What is Mild Cognitive Impairment?

June 19, 2025

Science Updates, Care & Treatment , News, Brain Health Awareness

Earlier this month, UW MBWC's Justin Miller presented the latest on brain health and aging in a webinar hosted by the AARP, alongside other experts. He discussed the distinctions between normal aging, mild cognitive impairment (MCI), and dementia. He clarified some of the biggest questions on the minds of community members, such as, What is MCI? And how is it different from normal age-related declines?

As we age, we may notice it becomes harder to remember names or where we put our keys. With public awareness of brain aging and Alzheimer's disease risk growing, it’s understandable for adults to wonder whether moments of forgetfulness could be signs of something more serious.

 

What is Mild Cognitive Impairment (MCI)?

  • Mild Cognitive Impairment, or MCI for short, is a medical diagnosis for symptoms of memory loss and trouble with language and judgment that don't affect daily activities. For some people, MCI is the in-between stage between typical aging and dementia. A neuropsychologist can determine a diagnosis of MCI if they find evidence of a decline on tests of memory and thinking compared to people of the same age and education level. People living with MCI are fully independent in their everyday lives, though they may need to use more effort or find new strategies to finish tasks. Dr. Miller says that someone with MCI will still be able to cook for themselves, clean the house, and take their medications properly.

 

  • But MCI does not always progress to dementia.  Approximately 25% of MCI cases revert to normal cognition. Dr. Miller explained that MCI can occur when something is affecting a person's mental health or sleep patterns, such as depression, drug or alcohol misuse, or the side effects of medications. Treatment of these conditions can resolve the cognitive decline.

 

  • About 1/3 of people diagnosed with MCI progress to dementia within 5 years. "The biggest difference between MCI and dementia is that, in dementia, there are now impairments in daily functioning. In MCI, where you have impairments in memory or attention, those impairments have now reached a point where they are starting to cause problems in an individual's ability to carry out their daily activities," said Dr. Miller. For example, someone developing dementia might have trouble remembering their medications, appointments, or how to get home from the neighborhood grocery store. They may not feel safe in the kitchen, forget ingredients in familiar recipes, or have trouble with things that used to be automatic for them. Eventually, a person living with dementia relies on a caregiver in most activities of daily life.

 

What is the difference between 'Alzheimer's disease' and 'dementia'? 

alz.org

"A lot of people equate dementia, or think it's synoymous with, Alzheimer's disease, and that's not really the case," said Dr. Miller. "Dementia is an umbrella term for a specific clinical syndrome of signs and symptoms that we see in the clinic. The leading cause of dementia is indeed Alzheimer's disease. We also see vasular diseases and other rarer causes, such as Lewy bodies and frontotemporal degeneration."

Approximately 6.7 million Americans are living with symptoms of Alzheimer's disease. About 1 in 9 adults over the age of 65 has Alzheimer's disease, and this risk increases with age. Since 2018, deaths due to Alzheimer's disease have increased by 146%. Dr. Miller noted that these figures may underestimate the true prevalence, as they only include people who received formal diagnoses in medical clinics or research centers. Many people lack easy access to medical care and go undiagnosed.

 

Prevention - What Can You Do to Preserve Brain Health?

In terms of preventing dementia, Dr. Miller pointed to the findings of the 2024 Lancet Commission on dementia prevention, intervention and care, which estimates that up to 45% of cases of dementia worldwide may be preventable through addressing 14 modifiable risk factors. 

These risk factors include:

  • lower levels of education
  • hearing impairment
  • high blood pressure
  • smoking
  • obesity
  • hypertension and high cholesterol
  • depression
  • physical activity
  • diabetes
  • excessive alcohol consumption
  • traumatic brain injury
  • air pollution
  • social isolation

"From this report, the estimate is that up to 30% of your risk  for dementia can be reduced by pursuing lifestyle changes in midlife," said Dr. Miller. He also shared published findings that managing hypertension and high cholesterol, diabetes, and smoking have the greatest influence on reducing late-life risk for dementia.

 

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