Brief Cognitive Tests Used in Primary Care Cannot Accurately Differentiate Mild Cognitive Impairment from Subjective...

Area of Science:

• Neurology
• Cognitive Science
• Geriatrics

Background:

• Distinguishing mild cognitive impairment (MCI) from subjective cognitive decline (SCD) is critical due to MCI's higher progression rate to dementia.
• Accurate differentiation is essential for timely intervention and eligibility for future disease-modifying therapies indicated at the MCI stage.

Purpose of the Study:

• To evaluate the accuracy of the Mini-Mental State Examination (MMSE), clock-drawing test (CDT), and Attention/Executive Functioning Questionnaire (AQT) in differentiating MCI from SCD.
• To assess the efficacy of single tests and combinations of these cognitive assessments in a primary care setting.

Main Methods:

• A cohort of 466 non-demented patients with cognitive complaints, referred to memory clinics, were classified as MCI (n=258) or SCD (n=208).
• The diagnostic accuracy of MMSE, CDT, and AQT was assessed individually and in combination using training and validation samples.

Main Results:

• The MMSE demonstrated the highest accuracy as a single test (sensitivity 73%, specificity 60%).
• The combination of MMSE < 27 or AQT > 91 seconds showed improved specificity (78%) but not significantly better overall accuracy (AUC 0.76) compared to MMSE alone (AUC 0.75).
• CDT and AQT performed significantly worse than MMSE, with no significant improvements noted for any combination of two or three tests.

Conclusions:

• Current cognitive screening tests, including MMSE, CDT, and AQT, lack sufficient accuracy to reliably differentiate MCI from SCD in individuals seeking medical attention for cognitive symptoms.
• There is a significant need for the development and validation of more accurate screening tools for primary care to enhance the early identification of MCI.