Takeaway
Cognitive and behavioral decline begin around 20 years before diagnosis of incident mild cognitive impairment (MCI).
Why this matters
Mild cognitive impairment (MCI) is often recognized as the earliest symptom of neurodegeneration in dementia and Alzheimer’s disease (AD).
Clarification of the timeline of MCI is important as early diagnosis and intervention could slow or even prevent further cognitive decline and progression of dementia and death.