What is Mild Cognitive Impairment?
Mild Cognitive Impairment, or MCI, is an intermediate stage condition between normal cognitive functioning and Alzheimer’s disease or other types of dementia:
Signs of MCI include a “change in cognition” — this typically means memory problems, but it can also include planning and reasoning skills that could negatively affect higher function tasks like managing personal finances. Most people with MCI are able to continue to live independently.
Some (but not all) people diagnosed with MCI later decline into Alzheimer’s. Current research puts the probability of a person with MCI converting to Alzheimer’s at around 10% to 15% per year. Amnestic MCI, a subtype characterized by subtle but noticeable memory loss, is the most common type of MCI that can lead to Alzheimer’s.
Since MCI is a transitional stage condition that may (or may not) continue on to Alzheimer’s or another form of dementia, there isn’t one simple test that can be used to diagnose MCI. However, one of the best methods to detect a change in cognitive functioning is through routine, annual health screenings.
For example, if Patient A & Patient B take the same cognitive screening test for several years, the resulting chart could look like:
Cognitive Screening Example: Baseline Test + Annual Tests
The first year establishes each patient’s baseline performance, which is then used to compare subsequent retests (both patients score within the normal range in this example). They are then retested for five additional years.
The significant decline in Patient A’s screening test results in years 4-6 would likely trigger additional diagnostic tests to determine the cause of this decline. In some cases, cognitive decline in older adults can be caused potentially reversible conditions such as a Vitamin B-12 deficiency. Being able to view the historical trend in a patient’s cognitive screening results allows for a more timely medical intervention and treatment.
There are several paper-based cognitive screening tests available, along with newer computer-based (or tablet) cognitive testing tools as well. In 2011, Medicare launched a preventive health initiative known as the Annual Wellness Visit (AWV), which is meant as a health screening visit. The AWV includes detection of cognitive impairment as a screening service.
Looking into the future, there are some interesting experimental imaging tests, blood tests and spinal fluid tests that could be helpful in diagnosing MCI and predicting the chances of converting to Alzheimer’s. However, the National Institute on Aging recommends against biomarker testing for MCI and Alzheimer’s in general practice offices (primary care) until several important reliability issues have been resolved.