Subjective memory complaints in community dwelling healthy older people: the influence of brain and psychopathology

Clusters of cognitive performance predict long-term cognitive impairment in elderly patients with subjective memory complaints and healthy controls

INTRODUCTION

Patients with subjective memory complaints (SMC) may include subgroups with different neuropsychological profiles and risks of cognitive impairment.

METHODS

Cluster analysis was performed on two datasets (n: 630 and 734) comprising demographic and neuropsychological data from SMC and healthy controls (HC). Survival analyses were conducted on clusters. Bayesian model averaging assessed the predictive utility of clusters and other biomarkers.

RESULTS

Two clusters with higher and lower than average cognitive performance were detected in SMC and HC. Assignment to the lower performance cluster increased the risk of cognitive impairment in both datasets (hazard ratios: 1.78 and 2.96; Plog-rank: 0.04 and <0.001) and was associated with lower hippocampal volumes and higher tau/amyloid beta 42 ratios in cerebrospinal fluid. The effect of SMC was small and confounded by mood.

DISCUSSION

This study provides evidence of the presence of cognitive clusters that hold biological significance and predictive value for cognitive decline in SMC and HC.

HIGHLIGHTS

Patients with subjective memory complaints include two cognitive clusters. Assignment to the lower performance cluster increases risk of cognitive impairment. This cluster shows a pattern of biomarkers consistent with incipient Alzheimer's disease pathology. The same cognitive cluster structure is found in healthy controls. The effect of memory complaints on risk of cognitive decline is small and confounded.

White matter hyperintensity load varies depending on subjective cognitive decline criteria

Increased age and cognitive impairment is associated with an increase in cerebrovascular pathology often measured as white matter hyperintensities (WMHs) on MRI. Whether WMH burden differs between cognitively unimpaired older adults with subjective cognitive decline (SCD +) and without subjective cognitive decline (SCD -) remains conflicting, and could be related to the methods used to identify SCD. Our goal was to examine if four common SCD classification methods are associated with different WMH accumulation patterns between SCD + and SCD - . A total of 535 cognitively unimpaired older adults with 1353 time points from the Alzheimer's Disease Neuroimaging Initiative were included in this study. SCD was operationalized using four different methods: Cognitive Change Index (CCI), Everyday Cognition Scale (ECog), ECog + Worry, and Worry. Linear mixed-effects models were used to investigate the associations between SCD and overall and regional WMH burden. Overall temporal WMH burden differences were only observed with the Worry questionnaire. Higher WMH burden change over time was observed in SCD + compared to SCD - in the temporal and parietal regions using the CCI (temporal, p = .01; parietal p = .02) and ECog (temporal, p = .02; parietal p = .01). For both the ECog + Worry and Worry questionnaire, change in WMH burden over time was increased in SCD + compared to SCD - for overall, frontal, temporal, and parietal WMH burden (p < .05). These results show that WMH burden differs between SCD + and SCD - depending on the questionnaire and the approach (regional/global) used to measure WMHs. The various methods used to define SCD may reflect different types of underlying pathologies.

Sex Differences in Cerebral Small Vessel Disease: A Systematic Review and Meta-Analysis

Background: Cerebral small vessel disease (SVD) is a common cause of stroke, mild cognitive impairment, dementia and physical impairments. Differences in SVD incidence or severity between males and females are unknown. We assessed sex differences in SVD by assessing the male-to-female ratio (M:F) of recruited participants and incidence of SVD, risk factor presence, distribution, and severity of SVD features. Methods: We assessed four recent systematic reviews on SVD and performed a supplementary search of MEDLINE to identify studies reporting M:F ratio in covert, stroke, or cognitive SVD presentations (registered protocol: CRD42020193995). We meta-analyzed differences in sex ratios across time, countries, SVD severity and presentations, age and risk factors for SVD. Results: Amongst 123 relevant studies (n = 36,910 participants) including 53 community-based, 67 hospital-based and three mixed studies published between 1989 and 2020, more males were recruited in hospital-based than in community-based studies [M:F = 1.16 (0.70) vs. M:F = 0.79 (0.35), respectively; p < 0.001]. More males had moderate to severe SVD [M:F = 1.08 (0.81) vs. M:F = 0.82 (0.47) in healthy to mild SVD; p < 0.001], and stroke presentations where M:F was 1.67 (0.53). M:F did not differ for recent (2015-2020) vs. pre-2015 publications, by geographical region, or age. There were insufficient sex-stratified data to explore M:F and risk factors for SVD. Conclusions: Our results highlight differences in male-to-female ratios in SVD severity and amongst those presenting with stroke that have important clinical and translational implications. Future SVD research should report participant demographics, risk factors and outcomes separately for males and females. Systematic Review Registration: [PROSPERO], identifier [CRD42020193995].

Neuropsychiatric symptoms associated with cerebral small vessel disease: a systematic review and meta-analysis

BACKGROUND

Cerebral small vessel disease, a common cause of vascular dementia, is often considered clinically silent before dementia or stroke become apparent. However, some individuals have subtle symptoms associated with acute MRI lesions. We aimed to determine whether neuropsychiatric and cognitive symptoms vary according to small vessel disease burden.

METHODS

In this systematic review and meta-analysis, we searched MEDLINE, EMBASE, and PsycINFO for articles published in any language from database inception to Jan 24, 2020. We searched for studies assessing anxiety, apathy, delirium, emotional lability, fatigue, personality change, psychosis, dementia-related behavioural symptoms or cognitive symptoms (including subjective memory complaints), and radiological features of cerebral small vessel disease. We extracted reported odds ratios (OR), standardised mean differences (SMD), and correlations, stratified outcomes by disease severity or symptom presence or absence, and pooled data using random-effects meta-analyses, reporting adjusted findings when possible. We assessed the bias on included studies using the Risk of Bias for Non-randomized Studies tool. This study is registered with PROSPERO, CRD42018096673.

FINDINGS

Of 7119 papers identified, 81 studies including 79 cohorts in total were eligible for inclusion (n=21 730 participants, mean age 69·2 years). Of these 81 studies, 45 (8120 participants) reported effect estimates. We found associations between worse white matter hyperintensity (WMH) severity and apathy (OR 1·41, 95% CI 1·05-1·89) and the adjusted SMD in apathy score between WMH severities was 0·38 (95% CI 0·15-0·61). Worse WMH severity was also associated with delirium (adjusted OR 2·9, 95% CI 1·12-7·55) and fatigue (unadjusted OR 1·63, 95% CI 1·20-2·22). WMHs were not consistently associated with subjective memory complaints (OR 1·34, 95% CI 0·61-2·94) and unadjusted SMD for WMH severity between these groups was 0·08 (95% CI -0·31 to 0·47). Anxiety, dementia-related behaviours, emotional lability, and psychosis were too varied or sparse for meta-analysis; these factors were reviewed narratively. Overall heterogeneity varied from 0% to 79%. Only five studies had a low risk of bias across all domains.

INTERPRETATION

Apathy, fatigue, and delirium associated independently with worse WMH, whereas subjective cognitive complaints did not. The association of anxiety, dementia-related behaviours, emotional lability, and psychosis with cerebral small vessel disease require further investigation. These symptoms should be assessed longitudinally to improve early clinical detection of small vessel disease and enable prevention trials to happen early in the disease course, long before cognition declines.

FUNDING

Chief Scientist Office of the Scottish Government, UK Dementia Research Institute, Fondation Leducq, Stroke Association Garfield-Weston Foundation, Alzheimer's Society, and National Health Service Research Scotland.

Subjective Cognitive Complaints Given in Questionnaire: Relationship With Brain Structure, Cognitive Performance and Self-Reported Depressive Symptoms in a 25-Year Retrospective Cohort Study

BACKGROUND

Subjective cognitive complaints are common but it is unclear whether they indicate an underlying pathological process or reflect affective symptoms.

METHOD

800 community-dwelling older adults were drawn from the Whitehall II cohort. Subjective cognitive complaint inquiry for memory and concentration, a range of neuropsychological tests and multimodal MRI were performed in 2012-2016. Subjective complaints were again elicited after 1 year. Group differences in grey and white matter, between those with and without subjective complaints, were assessed using voxel-based morphometry and tract-based spatial statistics, respectively. Mixed effects models assessed whether cognitive decline or depressive symptoms (over a 25-year period) were associated with later subjective complaints. Analyses were controlled for potential confounders and multiple comparisons.

RESULTS

Mean age of the sample at scanning was 69.8 years (±5.1, range: 60.3-84.6). Subjective memory complaints were common (41%) and predicted further similar complaints later (mean 1.4 ± 1.4 years). There were no group differences in grey matter density or white matter integrity. Subjective complaints were not cross-sectionally or longitudinally associated with objectively assessed cognition. However, those with subjective complaints reported higher depressive symptoms ("poor concentration": odds ratio = 1.12, 95% CI 1.07-1.18; "poor memory": odds ratio = 1.18, 1.12-1.24).

CONCLUSIONS

In our sample subjective complaints were consistent over time and reflected depressive symptoms but not markers of neurodegenerative brain damage or concurrent or future objective cognitive impairment. Clinicians assessing patients presenting with memory complaints should be vigilant for affective disorders. These results question the rationale for including subjective complaints in a spectrum with Mild Cognitive Impairment diagnostic criteria.

Effects of a lifestyle development program designed to reduce the risk factors for cognitive decline on the mental health of elderly individuals

BACKGROUND

The incidence of Alzheimer's disease (AD) along with depression is high in the elderly. In the present study, a program that allows the elderly individuals to voluntarily manage and develop lifestyles that may reduce the risk factors for cognitive decline was applied to the participants to evaluate its effect on the mental health of these individuals.

METHODS

The participants were randomly assigned to an intervention group and a control group. The program was conducted during 7 months in the intervention group, and it had seven times of group activities, performed once a month for about 1 h, and individual activities to reduce the risk factors for cognitive decline, performed every day. To evaluate the effects of the program on the mental health of the participants, the Geriatric Depression Scale (GDS) and Philadelphia Geriatric Center Morale Scale (PGC) were used. These two scales were applied twice to the intervention and control groups.

RESULTS

The GDS score revealed no change in the score in the intervention group before and after the 7-month program implementation; however, in the control group, the score was significantly higher after program implementation than that before. The PGC score revealed no change in the intervention group before and after 7-month program implementation; however, in the control group, the score was significantly lower after program implementation than that before. Additionally, it revealed no change in the GDS score in the depression-prone control group before and after 7-month program implementation; however, in the depression-prone intervention group, the GDS score was significantly lower after program implementation than that before.

CONCLUSIONS

The intervention program that allows the elderly individuals to voluntarily manage and develop lifestyles that may reduce the risk factors for cognitive decline is expected to maintain mental health in elderly individuals.

Memory complaints inventory profiles: Differentiating neurocognitive impairment, depression, and non-credible performance

The Memory Complaints Inventory (MCI) is a symptom validity measure designed to assess exaggerated memory complaints. The aim of current study was to develop memory complaint profiles on the MCI to distinguish between various neurocognitive disorders, depression, and non-credible performance. This study utilized MCI scores (N = 244) from a neuropsychology clinic to determine the presence of, and difference between, subjective memory complaints between a depression group, non-credible group, and subgroups of cognitive impairment (Alzheimer's Dementia, Vascular Dementia, and Mild Cognitive Impairment). Significant differences were found on MCI endorsement between cognitive impairment, depression, and non-credible groups. This pattern indicated fewer memory complaints for cognitive impairment groups when compared to depression and non-credible groups; the non-credible group had the highest MCI scores overall. ROC analyses revealed recommended clinical cutoff values with high specificity for distinguishing between the non-credible group and other groups. The findings provided further evidence for the MCI as a symptom validity measure, given its ability to differentiate between a non-credible group and clinical groups. Replication of the study's findings would result in reliable genuine subjective memory complaint profiles to provide additional diagnostic and prognostic specificity in neuropsychological practice.

Motoric cognitive risk syndrome: Integration of two early harbingers of dementia in older adults

Dementia is characterized by a long preclinical phase that may last years to decades before the onset of mild cognitive impairment. Slow gait speed and subjective memory complaint commonly co-occur during this preclinical phase, and each is a strong independent predictor of cognitive decline and dementia. Motoric cognitive risk (MCR) syndrome is a pre-dementia syndrome that combines these two early harbingers of dementia. The risk of cognitive decline or dementia is stronger for MCR than for either slow gait speed or subjective memory complaint alone. Slow gait speed and subjective memory complaint have several common risk factors: cardiovascular disease, diabetes mellitus, abnormal cortisol profiles, low vitamin D levels, brain atrophy with decreased hippocampal volume, and increased deposition of beta-amyloid in the brain. The underlying pathogenesis of MCR remains poorly understood. Metabolomics and proteomics have great potential to provide new insights into biological pathways involved in MCR during the long preclinical phase preceding dementia.

Functional cognitive disorders: a systematic review

Cognitive symptoms are common, and yet many who seek help for cognitive symptoms neither have, nor go on to develop, dementia. A proportion of these people are likely to have functional cognitive disorders, a subtype of functional neurological disorders, in which cognitive symptoms are present, associated with distress or disability, but caused by functional alterations rather than degenerative brain disease or another structural lesion. In this Review, we have systematically examined the prevalence and clinical associations of functional cognitive disorders, and related phenotypes, within the wider cognitive disorder literature. Around a quarter of patients presenting to memory clinics received diagnoses that might indicate the presence of functional cognitive disorders, which were associated with affective symptoms, negative self-evaluation, negative illness perceptions, non-progressive symptom trajectories, and linguistic and behavioural differences during clinical interactions. Those with functional cognitive disorder phenotypes are at risk of iatrogenic harm because of misdiagnosis or inaccurate prediction of future decline. Further research is imperative to improve diagnosis and identify effective treatments for functional cognitive disorders, and better understanding these phenotypes will also improve the specificity of diagnoses of prodromal degenerative brain disease.

Neurological Changes and Depression: 2020 Update

This article covers current research on the relationship between depression and cognitive impairment in older adults. First, it approaches the clinical assessment of late-life depression and comorbid cognitive impairment. Cognitive risk factors for suicide are discussed. Research is then provided on neuropsychological changes associated with depression, discussing subjective cognitive impairment, mild cognitive impairment, and dementia profiles. In addition, literature regarding neuroimaging and biomarker findings in depressed older adults is presented. Finally, therapeutic models for treatment of late-life depression are discussed, including psychotherapy models, holistic treatments, pharmacologic approaches, and brain stimulation therapies.

Subjective Cognitive Decline and APOE ɛ4: A Systematic Review

Individuals with subjective cognitive decline (SCD) report self-perceived declines in cognitive function but perform within normal limits on standardized tests. However, for some, these self-perceived changes may herald eventual decline to Alzheimer's disease (AD). In light of this, the relationship between SCD and APOE ɛ4, a known genetic risk factor for AD, has garnered interest; however, no systematic review of this literature exists. The current review (n = 36 articles) examined the prevalence of APOE ɛ4 in SCD samples relative to healthy and objectively impaired samples, and summarized APOE ɛ4-related risk of conversion from SCD to AD. Univariate ANOVA indicated that APOE ɛ4 frequency was comparable between healthy control and SCD samples, yet significantly higher in objectively impaired samples (i.e., MCI, AD) relative to either of these groups. Narrative review provided mixed evidence linking coincident APOE ɛ4-positive genotype and SCD to structural neuropathology. Though there was little evidence to suggest that APOE ɛ4 predisposes individuals to developing SCD, both APOE ɛ4 and SCD were found to confer individual and multiplicative risk of conversion to objective cognitive impairment. Combined, it is likely that a relationship between APOE ɛ4, SCD, and AD exists, though its exact nature remains undetermined. A clearer understanding of these relationships is hindered by a lack of standardization in SCD classification and a dearth of longitudinal outcome research. Wide-scale adoption of genetic screening for dementia risk in persons with SCD is considered premature at this time. Ethical considerations and clinical implications of genetic testing for dementia risk are discussed.

Subjective cognitive decline, brain imaging biomarkers, and cognitive functioning in patients with a history of vascular disease: the SMART-Medea study

We estimated associations of subjective cognitive decline (SCD) with neuroimaging markers of dementia and cognitive functioning in patients with a history of vascular disease without objective cognitive impairment. Within the Second Manifestations of ARTerial disease-Memory, depression and aging study, 599 patients (62 ± 9 years) had 1.5 T brain magnetic resonance imaging and cognitive testing at the baseline and after 8 years of follow-up. Using multiple regression analyses, we estimated cross-sectional and longitudinal associations of SCD according to research criteria with volumes of total brain, hippocampus, white matter hyperintensities, and presence of lacunes and with memory, executive functioning, information processing speed, and working memory. SCD was associated with increased risk of lacunes at the baseline (relative risk = 1.48, 95% confidence interval: 1.03; 2.12) but not during follow-up. No significant associations with volumes of white matter hyperintensities, total brain, or hippocampus were observed. SCD was cross-sectionally associated with poorer executive functioning and speed but not during follow-up. More prospective studies are needed to further elucidate the relationship between SCD, brain imaging markers, and cognitive decline and the role of SCD in the preclinical stage of Alzheimer's disease.

Reduced Cerebral Blood Flow in Mild Cognitive Impairment Assessed Using Phase-Contrast MRI

There is increasing evidence of a vascular contribution to Alzheimer's disease (AD). In some cases, prior work suggests that chronic brain hypoperfusion could play a prime pathogenic role contributing to the accumulation of amyloid-β,while other studies favor the hypothesis that vascular dysfunction and amyloid pathology are independent, although synergistic, mechanisms contributing to cognitive impairment. Vascular dysfunction can be evaluated by assessing cerebral blood flow impairment. Phase contrast velocity mapping by MRI offers a non-invasive means of quantifying the total inflow of blood to the brain. This quantitative parameter could be a sensitive indicator of vascular disease at early stages of AD. In this work, phase contrast MRI was used to evaluate cerebral hemodynamics in patients with subjective memory complaints, amnestic mild cognitive impairment, and mild to moderate AD, and compare them with control subjects. Results showed that blood flow and velocity were decreased in the patients with cognitive dysfunction and the decrease correlated with the degree of cognitive impairment as assessed by means of neuropsychological tests. Total cerebral blood flow measurements were clearly reduced in AD patients, but more importantly appeared to be sensitive enough to distinguish between healthy subjects and those with mild cognitive impairment. A quantitative measurement of total brain blood flow could potentially predict vascular dysfunction and compromised brain perfusion in early stages of AD.

Diminution of context association memory structure in subjects with subjective cognitive decline

Alzheimer's disease (AD) progresses insidiously from the preclinical stage to dementia. While people with subjective cognitive decline (SCD) have normal cognitive performance, some may be in the preclinical stage of AD. Neurofibrillary tangles appear first in the transentorhinal cortex, followed by the entorhinal cortex in the clinically silent stage of AD. We expected the earliest changes in subjects with SCD to occur in medial temporal subfields other than the hippocampal proper. These selective structural changes would affect specific memory subcomponents. We used the Family Picture subtest of the Wechsler Memory Scale-III, which was modified to separately compute character, activity, and location subscores for episodic memory subcomponents. We recruited 43 subjects with SCD, 44 subjects with amnesic mild cognitive impairment, and 34 normal controls. MRI was used to assess cortical thickness, subcortical gray matter volume, and fractional anisotropy. The results demonstrated that SCD subjects showed significant cortical atrophy in their bilateral parahippocampus and perirhinal and the left entorhinal cortices but not in their hippocampal regions. SCD subjects also exhibited significantly decreased mean fractional anisotropy in their bilateral uncinate fasciculi. The diminution of cortical thickness over the mesial temporal subfields corresponded to brain areas with early tangle deposition, and early degradation of the uncinate fasciculus was in accordance with the retrogenesis hypothesis. The parahippocampus and perirhinal cortex contribute mainly to context association memory while the entorhinal cortex, along with the uncinate fasciculus, contributes to content-related contextual memory. We proposed that context association and related memory structures are vulnerable in the SCD stage.

Neurologic Changes and Depression

This article covers current research on the relationship between depression and cognitive impairment in older adults. First, it approaches the clinical assessment of late-life depression and comorbid cognitive impairment. Cognitive risk factors for suicide are discussed. Research is then provided on neuropsychological changes associated with depression, discussing subjective cognitive impairment, mild cognitive impairment, and dementia profiles. Additionally, literature regarding neuroimaging and biomarker findings in depressed older adults is presented. Finally, therapeutic models for treatment of late-life depression are also discussed, including psychotherapy models, holistic treatments, pharmacologic approaches, and brain-stimulation therapies.

Identity processes as a predictor of memory beliefs in older adults

OBJECTIVES

The impact of identity processes (identity assimilation, identity accommodation, and identity balance) on memory beliefs was explored.

METHOD

Individually administered questionnaires (e.g. depressive symptoms, subjective health, identity processes, memory beliefs) and a brief neuropsychological assessment of cognitive abilities were completed during a one-time interview with 82 participants aged 58-92 years-old (M = 74.68, SD = 10.95). Forty (49.4%) identified their race as White/Caucasian, 38 (46.9%) identified their race as Black/African American, and 3 (3.7%) indicated no primary racial/ethnic group.

RESULTS

Hierarchical regression analyses revealed that identity processes account for differences in memory beliefs beyond established predictors. Specifically, identity accommodation and identity balance predicted memory self-efficacy beyond depression and subjective health. These findings are congruent with identity process theory; however, the impact of identity assimilation in this population was unremarkable. Exploratory analyses also indicated that the identity processes have a stronger relationship to some domains of memory self-efficacy (i.e. anxiety, capacity) than others (i.e. perceived change, locus of control).

CONCLUSION

Beliefs about memory and their integration into an adaptable, yet consistent self-concept are an important element of identity for aging individuals. Additional research is needed to determine the unique role of identity accommodation and identity balance in understanding cognitive functioning and ultimately the impact on potential clinical applications, such as related health-seeking behavior among older adults. Tailored interventions could be developed to facilitate optimal utilization of health care services at a time when early diagnosis of memory-related disorders is critical for future planning and care decisions.

The association between subjective memory complaint and objective cognitive function in older people with previous major depression

The goal of this study is to investigate associations between subjective memory complaint and objective cognitive performance in older people with previous major depression–a high-risk sample for cognitive impairment and later dementia. A cross-sectional study was carried out in people aged 60 or over with previous major depression but not fulfilling current major depression criteria according to DSM-IV-TR. People with dementia or Mini-Mental State Examination score less than 17 were excluded. Subjective memory complaint was defined on the basis of a score ≧4 on the subscale of Geriatric Mental State schedule, a maximum score of 8. Older people aged equal or over 60 without any psychiatric diagnosis were enrolled as healthy controls. Cognitive function was evaluated using a series of cognitive tests assessing verbal memory, attention/speed, visuospatial function, verbal fluency, and cognitive flexibility in all participants. One hundred and thirteen older people with previous major depression and forty-six healthy controls were enrolled. Subjective memory complaint was present in more than half of the participants with depression history (55.8%). Among those with major depression history, subjective memory complaint was associated with lower total immediate recall and delayed verbal recall scores after adjustment. The associations between subjective memory complaint and worse memory performance were stronger in participants with lower depressive symptoms (Hamilton Depression Rating Scale score<7). The results suggest subjective memory complaint may be a valid appraisal of memory performance in older people with previous major depression and consideration should be given to more proactive assessment and follow-up in these clinical samples.

Magnetic Resonance Volumetry: Prediction of Subjective Memory Complaints and Mild Cognitive Impairment, and Associations with Genetic and Cardiovascular Risk Factors

Background/Aims

Subjective memory complaints (SMC) are strong predictors of mild cognitive impairment (MCI) and subsequent Alzheimer's disease. Our aims were to see if fully automated cerebral MR volume measurements could distinguish subjects with SMC and MCI from controls, and if probable parental late-onset Alzheimer's disease (LOAD), apolipoprotein E ε4 genotype, total plasma homocysteine, and cardiovascular risk factors were associated with MR volumetric findings.

Methods

198 stroke-free subjects comprised the control (n = 58), the SMC (n = 25) and the MCI (n = 115) groups. Analysis of covariance and receiver operating characteristic curve was used to see if MR volumetry distinguished subjects with SMC and MCI from controls.

Results

Subjects with SMC and MCI had significantly larger lateral ventricles and smaller hippocampal volumes than controls. The area under the curve in subjects with SMC and MCI compared to that of controls was less than 0.68 for all volumes of intracranial structures. There was an interaction between sex and probable parental LOAD for hippocampal volume, with a significant association between probable parental LOAD and hippocampal volume in women.

Conclusions

Fully automated MR volumetry can distinguish subjects with SMC and MCI from controls in a general population, but insufficiently to assume a clear clinical role. Research on sporadic LOAD might benefit from a sex-specific search for genetic risk factors.

Altered Brain Connectivity in Early Postmenopausal Women with Subjective Cognitive Impairment

Cognitive changes after menopause are a common complaint, especially as the loss of estradiol at menopause has been hypothesized to contribute to the higher rates of dementia in women. To explore the neural processes related to subjective cognitive complaints, this study examined resting state functional connectivity in 31 postmenopausal women (aged 50–60) in relationship to cognitive complaints following menopause. A cognitive complaint index was calculated using responses to a 120-item questionnaire. Seed regions were identified for resting state brain networks important for higher-order cognitive processes and for areas that have shown differences in volume and functional activity associated with cognitive complaints in prior studies. Results indicated a positive correlation between the executive control network and cognitive complaint score, weaker negative functional connectivity within the frontal cortex, and stronger positive connectivity within the right middle temporal gyrus in postmenopausal women who report more cognitive complaints. While longitudinal studies are needed to confirm this hypothesis, these data are consistent with previous findings suggesting that high levels of cognitive complaints may reflect changes in brain connectivity and may be a potential marker for the risk of late-life cognitive dysfunction in postmenopausal women with otherwise normal cognitive performance.

Vascular contributions to cognitive impairment, clinical Alzheimer's disease, and dementia in older persons

There is growing evidence suggesting that vascular pathologies and dysfunction play a critical role in cognitive impairment, clinical Alzheimer's disease, and dementia. Vascular pathologies such as macroinfarcts, microinfarcts, microbleeds, small and large vessel cerebrovascular disease, and white matter disease are common especially in the brains of older persons where they contribute to cognitive impairment and lower the dementia threshold. Vascular dysfunction resulting in decreased cerebral blood flow, and abnormalities in the blood brain barrier may also contribute to the Alzheimer's disease (AD) pathophysiologic process and AD dementia. This review provides a clinical-pathological perspective on the role of vessel disease, vascular brain injury, alterations of the neurovascular unit, and mixed pathologies in the Alzheimer's disease pathophysiologic process and Alzheimer's dementia. This article is part of a Special Issue entitled: Vascular Contributions to Cognitive Impairment and Dementia edited by M. Paul Murphy, Roderick A. Corriveau and Donna M. Wilcock.

Relational memory and self-efficacy measures reveal distinct profiles of subjective memory concerns in older adults

OBJECTIVE

Subjective memory concerns (SMCs) in healthy older adults are associated with future decline and can indicate preclinical dementia. However, SMCs may be multiply determined, and often correlate with affective or psychosocial variables rather than with performance on memory tests. Our objective was to identify sensitive and selective methods to disentangle the underlying causes of SMCs.

METHOD

Because preclinical dementia pathology targets the hippocampus, we hypothesized that performance on hippocampally dependent relational memory tests would correlate with SMCs. We thus administered a series of memory tasks with varying dependence on relational memory processing to 91 older adults, along with questionnaires assessing depression, anxiety, and memory self-efficacy. We used correlational, regression, and mediation analyses to compare the variance in SMCs accounted for by these measures.

RESULTS

Performance on the task most dependent on relational memory processing showed a stronger negative association with SMCs than did other memory performance metrics. SMCs were also negatively associated with memory self-efficacy. These 2 measures, along with age and education, accounted for 40% of the variance in SMCs. Self-efficacy and relational memory were uncorrelated and independent predictors of SMCs. Moreover, self-efficacy statistically mediated the relationship between SMCs and depression and anxiety, which can be detrimental to cognitive aging.

CONCLUSIONS

These data identify multiple mechanisms that can contribute to SMCs, and suggest that SMCs can both cause and be caused by age-related cognitive decline. Relational memory measures may be effective assays of objective memory difficulties, while assessing self-efficacy could identify detrimental affective responses to cognitive aging. (PsycINFO Database Record

Education modifies the type of subjective memory complaints in older people

OBJECTIVE

The aim of the study is to analyze the relationship between the level of education and the profile of subjective memory complaints (SMC).

METHODS

Participants were healthy volunteers aged >50 years old, from a community-based sample. Educational attainment was self-reported, and participants were subsequently assembled in four groups, according to the highest grade achieved in school. Additionally, they were questioned about their own memory abilities using an SMC scale (total score 0-21) and assessed for the presence of depressive symptoms.

RESULTS

A total of 841 participants aged 50-92 years old were included. The mean total score on the SMC scale was 5.3 ± 3.2, and 80.4% of the subjects reported at least one minor complaint about their memory. There was no correlation between total SMC score and higher educational level, even after accounting for the presence of depressive symptoms. However, regarding specific SMC, the use of notes to avoid forgetting was more frequent in higher levels of education, whereas the opposite trend was observed for complaints of transient confusion.

CONCLUSION

Educational attainment possibly modulates the frequency and type of SMC in normal aging. Because these complaints are a major symptom for the diagnosis of cognitive decline, it seems relevant to consider the level of education when interpreting subjective reports on memory.

Association between subjective memory complaints and depressive symptoms after adjustment for genetic and family environmental factors in a Japanese twin study

OBJECTIVES

The aim of this study was to investigate the association between subjective memory complaints (SMCs) and depressive symptoms, with and without adjustment for genetic and family environmental factors.

METHODS

We conducted a cross-sectional study using twins and measured SMCs and depressive symptoms as outcomes and explanatory variables, respectively. First, we performed regression analyses using generalized estimating equations to investigate the associations between SMCs and depressive symptoms without adjustment for genetic and family environmental factors (individual-level analyses). We then performed regression analyses for within-pair differences using monozygotic (MZ) and dizygotic (DZ) twin pairs and MZ twin pairs to investigate these associations with adjustment for genetic and family environmental factors by subtracting the values of one twin from those of co-twin variables (within-pair level analyses). Therefore, differences between the associations at individual- and within-pair level analyses suggested confounding by genetic factors.

RESULTS

We included 556 twins aged ≥ 20 years. In the individual-level analyses, SMCs were significantly associated with depressive symptoms in both males and females [standardized coefficients: males, 0.23 (95% CI 0.08-0.38); females, 0.35 (95% CI 0.23-0.46)]. In the within-pair level analyses using MZ and same-sex DZ twin pairs, SMCs were significantly associated with depressive symptoms. In the within-pair level analyses using the MZ twin pairs, SMCs were significantly associated with depressive symptoms [standardized coefficients: males, 0.32 (95% CI 0.08-0.56); females, 0.24 (95% CI 0.13-0.42)].

CONCLUSIONS

This study suggested that SMCs were significantly associated with depressive symptoms after adjustment for genetic and family environmental factors.

Hippocampal atrophy is associated with subjective memory decline: The PATH Through Life study

OBJECTIVE

To investigate whether subjective memory decline (SMD) in cognitively healthy individuals is associated with hippocampal atrophy.

METHODS

Multiple regression analyses assessing the relationship between hippocampal atrophy over 4 years and SMD at baseline and follow-up in 305 cognitively healthy individuals aged 60-64 years free from dementia, mild cognitive impairment, and other neurological disorders.

RESULTS

SMD at baseline was not a significant predictor of hippocampal atrophy. However, SMD at follow-up was associated with greater hippocampal atrophy. Associations were reduced but remained significant after controlling for anxiety and depression symptomatology.

CONCLUSION

Hippocampal atrophy was associated with incident/persisting SMD and this association was not, or only partly, explained by anxiety and depression symptomatology. These results are consistent with a biological origin to subjective memory decline. SMD should be included in screening and neuropsychological batteries.

Biochemical and neuroimaging studies in subjective cognitive decline: progress and perspectives

Neurodegeneration due to Alzheimer's disease (AD) can progress over decades before dementia becomes apparent. Indeed, patients with mild cognitive impairment (MCI) already demonstrate significant lesion loads. In most cases, MCI is preceded by subjective cognitive decline (SCD), which is applied to individuals who have self-reported memory-related complaints and has been associated with a higher risk of future cognitive decline and conversion to dementia. Based on the schema of a well-received model of biomarker dynamics in AD pathogenesis, it has been postulated that SCD symptoms may result from compensatory changes in response to β-amyloid accumulation and neurodegeneration. Although SCD is considered a prodromal stage of MCI, it is also a common manifestation in old age, independent of AD, and the predictive value of SCD for AD pathology remains controversial. Here, we provide a review focused on the contributions of cross-sectional and longitudinal analogical studies of biomarkers and neuroimaging evidence in disentangling under what conditions SCD may be attributable to AD pathology. In conclusion, there is promising evidence indicating that clinicians should be able to differentiate pre-AD SCD based on the presence of pathophysiological biomarkers in cerebrospinal fluid (CSF) and neuroimaging. However, this neuroimaging approach is still at an immature stage without an established rubric of standards. A substantial amount of work remains in terms of replicating recent findings and validating the clinical utility of identifying SCD.

Utility of the cognitive difficulties scale and association with objective test performance

Subjective memory complaints (SMCs) are commonly noted in memory disorder clinic patients. The present study sought to examine the presence of SMCs on the Cognitive Difficulties Scale (CDS) in older adults and to examine the relationship between CDS scores and current cognitive ability. Participants were 50 adults diagnosed with possible/probable Alzheimer's disease (AD), 100 with amnestic mild cognitive impairment (MCI) and 84 cognitively healthy controls (HCs). Participants completed a neuropsychological evaluation and the self- and informant-reported CDS. Results indicated that greater self-reported SMCs were noted in the group with MCI ; however, self-reported CDS scores were associated with cognition in HCs only. Informant-reported CDS scores were predictive of cognitive ability in the diagnosis of MCI but not AD, indicating the importance of obtaining caregiver report in the evaluation of memory disorders. As AD is a neurodegenerative disorder, SMCs lose value in determining degree of cognitive impairment as disease stage increases.

Screening for cognitive and affective dysfunction in patients suspected of mild cognitive impairment

OBJECTIVE

Disturbances of affect expression and perception, as well as accuracy of predicting memory difficulties, have been reported in various brain dysfunctional groups. Screening tests of higher cerebral functions seldom sample these dimensions. The goal of this study was to determine if patients with mild cognitive impairment (MCI) of the amnestic type would demonstrate impairments in these domains, as well as show expected memory deficits.

METHODS

Thirty-nine French-speaking patients with a clinical diagnosis of MCI were compared with 39 age- and education-matched normal functioning individuals on the French translation of the Barrow Neurological Institute Screen for Higher Cerebral Functions (BNIS). Patients and controls also made subjective ratings regarding their cognitive and affective functioning in everyday life.

RESULTS

Patients with MCI performed significantly worse than controls on the BNIS subtests sampling memory, orientation, affect expression and perception, and accurate prediction of memory performance. They did not differ on other subtests of the BNIS, as predicted. Poor self-awareness (i.e., inaccurate prediction of the number of words one could recall after distraction) correlated with self-reported deficits in several areas of cognitive and affective functioning.

CONCLUSION

This sample of MCI patients demonstrated disturbances not only in memory but also in self-awareness and affect expression and perception on the BNIS. These dimensions should be included in the neuropsychological assessment of patients suspected of MCI.

Subjective memory complaints, cognitive performance, and psychological factors in healthy older adults

OBJECTIVE

To determine whether subjective memory complaints (SMCs) are associated with performance on objective cognitive measures and psychological factors in healthy, community-dwelling older adults.

METHOD

The cohort was composed of adults, 65 years and older with no clinical evidence of cognitive impairment (n = 125). Participants were administered: CogState computerized neurocognitive battery, Prospective Retrospective Memory Questionnaire, personality and meaning-in-life measures.

RESULTS

SMCs were associated with poorer performance on measures of executive function (p = 0.001). SMCs were also associated with impaired delayed recall (p = 0.006) but this did not remain significant after statistical adjustment for multiple comparisons. SMCs were inversely associated with conscientiousness (p = 0.004) and directly associated with neuroticism (p < 0.001). Higher scores on SMCs were associated with higher perceived stress (p = 0.001), and ineffective coping styles (p = 0.001). Factors contributing to meaning-in-life were associated with fewer SMCs (p < 0.05).

CONCLUSIONS

SMCs may reflect early, subtle cognitive changes and are associated with personality traits and meaning-in-life in healthy, older adults.

Profile of cognitive complaints in vascular mild cognitive impairment and mild cognitive impairment

Objective. Vascular mild cognitive impairment (VaMCI) is differentiated from mild cognitive impairment (MCI) by the presence of vascular events such as stroke or small vessel disease. Typically, MCI and VaMCI patients present with subjective complaints regarding cognition; however, little is known about the specific nature of these complaints. We aimed to create a profile of subjective cognitive complaints in MCI and VaMCI patients with similar levels of objective cognitive performance. Methods. Twenty MCI and twenty VaMCI patients were recruited from a Memory Disorders Clinic in Toronto. Subjective cognitive complaints were assessed and categorized using the Neuropsychological Impairment Scale. Results. MCI and VaMCI patients achieved similar scores on measures of objective cognitive function (P > 0.100). However, the VaMCI group had more subjective complaints than the MCI group (P = 0.050), particularly in the critical items, cognitive efficiency, memory, and verbal learning domains of the Neuropsychological Impairment Scale. Conclusions. Our findings support the idea that VaMCI and MCI differ in their clinical profiles, independent of neuroimaging. VaMCI patients have significantly more subjective cognitive complaints and may be exhibiting particular deficits in memory, verbal learning, and cognitive efficiency. Our findings promote the need for further research into VaMCI-specific cognitive deficits.

Are empirically-derived subtypes of mild cognitive impairment consistent with conventional subtypes?

Given the importance of identifying dementia prodromes for future treatment efforts, we examined two methods of diagnosing mild cognitive impairment (MCI) and determined whether empirically-derived MCI subtypes of these diagnostic methods were consistent with one another as well as with conventional MCI subtypes (i.e., amnestic, non-amnestic, single-domain, multi-domain). Participants were diagnosed with MCI using either conventional Petersen/Winblad criteria (n = 134; >1.5 SDs below normal on one test within a cognitive domain) or comprehensive neuropsychological criteria developed by Jak et al. (2009) (n = 80; >1 SD below normal on two tests within a domain), and the resulting samples were examined via hierarchical cluster and discriminant function analyses. Results showed that neuropsychological profiles varied depending on the criteria used to define MCI. Both criteria revealed an Amnestic subtype, consistent with prodromal Alzheimer's disease (AD), and a Mixed subtype that may capture individuals in advanced stages of MCI. The comprehensive criteria uniquely yielded Dysexecutive and Visuospatial subtypes, whereas the conventional criteria produced a subtype that performed within normal limits, suggesting its susceptibility to false positive diagnostic errors. Whether these empirically-derived MCI subtypes correspond to dissociable neuropathologic substrates and represent reliable prodromes of dementia will require additional follow-up.