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Mild Cognitive Impairment
Early Cognitive Decline is Dramatically Underdiagnosed
Over 90% of Americans expected to have mild cognitive decline are undiagnosed.
Posted December 8, 2023 Reviewed by Monica Vilhauer
An alarming new study from the University of Southern California estimates that over 90 percent of the 8 million Americans expected to have mild cognitive decline remain undiagnosed. Changes to the brain are natural as we age, which often makes it difficult to spot signs of cognitive decline in older adults.
Mild cognitive impairment (MCI) is a condition in which someone has minor problems with cognition and abilities, such as memory or thinking. These difficulties are worse than expected for a healthy person of their age. The difference between MCI and dementia is a person’s ability to function and take care of their basic needs. Socioeconomic and clinical factors influence the prevalence of MCI. People with cardiovascular disease, diabetes, hypertension and other health issues are at higher risk of cognitive decline, including dementia.
Neurodegenerative diseases like Alzheimer’s and Parkinson’s often first arise as clusters of symptoms that qualify as mild cognitive impairment. About one-third of adults diagnosed with MCI will develop dementia due to Alzheimer’s within five years. As new amyloid-targeting drugs such as lecanemab and donanemab for Alzheimer's emerge, timely detection of early-stage disease is more important than ever, as treatment is not indicated for later stages. Amyloid plaques kill brain cells, which can’t grow back. Catching diseases like Alzheimer's at their earliest stage can significantly increase the success of treatments.
The researchers analyzed data from 40 million Medicare beneficiaries aged 65 and older and compared the proportion diagnosed with the expected rate in this age group. They found that fewer than 8 percent of expected cases were actually diagnosed. Of the 8 million individuals predicted to have MCI based on their demographic profile, which includes age and gender, about 7.4 million were undiagnosed. An additional study by the same researchers found that out of 200,000 primary care physicians surveyed, all of whom see patients 65 and older, 99 percent are underdiagnosing MCI.
Diagnosing MCI can be challenging for several reasons. Neurological decline can be a significant source of shame or embarrassment for older adults, who may go out of their way to compensate for symptoms to avoid detection by family members and clinical evaluation. Symptoms are inconsistent and may present as memory lapses in one patient and decision-making and information-processing issues in another.
The condition is not well defined and is often used as an umbrella term for a group of symptoms that can stem from many different causes. This makes it difficult to educate family members and other loved ones on what warning signs to look for. Even if family members recognize the symptoms, it can be a challenging and highly sensitive conversation, and the person may resist treatment or further intervention. Access to memory care specialists, geriatricians, neurologists, or neuropsychologists can also create barriers.
However, if a patient does arrive at their primary care doctor with concerns about their mental cognition, there are a few relatively brief tests the physician can perform to screen for MCI. These include but are not limited to the Short Test of Mental Status, the Montreal Cognitive Assessment (MoCA) or the Mini-Mental State Examination (MMSE).
The physician can also perform a brief neurological exam and detect signs of Parkinson's disease, strokes, and tumors and perform bloodwork to help rule out physical problems that may affect memory, including a lack of vitamin B-12 or thyroid hormone. However, overscheduling and the 15-minute timeslots that insurance allows often limit primary care doctors. If a patient does not specifically schedule an appointment to discuss cognitive concerns and makes offhand comments about cognition or memory towards the end of a routine appointment, it can be difficult to begin a sensitive conversation and testing with such time restraints.
We need to begin addressing these barriers that cause such low detection of MCI and raise awareness of the condition. Underdiagnosis of MCI in older populations not only impacts patients’ quality of life but could prevent them from accessing new Alzheimer’s treatments that may be able to slow cognitive decline if it’s caught soon enough.
