.

Frontotemporal Dementia (FTD)

Frontotemporal dementia primarily affects the front and side parts of the brain. This type of dementia tends to appear earlier, often affecting people under 65.

Cause:

FTD is caused by damage to the nerve cells in the frontal and temporal lobes of the brain. Abnormal protein deposits disrupt cell functionality, eventually leading to cell death.

There are several types of FTD, including:

1. Behavioural Variant FTD – Affects personality, behaviour, and decision-making.
2. Primary Progressive Aphasia – Impacts language skills, including speaking and understanding words.

Genetic mutations play a key role in many FTD cases. Families with a history of FTD are more likely to inherit genes that increase their risk.

Mixed Dementia

Mixed dementia occurs when someone has two or more types of dementia at the same time. The most common combination is Alzheimer’s disease and vascular dementia. Symptoms may overlap depending on the specific types involved.

Cause:

The causes of mixed dementia depend on the individual types present. For example, it may involve blocked blood vessels (vascular dementia) and protein deposits (Alzheimer’s disease).

Mixed dementia is often underdiagnosed because symptoms can mimic those of a single type. Advanced brain scans and assessments may detect the condition more effectively.

Less Common Types of Dementia

While Alzheimer’s, vascular, Lewy body, and frontotemporal dementia are the most recognised types, others occur less frequently:

Parkinson’s Disease Dementia

Parkinson’s disease dementia develops in people with Parkinson’s disease. It shares overlapping symptoms with Lewy body dementia.

Cause:

This type is caused by changes to the brain over time, including alpha-synuclein protein build-up. Individuals often develop dementia after living with Parkinson’s for several years.

Huntington’s Disease Dementia

People with Huntington’s disease may develop dementia as part of the condition’s progression.

Cause:

Huntington’s disease is caused by a genetic mutation resulting in the production of abnormal proteins. These damage nerve cells, leading to problems with thinking, memory, and mood.

Creutzfeldt-Jakob Disease (CJD)

CJD is a rare dementia caused by abnormal proteins called prions. It progresses rapidly, often leading to severe impairment.

Cause:

Prions are misfolded proteins that infect and damage healthy brain cells. This is a rare condition but can be inherited or develop spontaneously. In some cases, it is linked to exposure to contaminated tissue.

Other Types of Dementia:

Some types are even rarer, including:

• Down syndrome-associated Alzheimer’s – Alzheimer’s is more common in people with Down syndrome.
• Korsakoff Syndrome – Linked to long-term alcohol misuse affecting memory and cognition.
• HIV-associated Dementia – A result of brain damage caused by HIV infection.

Recognising Risk Factors

Understanding the causes of dementia includes recognising risk factors. Common factors affecting dementia risk include:

• Age – Dementia risk increases with age, especially after 65.
• Family History – Certain inherited genes increase risk.
• Lifestyle Choices – Smoking, lack of exercise, and poor diet are contributing factors.
• Health Conditions – Diabetes, heart disease, and high blood pressure elevate risk.
• Brain Injuries – Past head trauma increases the likelihood of developing dementia.

How Causes Relate to Symptoms

The causes of dementia directly affect the areas of the brain that control memory, thinking, and behaviour. For example:

• Protein build-up in Alzheimer’s disrupts connections between nerve cells, leading to memory loss.
• Vascular damage in vascular dementia impacts cognitive processes like problem-solving.
• Temporal lobe degeneration in frontotemporal dementia results in difficulty understanding language or controlling behaviour.

Understanding the specific cause helps health and social care workers identify symptoms and plan care more effectively.

Final Thoughts

The types of dementia vary greatly, but all result from damage to the brain in different ways. Whether through protein deposits, reduced blood flow, or inherited genetic mutations, each form has its unique characteristics. As a health and social care professional, recognising these types and understanding their causes is fundamental to providing compassionate and tailored care.