Mild Cognitive Impairment, from the Alzheimer's Society, U.K.

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Mild cognitive impairment

Mild cognitive impairment (MCI) is a relatively recent term, used to describe people who have some problems with their memory but do not actually have dementia. This factsheet explains the link between MCI and dementia, and looks at possible treatments.

Background

Often, people are not diagnosed with dementia until their symptoms begin to affect their quality of life and their ability to carry out everyday activities. In recent years, however, treatments that can improve the symptoms of Alzheimer's disease have become available (Aricept, Reminyl, Exelon and Ebixa), see Factsheet 407, Drugs to treat Alzheimer's disease. Other treatments that may slow down the progression of the disease in the brain are also being developed. It is important that people with Alzheimer's disease are identified as early as possible, so that they can benefit from these treatments in the future. Identifying people with mild cognitive impairment (MCI) is one way to try to achieve this.

What is MCI?

MCI is a descriptive term rather than a specific medical condition or disease. It describes memory loss apparent to the individual, and those around them. The memory loss is supported by formal memory tests, but other features of dementia are absent.

There are many different reasons why people may have some mild problems with their memory. Some people will be in the early stages of Alzheimer's disease or another form of dementia. Others will have MCI as a result of stress, anxiety, depression or physical illness. A doctor may, or may not, be able to say what process underlies a diagnosis of MCI in an individual.

People with MCI usually have impaired memory but no impairments in other areas of brain function, such as planning or attention, and no significant problems in everyday living.

Complaints of memory loss are extremely common, and probably occur in most people at some point during their life - particularly as they get older. However, the vast majority of people with such complaints still perform adequately on tests of memory and, therefore, cannot be described as having MCI.

How many people with MCI develop dementia?

People who have MCI are at an increased risk of going on to develop Alzheimer's disease (or another form of dementia). In studies carried out in memory clinics, 10-15 per cent of people with MCI went on to develop dementia in each year that the research results were followed up. In community studies and clinical trials the rates are about half this level, but still represent a significantly increased level of risk. It is therefore very important to identify people with MCI, as they may be in the very early stages of the disease and more likely to benefit from early treatment in the future. However, many people with MCI improve or remain stable, and, therefore, do not develop dementia.
Can we identify the people with MCI who will go on to develop dementia?

A lot of research has focused upon techniques to try to improve ways of identifying people with MCI who will go on to develop Alzheimer's disease. Researchers have tried to do this by using different types of brain scans and detailed neuropsychological tests and by measuring the concentration of specific proteins in the spinal fluid. Some of these techniques show promise, and some are beginning to be introduced into routine clinical practice by doctors. This is, however, an area of ongoing research. So far, none of the techniques available are sufficiently developed to provide a definitive diagnosis in patients with MCI.

Treatments

There is some evidence that people with MCI are helped by treatments that have symptomatic benefit in mild to moderate Alzheimer's disease such as Aricept (trade name for Alzheimer's drug donepezil hydrochloride), Exelon (trade name for rivastigmine) and Reminyl (trade name for galantamine). (See Factsheet 401, What is Alzheimer's disease or Factsheet 407, Drug treatments for Alzheimer's disease). However, initial studies suggest that their effect in MCI is limited, and they are not usually available on the NHS. A number of new treatments are currently being investigated with the hope they can prevent or delay dementia in patients with MCI. Although this area of research contains much promise, these treatments are still in their development phase and it remains to be seen whether they will be both safe and of benefit to patients.

How can we minimise the risk of MCI and dementia?

A number of research studies have suggested that our lifestyle can have an effect on our risk of developing dementia. Factors such as a low level of physical activity have been shown to be associated with an increased risk of developing dementia. Other studies have shown that physical exercise, travelling, doing odd jobs, knitting and doing crossword puzzles are all associated with a reduced risk of developing dementia. Leisure activities such as these may well help the brain to retain a reserve capacity that can delay the onset of dementia. Appropriate physical exercise can contribute to a healthy heart and brain.

Your local Alzheimer's Society branch will always be willing to talk to you and offer advice and information to support your needs.

For more information, Dementia Catalogue, our specialist dementia information resource, is available on the website at alzheimers.org.uk/dementiacatalogue

Factsheet 470

Last updated: September 2008
Last reviewed: September 2008

Reviewed by: Dr Nick Fox, Professor of Neurology and MRC Senior Clinical Fellow at the Institute of Neurology, University College London in the Dementia Research Centre.