Stage-Dependent Significance of Subjective Memory Complaints: Responding to the Worried Well … and to the Unworried Unwell

Abstract

Sometimes, the worried well have reason to worry. As we learn more about the earlier and milder stages of neurocognitive disorders, converging evidence demonstrates that subjective memory complaints (SMCs) are to be taken seriously even in the absence of significant objective impairment as detected by standard neuropsychological tests. Some 17% of older adults with no objective deficits reported SMCs in one meta-analysis. 1 Mitchell A.J. The clinical significance of subjective memory complaints in the diagnosis of mild cognitive impairment and dementia: a meta-analysis. Int J Geriatr Psychiatry. 2008; 11: 1191-1202 Crossref Scopus (176) Google Scholar SMCs are associated not only with subjective distress and greater difficulties with activities of daily living, 2 Mitchell A.J. Beaumont H. Ferguson D. et al. Risk of dementia and mild cognitive impairment in older people with subjective memory complaints: meta-analysis. Acta Psychiatr Scand. 2014; 130: 439-451 Crossref PubMed Scopus (587) Google Scholar but also with neuropsychological and biologic markers of heightened risk for progression to dementia, including cerebrospinal fluid biomarkers associated with Alzheimer disease, 3 Mandecka M. Budziszewska M. Barczak A. et al. Association between cerebrospinal fluid biomarkers for Alzheimer's disease, APOE genotypes and auditory verbal learning task in subjective cognitive decline, mild cognitive impairment, and Alzheimer's disease. J Alzheimers Dis. 2016; 54: 157-168 Crossref PubMed Scopus (20) Google Scholar and brain changes, including increased fractional anisotropy, 4 Li X.Y. Tang Z.C. Sun Y. et al. White matter degeneration in subjective cognitive decline: a diffusion tensor imaging study. Oncotarget. 2016; 7: 54405-54414 Crossref PubMed Scopus (38) Google Scholar hippocampal atrophy, 5 Van Norden A.G. Fick W.F. de Laat K.F. et al. Subjective cognitive failures and hippocampal volume in elderly with white matter lesions. Neurology. 2008; 71: 1152-1159 Crossref PubMed Scopus (84) Google Scholar quantitative electroencephalographic alterations, 6 Ferreira D. Jelic V. Cavallin L. et al. Electroencephalography is a good complement to currently established dementia biomarkers. Dement Geriatr Cogn Disord. 2016; 42: 80-92 Crossref PubMed Scopus (23) Google Scholar resting state functional magnetic resonance imaging alterations, 7 Contreras J.A. Goñi J. Risacher S.L. et al. Cognitive complaints in older adults at risk for Alzheimer's disease are associated with altered resting-state networks. Alzheimers Dement (Amst). 2016; 6: 40-49 PubMed Google Scholar regional changes in glucose metabolism, 8 Jeong H.S. Park J.S. Song I.U. et al. Changes in cognitive function and brain glucose metabolism in elderly women with subjective memory impairment: a 24-month prospective pilot study. Acta Neurol Scand. 2017; 135: 108-114 Crossref PubMed Scopus (14) Google Scholar increased β-amyloid burden on positron emission tomography imaging, 9 La Joie R. Perrotin A. Egret S. et al. Qualitative and quantitative assessment of self-reported cognitive difficulties in nondemented elders: association with medical help seeking, cognitive deficits, and β-amyloid imaging. Alzheimers Dement (Amst). 2016; 5: 23-24 PubMed Scopus (46) Google Scholar and subtle neuropsychological findings such as increased difficulty with paired associate learning tasks. 10 Polcher A. Frommann J. Koppara A. et al. Face-name associative recognition deficits in subjective cognitive decline and mild cognitive impairment. J Alzheimers Dis. 2017; 56: 1185-1196 Crossref PubMed Scopus (28) Google Scholar In many individuals the capacity for accurate self-observation is eroded early in the progression of cognitive decline, so self-report of SMCs may emerge and then subside even before significant cognitive failure is apparent to others or measurable on the usual neuropsychological tests. For researchers and clinicians, the complex relationship between SMCs and objective impairment presents a significant challenge: What is their significance and how should they be addressed clinically? Subjective Memory Complaints are Associated with Incident Dementia in Cognitively Intact Older People, but Not in Those with Cognitive Impairment: A 24-Month Prospective Cohort StudyThe American Journal of Geriatric PsychiatryVol. 25Issue 6PreviewAlthough subjective memory complaints (SMCs) are considered a risk factor for incident dementia in older people, the effect might differ based on cognitive function. The aim of the present study was to investigate whether the effect of SMCs on the incidence of dementia in older people differed based on cognitive function. Full-Text PDF