Most people become more forgetful as they get older, but dementia is different. It describes a series of symptoms, such as progressive memory loss, which occurs when the brain has been damaged by disease.

Dementia is more common than people realise and occurs mainly in people over the age of 65. It can however (although rarely), also occur in younger people (<65 years of age) and may run in families. About 10% of people diagnosed with young onset dementia have a genetic form of dementia. There are over 850,000 people living with dementia in the UK and this is set to rise to over one million by 2025. Because people are living for longer the risk of developing dementia gradually increases in people over the age of 65; over one-in-three people over the age of 90 years will develop dementia, and more people are living into their 90s.

Experiencing dementia can be very frightening, leaving people feeling vulnerable, depressed, marginalised and not in control of their life. They may feel angry or upset that this is happening to them. They may feel ashamed that they can no longer function independently and have to increasingly rely on others for help. They might even be in denial that there a problem, so they try to hide some of their difficulties, or attempt to explain them away. The emotional toll can be devastating and over time, they can lose interest in socialising, become increasingly introverted, and lose their self-confidence.

Recognising dementia: what are the symptoms?

Regardless of which type of dementia is diagnosed and what part of the brain is affected, each person will experience dementia in their own unique way.

Common symptoms of dementia include:

  • Lapses in memory, and memory loss, for example, difficulty retaining new information, forgetting the way home, experiencing confusing with names, and losing items regularly
  • Impaired cognitive function, for example, difficulty concentrating and focusing on specific tasks, confusion in unfamiliar surroundings, or disorientating for time and/or place (i.e. getting up in the middle of the night to go to work despite being retired)
  • Difficulty communicating, for example, finding reading and writing harder, struggling to articulate the right words during a conversation, and being very repetitious
  • Difficulty coping with daily tasks, such as making a cup of tea or getting dressed.

Becoming increasingly forgetful does not necessarily mean that you have dementia, as other factors, including age, stress, depression and diet, can play a role. However, if the symptoms persist, it is important to seek professional help as early on as possible.

What causes dementia?

The brain is made up of nerve cells (neurones) that communicate with each other by sending messages. Dementia damages these nerve cells in the brain so messages can't be sent from and to the brain effectively. This in turn prevents the body from functioning normally.
Dementia is a collective term for a range of progressive neurological conditions that affect the brain. There are over 200 causes of dementia, but the most common are:

  • Alzheimer's disease - caused by changes in the structure of the brain with a build up of amyloid plaques (abnormal deposits of protein), neurofibrillary tangles (containing tau) and imbalances in a chemical called acetylcholine which is required for transmission of messages
  • Vascular dementia - caused by problems in the supply of blood to the brain, commonly due to strokes or a series of small strokes, known as Transient Ischaemic Attacks (TIAs), which cause areas of cell damage in the brain
  • Dementia with Lewy bodies - affects movement and motor control
  • Frontotemporal dementia - tends to affect younger people, usually aged 45 to 65 years, and can be difficult to diagnose
  • Mixed dementia - usually combination of alzheimer's disease and vascular dementia

Dementia affects each person differently depending on the brain regions affected. The brain is made up of two hemispheres and each has four lobes: frontal, temporal, parietal and occipital. Each lobe has a different function and, depending on which part is damaged by dementia, it can lead to different signs and symptoms.

The frontal lobes control emotional expression, personality, problem solving, judgement, motor function, language, motivation and social behaviour. The temporal lobes control memory, speech, language comprehension, auditory and visual perception, emotional responses and facial recognition. Frontotemporal dementia predominantly affects the frontal lobes (behaviour and personality) and this can cause disinhibition and inappropriate social behaviour. Eating patterns can also be affected, with people suddenly bingeing on food, especially sweet foods. This form of dementia can sometimes be confused with depression, stress, anxiety, psychosis or obsessive compulsive disorder (OCD)

The parietal lobes control learnt skills such as reading, writing and calculations. They also control recognition of objects, spatial awareness and the ability to perform complex skills such as driving and constructing things.

The occipital lobes control spatial processing, ability to determine between different colours, spatial awareness, colour and object recognition, and could also lead to difficulties with activities that require hand and eye coordination such as picking up items.

In Alzheimer's disease, among the areas often damaged first are the hippocampus and its connected structures. The hippocampus is located in the medial temporal lobe of the brain and is needed for retrieval of memories.

Individuals with damage to this area struggle to form new memories or learn new information. A person with Alzheimer's may struggle to remember what they did earlier that day, or what they have just said, meaning they may repeat themselves in conversation.

In the earlier stages of alzheimer's (with a damaged hippocampus but an intact cortex) an individual may remember a childhood holiday but struggle to remember what they ate for breakfast that morning.

In Alzheimer's disease, the amygdala is generally affected later than the hippocampus. The amygdala is an almond-shaped section of nervous tissue located in the temporal (side) lobe of the brain and is part of the limbic system within the brain, which is responsible for emotions, survival instincts, and memory. Thus, a person with Alzheimer's will often recall the emotional aspects of something even if they don't recall the factual content. They may therefore respond more according to how they feel about a place or person than in a more logical way.

As Alzheimer's disease progresses, additional areas and lobes become affected with the cortex becomes thinner (cortical atrophy) so memories from longer ago are lost.

Damage to the left hemisphere is linked to problems with semantic memory (that portion of long-term memory that processes ideas and concepts that are not drawn from personal experience) and language, so someone may struggle to find the right word for something.

Damage to the visual system in the temporal lobes makes recognising familiar faces and objects more difficult. The person may seem to forget who a familiar person is. However, because the pathways for vision and hearing are separate, they may still know who that person is once they hear them speak. The person with Alzheimer's disease may also respond to someone at an emotional level even if they seem not to recognise them.

If there is damage to the right parietal lobe then the person might have problems with judging distances in three dimensions. Navigating stairs is a common difficulty.

As the damage spreads to the frontal lobes, someone with Alzheimer's may struggle with decision-making, planning or organising (e.g. family finances). A more complex task with a sequence of steps, such as following a new recipe, might also become much harder.

In contrast to these losses, many abilities are retained, particularly those acquired long ago. Learned skills such as dancing or playing the piano rely on procedural memories, and so are mostly stored deep within the brain. In alzheimer's disease, these skills are often retained the longest.

The signs and symptoms of vascular dementia depend on which area of the brain has been affected. Language, reading, writing and communication can be affected in vascular dementia. Memory problems may not be an issue initially, if this area of the brain has not been damaged, although they may occur later on.

In dementia with Lewy bodies individuals are be prone to falls, experience a tremor (similar to Parkinson's disease, may have trouble swallowing, shuffle when they walk, experience disrupted sleep patterns due to intense dreams/nightmares and also experience visual (and auditory) hallucinations. Memory is often less affected than with other types of dementia, but a person might experience sudden bouts of confusion which can change on an hourly basis.

Diagnosing and treating dementia: what are the options?

If you are worried that you have symptoms associated with dementia it is important to see your GP as some treatable medical conditions may mimic dementia and can affect a person's memory or brain function.

These treatable conditions include conditions such as an underactive thyroid, delirium (Infections and/or electrolyte problems) vascular problems related to circulatory issues, vitamin B12 deficiency, sleep apnoea, stress and depression. If after appropriate investigation and treatment the problems persist then it is worthwhile requesting a specialist psychiatric assessment for a definitive diagnosis and advice regarding treatment options and support, which can come from a range of organisations, including health and social care professionals, charities, and the voluntary sector.