What does it mean to have a mild cognitive impairment diagnosis?

(Chapter 1 Symptoms and Diagnosis in my book)

In 2005 I was told that a diagnosis of MCI means that someone does not have dementia but their brain doesn't function like most people their age. I think that a lot of the symptoms are very similar to dementia. People with mild cognitive impairment and dementia can have short term memory problems, the fog and word finding problems. I have MCI but I experience the fog similar to someone who has dementia. Dementia will definitely progress, but with MCI some patients actually improve. That can't happen with dementia. With dementia the brain is shrinking and with MCI it is not.