Mild Cognitive Impairment (MCI) is a condition consisting in a slight decline in memory and thinking ability, which exceeds the level expected due to normal ageing. It is considered as the stage between normal ageing and dementia
Cognition is a term that refers to mental processes or actions that make possible everyday life. Normally, these mental processes worsen with age.1 However, people with Mild Cognitive Impairment (MCI) experience noticeable changes or difficulties in these skills at a greater rate compared with people of the same age, without MCI.2
For example, occasionally forgetting words and misplacing things are commons sign of normal ageing; people with MCI may forget the names of close family members, forget what they have done recently or what they are planning to do in the future, such as remembering appointment dates 1

So, the term Mild Cognitive Impairment and its abbreviation, MCI, are used to describe a medical condition consisting in minor difficulties in attention, language, reasoning, thinking and memory.1 However, these difficulties are not severe enough to significantly impact normal life. Everyday activities such as working, and socialising can be done with minimal help (2–4) in contrast to Alzheimer’s disease or other types of dementia
Read more about what MCI signs and symptoms are.
References
1. Alzheimer’s Society. Factsheet 470LP. 2015. Available at: https://www.alzheimers.org.uk/sites/default/files/2019-09/470lp-what-is-mild-cognitive-impairment-mci-190521.pdf
2. Monastero R, et al. J Alzheimers Dis 2009;18:11–30
3. Petersen RC, et al. Int Psychogeriatr 1997;9(Suppl. 1):65–69
4. Alzheimer’s Disease International. World Alzheimer Report 2018. Available at: https://www.alz.co.uk/research/WorldAlzheimerReport2018.pdf