Memory loss has a number of causes, one of which is dementia. Dementia is a progressive condition which causes deteriorating mental function which interferes with activities of daily living.
Dementia affects functions such as:
- Social behaviour
However, dementia is not the only cause of memory loss. Indeed, most people who suffer lapses in memory do not have dementia.
It is normal for memory to deteriorate a little as we get older: this doesn't necessarily mean we are developing dementia. It is normal for memory not to work well when we are distracted or concentrating on too many things at the same time. That's why memory lapses are more common if we are stressed. Physical and mental illness can all temporarily affect memory too.
Who gets dementia?
The World Health Organization (WHO) tells us there are about 50 million people in the world with dementia, and nearly 10 million developing the condition each year. By 2050, it is expected that there will be 135.5 million people in the world with dementia (over 2 million in the UK). So if dementia is affecting you or your loved one, you are certainly not alone.
The likelihood of getting dementia increases with age. Having said that, more than half of people will never develop dementia even if they reach the age of 95. You can find out more about the causes of dementia in the separate leaflet called Causes of Memory Loss and Dementia.
What are the symptoms of dementia?
The symptoms of all types of dementia are similar. They can be divided into three main areas:
Loss of mental ability
Memory problems are usually the most obvious symptom in people with dementia. Forgetfulness is common. As a rule, the most recent events are the first forgotten. For example, a person with early stages of dementia might go to the shops and then cannot remember what they wanted. It is also common to misplace objects.
Early memories stay longest. Events of the past are often remembered well until the dementia is severe. Many people with dementia can talk about their childhood and early life. As dementia progresses, sometimes memory loss for recent events is severe and the person may appear to be living in the past. They may think of themself as young and not recognise their true age.
Someone with dementia may not know common facts when questioned (such as the name of the Prime Minister). They may have difficulty remembering names or finding words. They may appear to be asking questions all the time.
Language problems can also develop. For example, someone with dementia may have difficulty understanding what is said to them or understanding written information. Problems with attention and concentration can also occur. It is common for someone with dementia not to be able to settle to anything and this can make them appear restless.
Disorientation. New surroundings and new people may confuse a person with dementia: they can become easily disorientated. However, in familiar places, and with old routines, they may function well. This is why some people with mild dementia cope well in their own homes. Losing track of time is also a common problem in someone with dementia. For example, not knowing if it is morning or afternoon, or what day it is. A person with dementia may get lost easily.
Learning new skills. Even clever people who develop dementia find it difficult to grasp new ideas or learn new skills. For example, how to use a new household gadget. The ability to think, calculate and problem-solve can be affected as intellect begins to fail. Difficulties with planning and decision making can develop.
Changes in mood, behaviour and personality
At first, someone with dementia may appear to be easily irritated or moody. It is often family or friends who notice this. Some people with early dementia recognise that they are failing and become depressed. However, many people with dementia are not aware that they have it. They may remain cheerful. The distress is often felt more by relatives who may find it difficult to cope.
More challenging behaviour may develop in some people over time. For example, in some cases, a person with dementia may become quite disinhibited. This means that he or she may say or do things quite out of character. This is often difficult for families and friends to cope with. Some people with dementia can also become agitated or even aggressive and this may be directed towards their carers. They may become suspicious or fearful of others. In some people, delusions (abnormal beliefs) and hallucinations (a false perception of something that is not really there) can occur. Visual hallucinations can be a common problem in dementia with Lewy bodies (DLB).
Mood, behavioural and personality changes may mean that someone with dementia is not able to interact with others in a social situation and they can become quite withdrawn. Sleep is often affected and pacing and restless wandering can become a problem for some.
Problems carrying out day-to-day activities
Difficulty with self-care usually develops over time. For example, without help, some people with dementia may not pay much attention to personal hygiene. They may forget to wash or change their clothes. Remembering to take medication can become an issue. The person may also have difficulty keeping up their home. Shopping, cooking and eating may become difficult. This can lead to weight loss. Driving may be dangerous and not possible for someone with dementia.
Lewy body dementia
Lewy body dementia is a particular form of dementia that can be mistaken for Alzheimer's disease. As well as symptoms seen in other forms of dementia, it can lead to symptoms similar to those seen in Parkinson's disease. Visual hallucinations (seeing things that aren't there) are also more common in people with Lewy body dementia. See the separate leaflet called Lewy Body Dementia.
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How does dementia progress?
Typically, symptoms of dementia tend to develop slowly, often over several years. In the early stages of the disease, many people with mild dementia cope with just a small amount of support and care. As the disease progresses more care is usually needed.
In the later stages of dementia, speech may be lost and severe physical problems may develop, including problems with mobility, incontinence and general frailty. This can make people more susceptible to other health problems such as infections. Often, people with dementia die from another health problem such as a severe chest infection. So, the dementia isn't the cause of their death but has contributed to it.
Some people can live for many years after dementia has been diagnosed. However, the condition does shorten lifespan. On average, once diagnosed with dementia, people are:
- In the mild early stage for one or two years.
- In the moderate stage, needing help looking after themselves for another two or three years.
- In a severe stage by four to five years after diagnosis, being completely dependent on carers and more or less completely inactive.
The average survival after diagnosis is 3-9 years, but people can survive for up to 20 years after being diagnosed with dementia.
How is dementia diagnosed?
Dementia is difficult to diagnose in some people. In the beginning, symptoms are often put down to other causes. There may also be a degree of protection by friends, carers and relatives who help the person to look after themself and, by doing so, cover up the person's inability.
Saying that, commonly, it is not the person with the symptoms but rather their relatives, carers or friends who have concerns that the person may have dementia. They may be concerned about the person's memory or behaviour. However, people with a high intellect or a demanding job may notice themselves that their mental ability is starting to fail.
Visit your doctor
The first step if you are concerned that you may be developing dementia is to see your doctor. Or, if you are worried that someone close to you may have dementia, you should encourage them to consult their doctor. They may agree for you to see their doctor with them.
Your doctor may suggest some special tests to look at your memory and mental ability, to see whether dementia is likely or not. This does not take long and is usually a series of questions or other exercises that your doctor asks you to complete.
Your doctor may also suggest some routine tests to make sure that there are no other obvious causes for your symptoms. For example, blood tests to look for infection, vitamin deficiencies, an underactive thyroid gland, etc. If infection is suspected, they may suggest a urine test, a chest X-ray or other investigations. They may also ask questions to make sure that your symptoms are not due to, for example, depression, any medicines that you may be taking, or excess alcohol intake.
Referral to a specialist
Referral for the opinion of a specialist is usually needed to confirm the diagnosis of dementia. This is usually to one of the following:
- A specialist memory clinic.
- A psychiatrist specialised in looking after older people.
- A specialist in the care of elderly people.
- A neurologist.
The specialist may be able to determine the likely cause of dementia and decide if any specific treatment may be helpful (see below). To help with this, they may suggest further investigations such as a magnetic resonance imaging (MRI) scan of the brain.
Other more sophisticated tests may be done if an unusual cause of dementia is suspected.
Usually referral is made to a specialist team as early as possible. This is partly so the person developing dementia and their carers can obtain advice about advance planning. In the earlier stages, people are better able to make decisions about how they wish to be cared for. They are also better able to decide who they want to manage their affairs once they become unable to do so themselves.
Special memory clinics give lots of information on dementia and how to manage it. Sometimes before dementia is established, there is an earlier phase called mild cognitive impairment. People with mild memory symptoms are often referred to the specialist clinics, so that they can have information early. This is in case their symptoms get worse and develop into dementia.
Research is underway to try to find ways of diagnosing dementia earlier and more easily, as well as to try to predict who may develop it. Researchers have been looking at proteins (biomarkers) in the blood or the fluid that bathes the brain (the cerebrospinal fluid) in people who have Alzheimer's disease or may go on to develop Alzheimer's disease. Further work is needed before any of this can be used to predict Alzheimer's disease.
Can I keep driving if I have been diagnosed with dementia?
This is very individual. Usually in the early stages of dementia it is safe to drive. In later stages it is likely that the ability to drive safely will be impaired. If you have been diagnosed with dementia in the UK, you must notify the DVLA. You may be able to continue driving a car or a motorcycle safely for some time, but you may be asked to have a driving test and/or your doctor may be asked to complete a medical report for the DVLA. Driving will then be subject to a medical assessment and will be reviewed each year.
Someone who has been diagnosed with dementia will not be able to continue to drive a bus (or other vehicle that carries passengers) or a lorry or large goods vehicle.
Can dementia be prevented?
Some things do show some promise.
Having risk factors for cardiovascular disease can increase your risk of developing all types of dementia. These risk factors include:
- Raised cholesterol levels.
- Drinking too much alcohol.
- Not doing enough physical activity.
- Being overweight.
- Having diabetes or high blood pressure.
Therefore, it would seem likely that doing something to modify these risk factors may reduce your risk of developing dementia. Stopping smoking, reducing excessive alcohol, and losing weight if you are overweight, for example, may all help to reduce your risk of dementia. Regular physical exercise is advised for all sorts of health benefits, including reducing the risk of dementia. One UK study suggested that a fifth of cases of Alzheimer's disease might have been related to lack of physical activity. It proposed that regular exercise might have actually prevented some of these cases.
Keeping your brain active may also help to reduce your risk of developing dementia. So, for example, consider reading books, doing puzzles, learning a foreign language, playing a musical instrument, taking up a new hobby, etc.
Many studies are going on to look into treatments which may help to prevent dementia. These include certain blood pressure medicines, omega-3 fatty acids, and brain training exercises, as well as the strategies discussed above. However, there is not yet convincing evidence available for any of these.
Further research is ongoing to try to find other ways of preventing dementia.
Further reading and references
Dementia: assessment, management and support for people living with dementia and their carers; NICE Guideline (June 2018)
Dementia, disability and frailty in later life – mid-life approaches to delay or prevent onset; NICE Guidelines (October 2015)
Dementia; NICE Quality standard, June 2019
Dementia: independence and wellbeing; NICE Quality Standard, April 2013
Dementia; NICE CKS, May 2021 (UK access only)
Dementia Fact Sheet; World Health Organization (WHO), April 2016
Donepezil, galantamine, rivastigmine and memantine for the treatment of Alzheimer's disease; NICE Technology Appraisal Guidance, March 2011 - updated June 2018
Robinson L, Tang E, Taylor JP; Dementia: timely diagnosis and early intervention. BMJ. 2015 Jun 16350:h3029. doi: 10.1136/bmj.h3029.
Health matters: midlife approaches to reduce dementia risk; Public Health England Guidance, March 2016 - updated 28 June 2021
Laver K, Dyer S, Whitehead C, et al; Interventions to delay functional decline in people with dementia: a systematic review of systematic reviews. BMJ Open. 2016 Apr 276(4):e010767. doi: 10.1136/bmjopen-2015-010767.
Howard R, McShane R, Lindesay J, et al; Donepezil and memantine for moderate-to-severe Alzheimer's disease. N Engl J Med. 2012 Mar 8366(10):893-903. doi: 10.1056/NEJMoa1106668.
Living with dementia - Planning ahead; Alzheimer's Society