The term MCI describes a set of symptoms, rather than a specific disease. A person with MCI has mild problems with one or more of the following:
- memory - for example, forgetting recent events or repeating the same question
- reasoning, planning or problem-solving - for example, struggling with thinking things through
- attention - for example, being very easily distracted
- language - for example, taking much longer than usual to find the right word for something
- visual depth perception - for example, struggling to interpret an object in three dimensions, judge distances or navigate stairs.
These symptoms will have been noticed by the individual, or by those who know them. For a person with MCI, these changes may cause them to experience minor problems or need a little help with more demanding daily tasks (eg paying bills, managing medication, driving). However, MCI does not cause major problems with everyday living. If there is a significant impact on everyday activities, this may suggest dementia.
Most healthy people experience a gradual decline in mental abilities as part of ageing. In someone with MCI, however, the decline in mental abilities is greater than in normal ageing. For example, it's common in normal ageing to have to pause to remember directions or to forget words occasionally, but it's not normal to become lost in familiar places or to forget the names of close family members.
If the person with MCI has seen a doctor and taken tests of mental abilities, their problems will also be shown by a low test score or by falling test scores over time. This decline in mental abilities is often caused by an underlying illness.