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Diagnosis and assessment

If you, or someone you are close to, have been feeling confused, agitated or forgetful, it may be a good idea to visit the GP. If you are concerned about someone else, you may like to suggest that you accompany them on the visit.

It is possible that these symptoms are an indication of dementia. This term describes a group of symptoms caused by the physical impact of disease or injury on the brain. There are a number of different conditions that lead to dementia, including Alzheimer's disease, vascular disease (including stroke) and dementia with Lewy bodies.

Each person will experience dementia in his or her own individual way, but there will usually be:

  • a decline in memory, reasoning and communication skills
  • a gradual loss of the skills needed to carry out daily activities
  • confusion.

For more information about dementia, see the range of factsheets available from Alzheimer's Society, including Factsheet 400, What is dementia?, 401, What is Alzheimer's disease?, 402, What is vascular dementia?, 403, What is dementia with Lewy bodies? and 404, What is frontotemporal dementia?.

Why get a diagnosis?

A proper diagnosis of dementia is essential, in order to:

  • rule out other conditions that may have symptoms similar to dementia and that may be treatable, including depression, chest and urinary infections, severe constipation, vitamin and thyroid deficiencies and brain tumours
  • rule out other possible causes of confusion, such as poor sight or hearing; emotional changes and upsets, such as moving or bereavement; or the side-effects of certain drugs or combinations of drugs
  • access advice, information and support (emotional, practical and financial) from social services, voluntary agencies and support groups
  • allow the person with dementia to plan and make arrangements for the future.

As drugs for treating different conditions become available, it is becoming increasingly important to identify which type of dementia the person has. For example, drugs are already available to treat some people with Alzheimer's disease and some people with dementia with Lewy bodies, but these drugs are ineffective in the treatment of Pick's disease (another form of dementia), and may actually worsen symptoms. See Factsheet 407, Drug treatments for Alzheimer's disease.

Making a diagnosis

Making a diagnosis of dementia is often difficult − particularly in the early stages. A definite diagnosis of the cause may only be confirmed after death, at post mortem or, in very rare instances, through a brain biopsy.

The time it takes to make a diagnosis can vary. If scans and other investigations are required, it could be 4-12 weeks, depending on waiting lists. If the person is in the early stages of dementia, a 6-12 month period of monitoring may be required before a diagnosis can be made.

Step 1: Assessment by a GP

If you are concerned that you, or someone you are close to, may have dementia,  the first person to consult is the GP. You may see the GP in their surgery or they may prefer to make a home visit. If dementia is suspected, it is often easier to assess and observe the person's behaviour in the home. It then becomes clearer exactly what the problems are. The GP will assess the person through:

  • Analysis of background information − You can expect the GP to spend some time talking to you and (if you are simply accompanying someone) the person you are concerned about, to try to establish some of the symptoms. The GP will look at the person's medical history and that of other family members.
  • Physical examinations and tests − The GP will normally carry out a physical examination and may perform a number of tests, such as blood and urine tests, to identify other conditions that may be causing confusion.
  • Mental tests − The GP may ask a series of questions designed to test thinking and memory.

The GP will have access to some services, such as community nursing. If there is a probable diagnosis of dementia, or the person is having trouble managing, the GP can refer them to the social services.

At the end of the assessment, the GP should communicate their findings in an appropriate way and discuss what action needs to be taken. They may feel able to make a diagnosis, or they may wish for further assessment to make sure. In some cases they may want to refer the person to a memory clinic or other specialist service for a fuller assessment.

Step 2: Referral to a specialist

The GP is the usual person to make a referral to a specialist. If you feel that a referral would be helpful and the GP does not suggest it, do press for it. You are entitled to ask for a referral to a memory clinic or other specialist service for a second opinion or for support, and access to services that such a referral may give. A consultant will have more specialised knowledge and experience of dementia than the GP, and will have access to more specialised investigations, such as brain scans and memory testing.

Your GP will make the referral to a consultant in a particular specialty. The specialty may depend on the age of the person concerned, their symptoms and what is available in your particular area. The main types of consultant are as follows:

  • Neurologists specialise in disorders of the brain and nerve pathways. Some neurologists have particular experience in diagnosing dementia. 
  • Specialists in medicine for older people (sometimes called geriatricians) specialise in the physical illnesses and disabilities associated with old age and in the care of older people. If the person being diagnosed has reached retirement age they may be referred to one of these specialists to see whether their symptoms are due to a physical illness, or to find out whether they are suffering from a physical illness as well as dementia.
  • General adult psychiatrists specialise in diagnosing and treating a wide range of mental health problems. A younger person may be referred to a psychiatrist to assist in the diagnosis.
  • Old age psychiatrists are psychiatrists who have further specialised in the mental health problems of older people, including dementia. They may sometimes also offer support to younger people with dementia.

The consultant usually works within a specialist team − alongside a number of fully qualified doctors at various stages of further training in that particular speciality. Although you may not always see the consultant in person, he or she is ultimately responsible for your case and will discuss it with the doctor concerned. The consultant also usually works with other professionals, including nurses, psychologists, occupational therapists and social workers. Each of these members contributes their own knowledge, skills and advice to the team.

Step 3: Assessment

Assessment may take place in the home, in an outpatients department, in a day hospital over several weeks or, very occasionally, as a hospital inpatient. The specialist will carry out their assessment through:

  • Analysis of background information − As with the GP, an assessment is likely to include time spent talking to the person being diagnosed and those close to them.
  • Physical examinations and tests − A physical examination and/or tests will be undertaken, if they have not already been carried out by the GP.
  • Memory assessment - The person being diagnosed may see a clinical psychologist or neuropsychologist for a more detailed assessment of memory and other thinking processes. This consists of a range of 'pen and paper' type tests and questions that will look at things like memory, verbal and non-verbal abilities. These tests can be very good at helping to decide the type of problem a person may have, particularly in the early stages. The assessment can be used as a baseline to measure any changes over time which can also help with making a diagnosis. 
  • Scans − The person might be given a brain scan. A brain scan can identify conditions such as strokes, brain tumour and hydrocephalus (a build-up of fluid inside the brain). There are several types of brain scan:
    − CT or CAT (computerised axial tomography) scans are a way of taking pictures of the brain using X-rays and a computer
    − MRI (magnetic resonance imaging) scans also use a computer to create an image of the brain but, instead of X-rays, they use radio signals produced by the body in response to the effects of a very strong magnet contained within the scanner.
    − SPECT (single photon emission computerised tomography) scans look at the blood flow through the brain, rather than at the structure of the brain.

After the assessment, the consultant will send a report to the GP. CT and MRI scans may show brain shrinkage (atrophy), while SPECT and PET scans show areas of loss of function. Memory tests can also show problems in particular areas. The pattern of these changes helps to diagnose the cause of the dementia. A scan that shows no unexpected changes in the brain does not rule out conditions such as Alzheimer's disease because in the early stages of the disease the changes can be difficult to distinguish from normal ageing. The consultant may discuss their findings or may refer the person back to the GP for this information. In some cases the consultant may wish to see the person again after some months to observe any changes before making a diagnosis.

Tips: Getting the most from a consultation

Whether you are attending the appointment for yourself or for someone you are supporting, it may be useful to do the following:

  • Write down any questions or worrying signs beforehand to ask the GP or specialist. It can be difficult to remember everything you want to say during a consultation. 
  • Write down any important points the doctor makes during the consultation.
  • Ask a doctor, or any other professional, to explain words or phrases if you do not understand.
  • Ask a doctor to write down any medical terms, particularly if English is not your first language.

Step 4: Explaining the diagnosis

Doctors may differ in their views on what to tell their patients about a diagnosis of dementia. The person with dementia has the right to be told their diagnosis − particularly if this gives them the opportunity to put their affairs in order. However, in some circumstances a professional may feel that:

  • they should only offer the diagnosis of dementia if the patient asks, or seems to want to know
  • the knowledge that they have dementia will be too much for the person to cope with
  • it is better to use a term such as 'memory problems' if this may be more easily understood or seems more appropriate.

Most doctors will inform those close to the person concerned of the diagnosis of dementia or possible dementia. In some cases it may be left to the relatives or friends to decide whether to tell the person that they have dementia. This will depend on the kind of relationship they have with the person, and what they feel the person would want to know.

If you feel that the doctor is avoiding the issue, don't hesitate to ask for an explanation.

Step 5: Ongoing assessment

Once the diagnosis is confirmed, the GP should arrange to see the person with dementia from time to time to assess changes and discuss any problems. He or she may refer the person with dementia to a specialist for help in assessing changes, and for advice on ways to deal with specific difficulties. The GP is also responsible for the general health of the person with dementia.

The GP and a hospital specialist will usually jointly prescribe any treatment for dementia. The arrangement will depend upon the person's situation, where they live, and what medication they are already taking.

If you or someone you are close to is diagnosed with dementia, don't be afraid to seek help from your GP, or from local support groups, if you feel you need it. For information about where to get support and further advice once a diagnosis has been made, see Factsheet 471, After a diagnosis.

For details of Alzheimer's Society services in your area, visit alzheimers.org.uk/localinfo
For information about a wide range of dementia-related topics, visit alzheimers.org.uk/factsheets

Factsheet 426

Last updated: February 2011
Last reviewed: December 2010

Reviewed by: Dr Yvonne McCulloch, Neuropsychologist, Imperial College Healthcare Trust

This factsheet is also available in Arabic, Bengali, Chinese, French, Gujarati, Polish, Punjabi, Somali and Tamil.

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Alzheimer's Society helpline

If you have any questions about the information on this factsheet, or require further information, please contact the Alzheimer’s Society helpline.

0300 222 11 22

Diagnosing dementia

Visit our section about diagnosing dementia.

Copyright and permission requests

Find out how you can request permission to use our information beyond this site.

       


Order now

Order a free copy of this publication

Alzheimer's Society helpline

If you have any questions about the information on this factsheet, or require further information, please contact the Alzheimer’s Society helpline.

0300 222 11 22

Diagnosing dementia

Visit our section about diagnosing dementia.

Copyright and permission requests

Find out how you can request permission to use our information beyond this site.