Subjective memory complaints and cognitive impairment in older people

Subjective memory complaints (SMCs) are common in older people and are often thought to indicate cognitive impairment. We reviewed research on the relationship between SMCs and (a) current cognitive function, (b) risk of future cognitive decline, and (c) depression and personality. SMCs were found to be inconsistently related to current cognitive impairment but were more strongly related to risk of future cognitive decline. However, SMCs were consistently related to depression and some personality traits, e.g. neuroticism. In conclusion, the determinants of SMCs are complex. The utility of SMCs in the diagnosis of pre-dementia states (e.g. mild cognitive impairment) is uncertain and requires further evaluation.     

Subjective complaints and self-evaluation of memory test performance in Questionable dementia

BACKGROUND: The clinical significance of subjective memory complaints in elderly subjects has been an area of active research. In this study, we evaluated subjective complaints and self-evaluation of memory test performance in subjects with Questionable dementia (QD) and mild Alzheimer's disease (AD). METHODS: Ninety-two subjects (35 cognitively intact normal controls NC, 33 QD, and 24 mild AD) were assessed. Subjective memory complaints were evaluated using a memory inventory for the Chinese (MIC); objective assessment of awareness was assessed by the self-evaluation of own memory test performance. Cognitive function was assessed with the Alzheimer's Disease Assessment Scale-Cognitive subscale (ADAS-Cog), Category Verbal Fluency Test (CVFT) and Executive Interview (EXIT-25). Depressive symptoms were evaluated with the Cornell Scale for Depression in Dementia (CSDD). RESULTS: The total number of subjective memory complaints (MI-tol) were significantly different between different subject groups (Kruskal Wallis test, chi2 = 13.19, p = 0.001). Significant correlations between scores of the MI-tol and CSDD (r = 0.33, p < 0.001), CMMSE (r = -0.33, p < 0.001), CDR (r = 0.36, p < 0.001) were found. In self-evaluation of memory test performance, the NC group tended to under-estimate while the AD subjects tended to over-estimate their performance. Group differences in the discrepancies of self-evaluation of memory performance were significant for both the immediate (Kruskal Wallis test, chi2 = 9.86, p = 0.007) and delayed recall (Kruskal Wallis test, chi2 = 10.55, p < 0.001) trials. CONCLUSIONS: Subjects with QD and mild AD showed higher frequency of subjective memory complaints, reflecting that the subjects still retain some ability to appreciate own memory function. However, the trend for over-estimation of performance in AD subjects suggests that the precision of estimation may be suboptimal. Moreover, depressive symptoms may affect the presentation of memory complaints and this factor should be carefully considered in future prospective studies.     

Subjective memory complaints: objective neural markers in patients with Alzheimer's disease and major depressive disorder

Patients with probable Alzheimer's disease and depressive patients frequently present with subjective memory complaints. Objective distinction of underlying neuronal substrate malfunction and early cross-sectional differential diagnosis have been elusive thus far. We used repetitive learning and free recall of abstract geometric patterns during functional magnetic resonance imaging to assess episodic memory in older subjects (ages 56-64 years) who sought first-time medical attention with subjective memory complaints and were diagnosed with probable Alzheimer's disease (NINCDS-ADRDA criteria; ages 51-67 years) or major depressive disorder (DSM-IV; ages 50-65 years). Contrasting healthy seniors or depressive patients with Alzheimer's disease patients revealed superiority of hippocampal activation. Contrasting Alzheimer's disease patients with seniors showed bilateral prefrontal activity as a correlate of futile compensation of episodic memory failure. Contrasting patients who had major depressive disorder with seniors or patients who had Alzheimer's disease showed bilateral activation of the orbitofrontal cortex and the anterior cingulate. Subjective memory complaints may be classified objectively and very early with functional magnetic resonance imaging of episodic memory in groups of patients with Alzheimer's disease and depressive syndrome. This may facilitate drug trials with evaluation of specific treatments, but further studies will be needed to establish the differential diagnosis for the individual patient.     

Subjective memory complaints in Chinese subjects with mild cognitive impairment and early Alzheimer's disease

BACKGROUND: Mild cognitive impairment (MCI) represents a transitional state between normal aging and dementia. However, there is inconsistent opinion as to the validity of subjective memory complaints as a criterion for diagnosis. OBJECTIVE: This study aimed to examine the potential significance of applying a short memory questionnaire in the assessment of Chinese subjects with MCI and early dementia. METHODS: Three hundred and six ambulatory Chinese subjects were recruited. Each participant completed a short memory questionnaire. They were also assessed with the Chinese versions of the mini-mental state examination (CMMSE), Alzheimer's disease assessment scale-cognitive subscale (ADAS-Cog), category verbal fluency test (CVFT) and span tests. Severity of cognitive impairment was evaluated using the Clinical Dementia Rating (CDR); subjects with CDR 0.5 were further classified into MCI not demented (MCIND) and MCI possible incipient dementia (MCIID) depending on the subscale scores of CDR. RESULTS: An increasing frequency of memory complaints with increasing CDR was observed (Kruskal Wallis test, chi square = 21.29, df 3, p < 0.001). With a cutoff of 3 or more memory complaints, the memory questionnaire demonstrated a sensitivity of 65.3% and 70.4% in identifying subjects with incipient and early dementia respectively. Significant associations between memory complaints and most cognitive test performance were found (Spearman's correlations, p < 0.01). Logistic regression analysis revealed that educational level, the memory questionnaire, ADAS-Cog total and delayed recall scores were significant predictors of MCIID status. CONCLUSIONS: The findings suggested that a short memory questionnaire is useful in the screening of MCI, particularly in subjects who already present with subtle functioning disturbances. Subjective memory complaints were significant correlated with objective performance of memory functions, reflecting the usefulness of memory complaints in the assessment of MCI.     

Memory complaints with and without memory impairment: the impact of leukoaraiosis on cognition

White matter alterations, leukoaraiosis (LA) on structural MRI, are associated with cognitive deficits and increased risk of dementia. LA may also impact on subjective memory complaints in otherwise healthy older adults. Little is known about the interplay between LA memory complaints and cognition. We investigated cognitive phenotypes associated with LA in 42 non-demented older adults categorized as having subjective cognitive complaints with no objective cognitive impairment-the subjective cognitive impairment group (SCI; n = 12), amnesic mild cognitive impairment (aMCI; n = 20), or healthy controls (HC; n = 11). We measured LA severity on MRI with a 40-point visual rating scale. Controlling for age and Mini-Mental State Examination (MMSE) score, analyses revealed multiple between-group differences. Follow-up linear regression models investigating the underlying contributors to each clinic group's cognitive profile indicated that LA contributed to learning slope variance (after accounting for age and MMSE) but only for the SCI group. Although the SCI group showed a significantly steeper learning slope when compared to HC and aMCI, increasing LA severity negatively impacted this group's rate of learning. This, in conjunction with the significant contribution of age on SCI learning slope performance variance suggests that greater LA burden at a younger age may contribute to subtle changes in learning for individuals with subjective cognitive complaints.     

The nature of cognitive complaints in healthy older adults with and without objective memory decline

Cognitive and memory complaints were assessed in 100 healthy older adults on two occasions over 2.5 years as part of a 6-year study assessing cognition, mood, and general health factors. Diminished memory for names and actions and lapses in concentration were common complaints, regardless of the individuals' actual cognitive status. No change in cognitive complaints occurred over time, even for individuals whose memory had declined over 6 years. Cognitive complaints correlated with anxiety, depression, and general mental health but not with objectively measured memory or cognition, education or age. Complaints did not differ with gender, apolipoprotein E epsilon4 genotype, cardiovascular risk factors, or intake of sedating medications. Thus, cognitive complaints could not differentiate memory-declining older adults from cognitively normal older adults and were more closely associated with mood and general mental health than actual cognitive status, age, or potential risk factors for Alzheimer's disease. Thus, the evaluation of cognitive complaints must be broad and must consider the correspondence of complaints not only to relevant measurable cognitive abilities but also to the affect of the individual.     

The value of informant versus individual's complaints of memory impairment in early dementia

Self-reported versus informant-reported memory problems in nondemented elderly adults and in individuals with very mild and mild dementia of the Alzheimer type (DAT) were correlated with cognitive outcomes. No significant correlations were found between self-reported memory complaints and cognitive performance or (in controls) later development of dementia. In contrast, informant-reported memory loss distinguished nondemented from demented individuals and predicted future diagnosis of DAT.     

Subjective memory complaints,education, and risk of Alzheimer’s disease

BackgroundSubjective memory complaints are common in the elderly. Although memory complaints are associated with an increased risk of Alzheimer’s disease in persons with cognitive impairment as well as in persons with normal cognition, they are commonly considered of less importance than objective cognitive measures. We hypothesized that the clinical relevance of subjective memory complaints might vary with educational background.MethodsThe study was performed within the Rotterdam Study, a prospective population-based cohort study among 7983 persons 55 years and older. Subjective memory complaints and level of education were assessed in the baseline interview (1990 to 1993). During a mean follow-up of 9.0 years we identified 568 incident Alzheimer’s disease patients. We estimated the association between subjective memory complaints and risk of dementia by means of Cox proportional hazard models.ResultsThe association between subjective memory complaints and risk of Alzheimer’s disease varied across levels of education. The risk of Alzheimer’s disease associated with subjective memory complaints was higher in highly educated persons (age- and sex-adjusted hazard ratio, 2.33; 95% confidence interval [CI], 1.00–5.49) than in persons with a low education (age- and sex-adjusted hazard ratio, 1.53; 95% CI, 1.15–2.05) (P value for interaction, .02). In highly educated persons without objective cognitive impairment (Mini-Mental State Examination score, 29 or 30) the risk of Alzheimer’s disease was highest (age- and sex-adjusted hazard ratio, 2.98; 95% CI, 1.76–5.02).ConclusionsEspecially in persons with a high level of education who still perform well on formal cognitive tests, subjective memory complaints might be an important first sign of imminent Alzheimer’s disease.     

缺血性脑卒中后非痴呆认知功能障碍的危险因素

目的 探讨缺血性脑卒中后非痴呆认知功能障碍(cognitive impairment no dementia,CIND)的危险因素.方法 以19～80岁汉族初发缺血性脑卒中患者为研究对象,起病后3个月采用简易智能量表和美国精神疾病统计和诊断于册第4版修订本进行认知测定,利用单因素和多元Logistic回归分析研究CIND患者的危险因素.结果 185例研究对象纳入统计分析,42例诊断为CIND,占22.7%.多因素Logistic回归分析发现,大面积和中等面积梗死(OR:4.687,P＜0.05;OR:4.734,P＜0.05)、糖尿病(OR:2.887,P＜0.05)是缺血性卒中后CIND的独立危险因素.结论 糖尿病、梗死面积是缺血性脑卒中后CIND的独立危险因素.     

Subjective cognitive complaints versus objective neuropsychological performance in older adults with epilepsy

Memory complaints are common among older adults with epilepsy (OAE), though discrepancy between subjective complaints and objective performance often exists. This study examined how accurately OAE and their informants reported on the participant's cognitive difficulties by comparing ratings of everyday cognition to objective performance. Thirty-seven OAE and 27 older adult controls completed a brief battery of neuropsychological tests, the Beck Depression Inventory, and the Cognitive Difficulties Scale (CDS). Each participant had an informant who completed the CDS. Older adults with epilepsy performed worse than controls on cognitive testing and reported more subjective cognitive complaints. Neither participant- nor informant-reported cognitive complaints were related to performance on any of the neuropsychological tests for either the group with epilepsy or control group, but both were related to greater depressive symptoms. Results suggest that subjective report of cognitive problems by both OAE and their informants may not reliably reflect the extent to which these problems exist.     

Subjective memory complaints,mood and MCI: a follow-up study

Objectives: Subjective memory complaints (SMC) are common in older people and previous research has shown an association with mood problems, such as depression and anxiety. SMC form part of the criteria for many definitions of mild cognitive impairment (MCI), but there is controversy over whether they should be included as they may be related more strongly to mood than to objective cognitive impairment. This study aims to clarify the relationship between mood and SMC in people with MCI.

Method: This paper reports an analysis of data from the Medical Research Council Cognitive Function and Ageing study. Structured interviews were conducted with community-dwelling older people to assess a range of aspects of cognitive functioning and mood. Data from two time points approximately 24 months apart were used in this analysis. At baseline, participants without dementia or severe cognitive impairment were categorised into three groups according to cognitive status. Mood was investigated by assessing symptoms of anxiety and depression which were defined using a diagnostic algorithm. Associations were tested using logistic regression and chi square analyses.

Results: A clear association was shown between SMC and mood, both cross-sectionally and over time. The relationship between our two competing definitions of MCI suggested that mood problems were more strongly related to the presence of SMC than objective cognitive impairment.

Conclusion: SMC may be a function of anxiety and depression rather than being related to objective cognitive function. This questions whether SMC should be included in definitions of MCI.