Mild Cognitive Impairment (MCI)

What MCI looks like

People with MCI might:

• forget appointments, recent conversations or events more often than before
• lose their train of thought or the thread of conversations
• have more trouble finding words
• find complex tasks, planning or decisions harder
• get lost in less familiar places
• take longer to do familiar tasks, but still complete them

They usually still manage daily activities, perhaps with more effort, lists or reminders. In dementia, problems are severe enough to interfere with independence.

Normal aging vs MCI vs dementia

Types of MCI

• Amnestic MCI: mainly memory problems. More likely to progress to Alzheimer's disease.
• Non-amnestic MCI: problems with attention, language, planning or visual-spatial skills, with memory relatively preserved. May progress to other dementias such as Lewy body dementia or frontotemporal dementia.

Causes and risk factors

Neurodegenerative and vascular causes

• early Alzheimer's disease
• vascular cognitive impairment from small strokes or blood vessel disease, see vascular dementia
• Lewy body disease, Parkinson's disease

Potentially reversible causes

• depression and anxiety
• medicine side effects, especially sedatives, sleep aids, anticholinergics (some bladder and allergy medicines) and opioids
• vitamin B12 deficiency
• hypothyroidism
• sleep apnea and poor sleep
• heavy alcohol use
• hearing and vision loss

Risk factors

Age, family history, APOE e4 gene, high blood pressure, diabetes, high cholesterol, smoking, obesity, physical inactivity, low education, social isolation, hearing loss and previous head injury.

Diagnosis

A primary care doctor, geriatrician or neurologist will:

1. Take a history from the person and someone who knows them well.
2. Do cognitive screening such as the MoCA or Mini-Cog, followed by detailed neuropsychological testing if needed.
3. Review medicines and alcohol use.
4. Check blood tests: vitamin B12, thyroid, blood count, metabolic panel, and others as indicated.
5. Screen for depression and sleep problems; consider a sleep study.
6. Order brain imaging (MRI or CT) to look for strokes, tumors or other causes.
7. Biomarker tests (amyloid PET, spinal fluid or blood tests) when considering Alzheimer's-specific treatment.

Treatment and what helps

There is no medicine specifically approved for MCI in general. Cholinesterase inhibitors used for Alzheimer's have not been shown to prevent progression from MCI. For people with MCI due to Alzheimer's disease confirmed by biomarkers, anti-amyloid antibody treatments (lecanemab, donanemab) may be options to modestly slow decline; specialists assess eligibility.

Evidence-based steps:

• Treat reversible causes such as B12 deficiency, thyroid disease, depression and sleep apnea.
• Review medicines that can impair thinking.
• Exercise regularly: the American Academy of Neurology recommends regular exercise, such as twice a week, for people with MCI.
• Control blood pressure, blood sugar and cholesterol.
• Use hearing aids if hearing is reduced.
• Stay mentally and socially active.
• Use memory aids: calendars, phone reminders, pill organizers.
• Plan ahead: legal and financial planning while decisions are easy.

Outlook

Each year, about 10 to 15% of people with MCI progress to dementia, compared with 1 to 2% of people the same age without MCI. Many remain stable for years, and some, particularly when a reversible cause is treated, return to normal. Regular reassessment, usually every 6 to 12 months, tracks changes.

Frequently asked questions

What is mild cognitive impairment?

MCI is a noticeable decline in memory or thinking that is greater than normal for age and shows on tests, but does not significantly interfere with independence in daily life. It is a stage between normal aging and dementia.

Does MCI always turn into dementia?

No. About 10 to 15% of people with MCI progress to dementia each year. Many remain stable, and some improve, especially if a reversible cause such as depression, medicine side effects or vitamin deficiency is treated.

What is the difference between MCI and dementia?

In MCI, memory or thinking problems are noticeable and measurable but people still manage daily life largely independently. In dementia, the problems are severe enough to interfere with independence, such as managing money, medicines or self-care.

Can MCI be treated?

There is no cure, but treating reversible causes, regular exercise, controlling blood pressure and diabetes, hearing aids and staying socially active can help. For MCI due to Alzheimer's disease, newer antibody medicines may modestly slow decline in eligible people.