Mild cognitive impairment (MCI) is a condition in which individuals demonstrate cognitive impairment with minimal impairment of instrumental activities of daily living (IADL)"

Source : Neurology. 2018 Jan 16; 90(3): 126–135.

It can occur as a transitional stage between 'normal' ageing (withAge-related memory declineplugin-autotooltip__plain plugin-autotooltip_bigAge-related memory decline

"Normal aging is associated with a decline in various memory abilities in many cognitive tasks; the phenomenon is known as age-related memory impairment (AMI) or age-associated memory impairment (AAMI). The ability to encode new memories of events or facts and working memory shows decline in both cross-sectional and longitudinal studies.) and the development of dementia orAlzheimer's diseaseplugin-autotooltip__plain plugin-autotooltip_bigAlzheimer's disease

"Alzheimer’s disease is a chronic progressive neuro-degenerative disorder characterised by three primary groups of symptoms. The first group (cognitive dysfunction) includes memory loss, language difficulties, and executive dysfunction (that is, loss of higher level planning and intellectual coordination skills). The second group comprises psychiatric symptoms and behavioural disturbances — for example, depression, hallucinations, delusions, agitation — collectively termed …

It can involve some cognitive impairment and mild memory loss.

It was first recognised as a distinct condition around two decades ago. The incidence is currently estimated at between 10% and 25% of the over 60s.

Its cause is unknown and there are currently no effective treatments.

Note: There is currently a proposal to re-name MCI to Mild Neurocognitive Disorder