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

Abstract

Background: Differentiating mild cognitive impairment (MCI) from subjective cognitive decline (SCD) is important because of the higher progression rate to dementia for MCI and when considering future disease-modifying drugs that will have treatment indications at the MCI stage. Objective: We examined if the two most widely-used cognitive tests, the Mini-Mental State Examination (MMSE) and clock-drawing test (CDT), and a test of attention/executive function (AQT) accurately can differentiate MCI from SCD. Methods: We included 466 consecutively recruited non-demented patients with cognitive complaints from the BioFINDER study who had been referred to memory clinics, predominantly from primary care. They were classified as MCI (n = 258) or SCD (n = 208) after thorough neuropsychological assessments. The accuracy of MMSE, CDT, and AQT for identifying MCI was examined both in training and validation samples and in the whole population. Results: As a single test, MMSE had the highest accuracy (sensitivity 73%, specificity 60%). The best combination of two tests was MMSE < 27 points or AQT > 91 seconds (sensitivity 56%, specificity 78%), but in logistic regression models, their AUC (0.76) was not significantly better than MMSE alone (AUC 0.75). CDT and AQT performed significantly worse (AUC 0.71; p < 0.001-0.05); otherwise no differences were seen between any combination of two or three tests. Conclusion: Neither single nor combinations of tests could differentiate MCI from SCD with adequately high accuracy. There is a great need to further develop, validate, and implement accurate screening-tests for primary care to improve accurate identification of MCI among individuals that seek medical care due to cognitive symptoms.

Consistency and applicability of different brief screen instrument of cognitive function in elderly population

“…As previously reported, MMSE usually had more accuracy compared to other tools, however still with limitations. For example, MMSE had the highest accuracy when assessing MCI but still could not differentiate MCI from subjective cognitive decline (SCD) [ 44 ]. In addition, systematic review identified numerous studies using MMSE as assessment tool for dementia in elderly but a summary diagnostic accuracy could not be estimated due to various cut points and dementia types [ 45 ].…”

Individualized prognosis of cognitive decline and dementia in mild cognitive impairment based on plasma biomarker combinations

“…The patients were recruited and evaluated at memory clinics in the cities of Lund, Malmö and Ängelholm between July 2008 and June 2019. They were between 60 and 80 years old and fulfilled the consensus criteria for MCI suggested by Petersen 28 (including: cognitive complaints, preferably corroborated by an informant; objective cognitive impairment, adjusted for age and education; preservation of general cognitive functioning and an MMSE score of 24-30; and no or minimal impairment of daily life activities) but did not fulfill criteria for dementia, as described previously in detail 29 . Exclusion criteria included cognitive impairment that could better be accounted for by another non-neurodegenerative condition, severe somatic disease and current alcohol or substance abuse.…”

Prediction of future Alzheimer’s disease dementia using plasma phospho-tau combined with other accessible measures

“…And even if a unified definition and set of cognitive tests were determined, the comprehensive cognitive test battery needed would not fit the testing routines in e.g. primary care 38.…”