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Increasing Inaccuracy of Self-Reported Subjective Cognitive Complaints Over 24 Months in Empirically Derived Subtypes of Mild Cognitive Impairment
Published online by Cambridge University Press: 02 October 2018
Abstract
Objectives: Although subjective cognitive complaints (SCC) are an integral component of the diagnostic criteria for mild cognitive impairment (MCI), previous findings indicate they may not accurately reflect cognitive ability. Within the Alzheimer’s Disease Neuroimaging Initiative, we investigated longitudinal change in the discrepancy between self- and informant-reported SCC across empirically derived subtypes of MCI and normal control (NC) participants. Methods: Data were obtained for 353 MCI participants and 122 “robust” NC participants. Participants were classified into three subtypes at baseline via cluster analysis: amnestic MCI, mixed MCI, and cluster-derived normal (CDN), a presumptive false-positive group who performed within normal limits on neuropsychological testing. SCC at baseline and two annual follow-up visits were assessed via the Everyday Cognition Questionnaire (ECog), and discrepancy scores between self- and informant-report were calculated. Analysis of change was conducted using analysis of covariance. Results: The amnestic and mixed MCI subtypes demonstrated increasing ECog discrepancy scores over time. This was driven by an increase in informant-reported SCC, which corresponded to participants’ objective cognitive decline, despite stable self-reported SCC. Increasing unawareness was associated with cerebrospinal fluid Alzheimer’s disease biomarker positivity and progression to Alzheimer’s disease. In contrast, CDN and NC groups over-reported cognitive difficulty and demonstrated normal cognition at all time points. Conclusions: MCI participants’ discrepancy scores indicate progressive underappreciation of their evolving cognitive deficits. Consistent over-reporting in the CDN and NC groups despite normal objective cognition suggests that self-reported SCC do not predict impending cognitive decline. Results demonstrate that self-reported SCC become increasingly misleading as objective cognitive impairment becomes more pronounced. (JINS, 2018, 24, 842–853)
Keywords
- Type
- Regular Research
- Information
- Journal of the International Neuropsychological Society , Volume 24 , Issue 8 , September 2018 , pp. 842 - 853
- Copyright
- Copyright © The International Neuropsychological Society 2018
Footnotes
Data used in preparation of this article were obtained from the Alzheimer’s Disease Neuroimaging Initiative (ADNI) database (http://adni.loni.usc.edu). As such, the investigators within the ADNI contributed to the design and implementation of the ADNI and/or provided data but did not participate in analysis or writing of this article. A complete listing of ADNI investigators can be found at http://adni.loni.usc.edu/wp-content/uploads/how_to_apply/ADNI_Acknowledgement_List.pdf. Conflict of Interest Disclosures: Dr. Bondi is a consulting editor for the Journal of the International Neuropsychological Society, serves as a consultant for Eisai, Novartis, and Roche, and receives royalties from Oxford University Press. Dr. Galasko serves as editor for Alzheimer’s Research and Therapy, and as a paid consultant on Data Safety Monitoring Boards for Pfizer, Inc., Elan, Inc., and Balance Pharmaceuticals, Inc. Dr. Salmon serves as a paid consultant for Takeda Pharmaceuticals. The other authors report no disclosures.
References
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