Mild Cognitive Impairment: Signs, Causes and What Helps

Mild cognitive impairment, or MCI, is a noticeable decline in memory or other thinking skills that goes beyond normal aging but is not severe enough to be dementia. The person and their family can see the change, yet the person still handles most everyday activities on their own.

The Alzheimer's Association describes MCI as an early stage of memory loss or of other thinking skills, such as language or visual and spatial perception. Cleveland Clinic places it between typical thinking and dementia, and notes that some cases progress to dementia but not all do.

It is common. The Alzheimer's Association estimates that about 12 to 18 percent of people aged 60 or older have MCI. A 2018 guideline from the American Academy of Neurology found it rises steeply with age: 6.7 percent at ages 60 to 64, 10.1 percent at 70 to 74 and 25.2 percent at 80 to 84. The academy retired that guideline in February 2024, so treat its figures as a 2018 summary of the evidence.

Doctors describe two broad types. Amnestic MCI mainly affects memory: forgetting appointments, conversations or recent events the person would once have recalled easily. Non-amnestic MCI mainly affects other thinking skills. The Alzheimer's Association lists sound decision making, judging the time or sequence of steps needed for a complex task, and visual perception.

Cleveland Clinic lists the everyday signs: being easily distracted, trouble finding words, misplacing items, and missing bills or dates. The changes can touch attention, judgment, language, memory, planning and reasoning. Occasionally there are movement problems or a reduced sense of smell.

At home it often looks small. The same question asked twice in one visit, a missed appointment, a late notice on a bill that was always paid on time, a favorite recipe that suddenly feels like hard work. One slip means little. A new pattern that keeps repeating is worth raising with a doctor.

Normal aging: the Alzheimer's Association gives examples of typical age-related change. Sometimes forgetting names or appointments but remembering them later. Making occasional errors with household bills. Sometimes having trouble finding the right word. Misplacing things from time to time and retracing steps to find them.

MCI: the changes are greater than expected for the person's age and are noticeable to the person and to the people around them. Daily independence is largely kept. They may lean on lists, calendars and extra time, but they still cook, pay bills and get to appointments.

Dementia: the decline is now serious enough to disrupt daily life. In the Alzheimer's Association's warning signs, memory loss disrupts daily routines, familiar tasks become difficult and judgment slips in ways that put safety or money at risk. The person increasingly needs help to live day to day.

A simple way to hold the difference: in normal aging, the person forgets and later remembers. In MCI, others notice a real change but independence holds. In dementia, the changes start to take independence away. Only a clinician can say which one is happening.

The causes are not fully understood. The Alzheimer's Association says many cases, but not all, are thought to come from very early brain changes of Alzheimer's or another neurodegenerative disease. The strongest risk factors are older age, a family history of dementia and conditions that raise cardiovascular risk. Cleveland Clinic adds the APOE e4 gene variant.

Some contributors can be treated. Cleveland Clinic lists sleep apnea, depression and anxiety, an underactive thyroid, vitamin B12 deficiency, dehydration, urinary tract infections, and diabetes or high blood pressure as conditions that may play a part.

Medicines matter too. Cleveland Clinic names antihistamines, antidepressants, some blood pressure medicines, antiseizure drugs, benzodiazepines, muscle relaxants and opiates. The Alzheimer's Association warns that some medications cause thinking problems that are mistakenly diagnosed as MCI. Never stop a medicine on your own: bring a full list, including over the counter sleep aids, to the doctor.

Hearing is worth checking. In the ACHIEVE trial, published in The Lancet in 2023, hearing aids and counseling did not slow cognitive decline across all 977 adults aged 70 to 84 with hearing loss. In one group at higher risk of decline, though, they were linked to 48 percent less decline over three years.

There is no single test. MCI is a clinical diagnosis based on a doctor's judgment. The Alzheimer's Association describes the usual workup: a medical and family history, an assessment of daily function with input from a family member or friend, brief mental status tests, a neurological exam, a mood evaluation because depression can mimic MCI, and blood tests and brain imaging.

A common brief test is the Montreal Cognitive Assessment, or MoCA. It is scored out of 30 and covers memory, attention, language, orientation, abstraction and more complex tasks such as executive function. A 2015 study in BMC Geriatrics found it spread people with MCI across a wider range of scores than the older Mini-Mental State Examination, making early change easier to see.

Cleveland Clinic lists other possible steps: blood and urine tests, a CT or MRI scan, a lumbar puncture and detailed neuropsychological testing. Blood tests are where problems such as low B12 or thyroid trouble show up.

Biomarkers are increasingly part of the picture. A person with MCI who has an abnormal amyloid PET scan or spinal fluid test is considered to have MCI due to Alzheimer's disease. Revised guidelines from the Alzheimer's Association and the National Institute on Aging recommend biomarkers in the brain, spinal fluid or blood to assess who is at high risk.

Not always. The Alzheimer's Association estimates that 10 to 15 percent of people with MCI develop dementia each year, and that about one third of people with MCI due to Alzheimer's develop dementia within five years. The AAN guideline found that 14.9 percent of people with MCI over 65 developed dementia within two years.

Some people stay the same and some get better. Across the studies the AAN reviewed, between 14.4 and 55.6 percent of people with MCI returned to normal thinking, although some of them later developed dementia. Cleveland Clinic notes that when a treatable cause is found, memory and thinking may return to normal for the person's age.

Because the course varies so much, follow-up matters. The Alzheimer's Association recommends re-evaluation every six months, and Cleveland Clinic says follow-up visits are typically every six to 12 months.

The AAN guideline recommended regular exercise, twice a week, as part of managing MCI. It also told clinicians to look for modifiable risk factors, to wean people off medicines that may worsen thinking where that is safe, and said cognitive training may be recommended. It found no good evidence for prescribing dementia drugs called cholinesterase inhibitors in MCI.

Cleveland Clinic's list of treatments follows the cause: adjusting medicines, treating depression, sleep apnea or a vitamin deficiency, reducing risk factors such as high blood pressure and diabetes, and brain-stimulating activities. Keeping up friendships, clubs, volunteering and hobbies is a practical way to keep days full and the mind busy.

For MCI due to Alzheimer's, two newer drugs exist. The FDA gave lecanemab (Leqembi) traditional approval in July 2023 and approved donanemab (Kisunla) in 2024, each to be started at the MCI or mild dementia stage of Alzheimer's disease. Kisunla carries a boxed warning for amyloid-related imaging abnormalities, called ARIA. Whether either fits is a conversation for a neurologist.

Routines do a lot of the remembering. Keep keys, glasses and phone in one fixed spot. Put a large calendar or whiteboard where it is seen every morning. A short weekly planning chat about appointments, bills and plans keeps everyone on the same page without taking over.

Make medicines simple: a weekly pill organizer, pharmacy blister packs or phone alarms, and one up to date list of every prescription and supplement. Money needs quiet safeguards too: automatic bill payments, bank alerts for large withdrawals, and view-only account access for a family member the person chooses.

Plan while the person can take part. The Alzheimer's Association says putting financial and legal plans in place early lets the person express their wishes. That usually means a financial power of attorney, a health care power of attorney and a living will. An elder law attorney can explain the rules in your state.

Check driving before there is a scare. The Alzheimer's Association suggests a comprehensive driving evaluation by an occupational therapy driving rehabilitation specialist. Warning signs include getting lost in familiar places, missing traffic signs, errors at intersections and hitting curbs.

Most people with MCI do not need a caregiver. A few hours a week can still help when the person lives alone and is missing meals or medicines, when a spouse needs regular time off, when driving has stopped and errands are piling up, or when family lives far away and wants someone to notice changes early.

Non-medical companion care fits this stage well: conversation, walks, help keeping the calendar, medicine reminders, meal preparation, light housekeeping and company on trips to appointments or the shops. It does not include medical care such as nursing or injections.

If that sounds useful, Dementia In Home sends 3 to 5 video profiles of caregivers with dementia experience within 48 hours, free. Call (689) 333-6079.