Reversion From Mild Cognitive Impairment To Normal Cognition: False-Positive Error Or True Restoration Thanks To Cognitive Control Ability?

Abstract

Purpose

Relatively little attention has been paid to the meaning of reversion from mild cognitive impairment (MCI) to cognitively normal (CN), compared to MCI progression studies. The purpose of the study was to investigate the characteristics contributing to reversion from MCI to CN and to identify the associated factors with such reversion.

Patients and methods

We retrospectively identified 200 individuals who initially diagnosed as MCI and completed the second visit from the National Research Center for Dementia (NRCD) registry in Korea. Participants underwent comprehensive clinical and neuropsychological assessments. Factors associated with reversion were examined by a independent-samples t-test, χ² test, and logistic regression. Longitudinal change was examined by a repeated measures analysis of variance (rANOVA).

Results

Based on the second assessment, 78 (39%) individuals were found to have reverted to CN (rMCI) and 118 (59%) remained with MCI (sMCI). Four (2%) progressed to Alzheimer’s disease dementia and they were excluded from further analysis. Over a wide range of socio-demographic, clinical, and neuropsychological variables, group difference was significant only in neuropsychological tests of cognitive control. Both groups showed improvement in several neuropsychological tests, implying a practice effect, but the rMCI group showed greater improvement.

Conclusion

Reversion from MCI to CN might not be a false-positive error but a true recovery from cognitive impairment. Our results suggest that cognitive control ability may be a characteristic favorable for the restoration of cognitive function. Therefore, assessment of cognitive control might facilitate the development of appropriate interventions for MCI as well as prognosis evaluation.

Keywords:

• mild cognitive impairment
• reversion
• cognitive control
• Alzheimer disease

Acknowledgments

This research was supported by a Basic Science Research Program through the National Research Foundation (NRF) of Korea, funded by the Ministry of Education (NRF-2017R1D1A1B03028377); the Bio & Medical Technology Development Program of the NRF funded by the Korean government (MSIT) (No. 2016M3A9E9941914); and the Brain Research Program through the NRF funded by the Ministry of Science, ICT & Future Planning (NRF-2014M3C7A1046041).

Author Contributions

HK and EHS designed the study and EHS wrote the study protocol. JYC, HJY, and EHS wrote the draft of the manuscript and undertook the statistical analyses. JYC, HK, KYC, JJL, KHL, and EHS collected and analyzed the data. All authors contributed toward data analysis, critically revised the paper, gave final approval of the version to be published, and agreed to be accountable for all aspects of the work.

Disclosure

The authors report no conflicts of interest in this work.