Mild cognitive impairment goes undiagnosed in 7 Million Americans

Uncovering undiagnosed cognitive impairment in the U.S. Medicare population.


Many people may dismiss memory lapses and difficulty planning tasks as typical signs of getting older. However, these can be early signs of mild cognitive impairment (MCI), which might indicate the onset of Alzheimer’s disease. Unfortunately, most individuals with MCI are unaware of their condition, which prevents them from taking advantage of preventive measures and new treatments, including a recently approved Alzheimer’s drug that can slow its progression. 

Two new studies from USC Dornsife College of Letters, Arts, and Sciences reveal this concerning issue. One study analyzed data from 40 million Medicare beneficiaries aged 65 and older. They found that less than 8% of expected MCI cases were diagnosed. Of the 8 million predicted to have MCI based on demographics, approximately 7.4 million were undiagnosed. This highlights a significant gap in recognizing and addressing this condition.

Soeren Mattke, director of the Brain Health Observatory at USC Dornsife’s Center for Economic and Social Research, who led the investigations, said, “This study is meant to raise awareness of the problem. “We want to say, ‘Pay attention to early changes in cognition, and tell your doctor about them. Ask for an evaluation.’ We want to reach physicians to say, ‘There’s a measurable difference between aging and pathologic cognitive decline, and detecting the latter early might identify those patients who would benefit from recently approved Alzheimer’s treatments.”

Mild cognitive impairment (MCI) is influenced by factors like socioeconomics and existing health conditions. Those with heart problems, diabetes, high blood pressure, and other health issues are at a higher risk of cognitive decline, including dementia. These health problems are more common in historically disadvantaged groups.

The studies discovered that detecting MCI is even more complex in these groups, which is worrying because they already face a greater risk. In addition, the burden of the disease is higher in these populations. The second study involving 200,000 primary care clinicians found that 99% missed MCI cases. This means very few doctors can diagnose MCI early, which is crucial for the best treatment.

Unlike dementia, MCI doesn’t lead to disability. It causes occasional challenges in daily life but doesn’t result in severe cognitive impairment.

Mild cognitive impairment (MCI) can show up in different ways. The most common is forgetfulness. Another form affects how efficiently you do tasks, making things like managing finances or paying bills online harder. There’s also a behavioral form, where you might notice mild changes in your personality. Often, these forms coexist, meaning you could have a mix of these symptoms.

It’s important to know that MCI is about your cognitive abilities and isn’t a specific disease. Recent progress in treating the most common cause of MCI, Alzheimer’s disease, makes it urgent to improve MCI detection.

MCI might not be diagnosed for various reasons. People may need to realize they have a problem or may not talk about it. Doctors might miss subtle signs of difficulty or notice but not correctly record the diagnosis in a patient’s medical file. This leads to widespread underdiagnosis in the United States.

One key reason is that if planned explicitly, brain health is only typically discussed or assessed during regular clinical visits. Detecting cognitive problems is easy but only happens if it’s part of the plan.

Focusing on high-risk people through risk-based MCI detection could help find more cases. Using digital tests before a doctor’s visit could also identify cognitive issues earlier.

Early treatment is essential because the brain can’t fully recover once damage occurs. For MCI caused by Alzheimer’s disease, treating it as soon as possible leads to better outcomes, even though the disease progresses slowly. Every day matters in managing it.

The study reveals a substantial shortfall in recognizing mild cognitive impairment (MCI) within the U.S. population, particularly among those at higher risk based on their demographic characteristics. Timely identification of MCI is imperative for implementing early interventions, underscoring the pressing need to enhance early detection to prevent the development of severe cognitive impairments.

Journal reference:

  1. Mattke, S., Jun, H., Chen, E. et al. Expected and diagnosed rates of mild cognitive impairment and dementia in the U.S. Medicare population: observational analysis. Alzheimer’s Research Therapy. DOI: 10.1186/s13195-023-01272-z.
  2. Liu, Y., Jun, H., Becker, A. et al. Detection Rates of Mild Cognitive Impairment in Primary Care for the United States Medicare Population. Journal of Prevention of Alzheimer’s Disease. DOI: 10.14283/jpad.2023.131.
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