What’s the Difference Between Mild Cognitive Impairment (MCI) and Dementia?

As a neuropsychologist, I often see patients who are concerned about the possibility that they have Alzheimer's disease. When we discuss their test results and diagnosis, I often get questions such as “what's the difference between Alzheimer's disease and dementia?” Or “what's the difference between mild cognitive impairment and dementia?”

Both mild cognitive impairment (MCI) and dementia are umbrella terms, meaning that they are broad or general ways of defining a condition that can have many different, specific causes.

How are they similar?

Both MCI and dementia involve having cognitive skills that are not normal for age. For many people, this is memory impairment. But, other people have difficulty with language functioning, thinking speed, visuospatial skills, problem-solving, or attention. Both MCI and dementia are diagnosed through a series of medical and cognitive evaluations, typically including: bloodwork, brain imaging (such as CT or MRI), neuropsychological evaluation, and a careful history-taking to rule out other causes of thinking difficulty by a physician, psychologist, or both.

Both MCI and dementia can be caused by the following:

• Alzheimer’s disease
• Cerebrovascular disease (including stroke)
• Parkinson’s disease
• Lewy Body disease
• Frontotemporal degeneration

How are they different?

The main difference between MCI and dementia comes down to how folks are functioning in day-to-day tasks. People with MCI are still pretty independent with their daily functioning. They usually are still driving, cooking, paying bills, and taking care of the house. Some are even still working. They may use systems, strategies, or other aides (like a pill organizer) to keep themselves independent.

People with dementia, on the other hand, have cognitive difficulties that have progressed to the point that they interfere with the person being able to be independent in her daily life. Therefore, they may have family members or healthcare assistance who administer their medications to them, do the cooking, and/or provide transportation. A person with dementia typically would not be able to hold down a job.

In addition, people with MCI may have only one area of thinking difficulty (often memory), with normal thinking abilities in other domains. People with dementia usually have global cognitive impairment or problems in multiple cognitive domains.

Chime in - how could healthcare professionals do a better job of explaining the difference between MCI and dementia when providing the initial diagnosis?