Overview of Dementia

I am by no means a dementia expert so this information was all collected from an amazing series of videos by the Alzheimer’s Society.

Dementia is not a disease but the name for a group of symptoms that commonly include problems with:

Memory

Thinking

Problem Solving

Language

Visual Perception

For people with dementia, these symptoms have progressed enough to affect daily life and are not a natural part of aging, as they’re caused by different diseases (I highlight some of them below).

All of these diseases cause the loss of nerve cells, and this gets gradually worse over time, as these nerve cells cannot be replaced.

As more and more cells die, the brain shrinks (atrophies) and symptoms sharpen. Which symptoms set in first depends on which part of the brain atrophies—so people are impacted differently.

source — you can see the black areas expanding as nerve cells die and atrophy progresses.

For example, if the occipital lobe begins to decline, then visual symptoms would progress, whereas losing the temporal lobe would cause language problems…

Other common symptoms impact:

Day-to-day memory

Concentration

Organization

Planning

Language

Visual Perception

Mood

There is currently no cure…

Before moving on to cover recent research surrounding language problems, it’s important to not that most research is disease-specific. Therefore, I’lll briefly cover the four types of Dementia.

All of this information again comes from the series of videos created by the Alzheimer’s Society.

Alzheimer's Disease

The most common type of dementia is Alzheimer’s Disease (AD), and for this reason, it’s also the most understood (you’ll notice this in the research).

A healthy brain contains proteins (two of which are called amyloid and tau), but if the brain starts to function abnormally, these proteins form abnormal deposits called plaques and tangles.

These plaques and tangles damage nerve cells, which causes them to die and the brain to shrink, as shown above.

The hippocampus is usually the first area of the brain to decline in performance when someone has AD. This is unfortunately where memories are formed, so people will often forget what they have just done and may therefore repeat themselves in conversation.

Recent memories are lost first, whereas childhood memories can still be retrieved as they depend less on the hippocampus. Additionally, emotions can usually be recalled as the amygdala is still intact, whereas the facts surrounding those emotions can be lost.

AD gradually progresses, so symptoms worsen and become more numerous slowly over time.

Vascular Dementia

The second most common type of dementia is vascular dementia, which is caused by problems with the brain’s blood supply.

Nerve cells need oxygen and nutrients to survive, so without them they become damaged and die. Therefore, when blood supply is interrupted by a blockage or leak, significant damage can be caused.

Like with AD, symptoms depend on which parts of the brain are impacted. When the parts damaged are responsible for memory, thinking, or language, the person will have problems remembering, thinking or speaking.

Vascular dementia can be caused by strokes. Sometimes one major stroke can cause it, but in other cases a person may suffer from multiple smaller strokes that gradually cause damage.

The most common cause of vascular dementia is small-vessel disease, which gradually narrows the vessels in the brain. As the narrowing continues and spreads, more of the brain gets damaged.

Vascular dementia can therefore have a gradual progression like AD or, if caused by strokes, a step-like progression with symptoms worsening after each stroke.

Dementia with Lewy Bodies

Closely related to AD, but less common, is a type of dementia called dementia with Lewy bodies.

Lewy bodies are tiny clumps of protein that develop inside nerve cells in the brain. This prevents communication between cells, which causes them to die.

Researchers have not yet identified why Lewy bodies form or how. We do know, however, that they can form in any part of the brain, which, again, leads to varying symptoms.

People can have problems with concentration, movement, alertness, and can even have visual hallucinations. These hallucinations are often distressing and lead to sleep problems.

Dementia with Lewy bodies progresses gradually and spreads as more nerve cells get damaged, so memory is always impacted eventually.

Frontotemporal dementia

The last type of dementia I’ll cover is frontotemporal dementia (FTD), which is a range of conditions in which cells in the frontal and temporal lobes of the brain are damaged.

FTD is again a less common type of dementia but is surprisingly more likely to effect younger people (below 65).

The frontal and temporal lobes of the brain control behavior, emotion, and language, and symptoms occur in the opposite order depending on which lobe is impacted first.

The frontal lobe is usually the first to decline in performance, so changes begin to show through a person’s personality, behavior, and inhibitions.

Alternatively, when the temporal lobe is impacted first, a person will struggle with language. For example, they may struggle to find the right word.

FTD is thought to occur when proteins such as tau build up in nerve cells, but unlike the other causes, this is likely hereditary.

Eventually as FTD progresses, symptoms of frontal and temporal damage overlap, and both occur.