Dementia: What Happens In The Brain?

Dementia What Happens In The Brain

Dementia is the name given to a group of neurological diseases of which the major symptoms are a global decline in brain function that interferes with daily life. Meaning there are numerous different conditions which fall under the ‘Dementia umbrella’. Some conditions you may have heard of are Alzheimer’s Disease, Vascular Dementia, Parkinson’s disease, Huntington’s Disease or Dementia with Lewy Bodies (DLB).

Dementia  becomes more common after 65 years of age, but people in their 40s or 50s can also get dementia. Dementia is not a normal part of ageing, so not everyone gets dementia, however it is becoming more common.

With the different types, there are varying physical changes that occur in the brain due to dementia. Before we get to the changes that happen in the brain, let’s first go through how a healthy brain functions.

The Healthy Brain

A healthy brain gets its nutrients through a complex network of arteries, veins and capillaries. These blood vessels are strictly controlled and separate from the rest of the bloodstream, allowing only certain molecules to travel into the brain.

Different areas of the brain serve different functions. For instance, the area behind your ears (temporal lobes) processes speech and working memory. Towards the front of the brain is the limbic system which processes our desires and many emotions. The cerebellum is at the back of the brain and stores our muscle memory so we can do things without thinking, like riding a bike. Finally, the midbrain and brain stem control our bodily functions like heart rate, digestion and communicate between spinal cord and rest of the brain.

All these complex tasks are mediated by the connections between the brain cells (neurons). The connections between these neurons are called synapses. In the adult human brain, there are around 100 billion brain cells, each connected to its neighbours by 5-10,000 synapses.

 

Blood brain barrier

So, What Happens In The Brains Of People With Dementia?

There are various changes that occur with the different types of dementia. The two most common types are Alzheimer’s and Vascular Dementia. So we’ve outlined the specifics in those two conditions below. In addition, you can scroll down further for a series of great videos by Alzheimer’s Society.

 

Alzheimer’s Disease

The death of brain cells begins in the outer layers of the brain which involves memory, language and judgement. Physically the brain actually starts to shrink- and you can see that in the MRI image below. When Dr Alzheimer studied the brain of Alzheimer’s sufferers he noticed types of ‘deposits’ called Plaques and Tangles. The plaques impair the synapses mentioned earlier. As a result, signals cannot pass between the cells and therefore reduce the functioning of that area of the brain. Furthermore, tangles kill brain cells by preventing normal transport of food and energy, essentially starving the cells.

MRI Alzheimers Dementia
MRI Alzheimers Dementia.

 

In the early stages of Alzheimer’s symptoms can be very subtle. It begins with lapses in memory and difficulty finding the right words with everyday objects. Other symptoms may include:

  • Persistent and frequent memory difficulties, especially of recent events
  • Vagueness in everyday conversations
  • Apparent loss of enthusiasm for previously enjoyed activities
  • Taking longer to do routine tasks
  • Forgetting well known people or places
  • Inability to process questions and instructions
  • Deterioration of social skills
  • Emotional unpredictability.
Vascular Dementia

The term Vascular Dementia is the name given to a group of diseases which are caused by a problem of blood flow to the brain.

The most common cause of Vascular Dementia is a series of strokes, often with symptoms that develop over time. These strokes damage the areas of the brain responsible for learning, memory and language. Other symptoms may include lethargy, difficulty walking and losing bladder control.

People at risk of Vascular Dementia include smokers, diabetics, mild stroke sufferers and those with other arterial diseases and heart rhythm abnormalities. Other risk factors include high blood pressure or high cholesterol.

Once the nerve cells have died, they do not regenerate. Hence why it’s extremely important to apply a few simple preventative measures which we’ll be going through in more detail in the next few posts.

 

 

 

For more great information on the brain and the changes associated take a look at these short videos by Alzheimer’s Society.

Resources:

Fight Dementia

Alz.org

DemenctiaCentral

Alzheimers.org.uk

 

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