Incidence of dementia in patients with subjective memory complaints

Examining the role of participant and study partner report in widely-used classification approaches of mild cognitive impairment in demographically-diverse community dwelling individuals: results from the Einstein aging study

Objective

The role of subjective cognitive concerns (SCC) as a diagnostic criterion for MCI remains uncertain and limits the development of a universally (or widely)-accepted MCI definition. The optimal MCI definition should define an at-risk state and accurately predict the development of incident dementia. Questions remain about operationalization of definitions of self- and informant-reported SCCs and their individual and joint associations with incident dementia.

Methods

The present study included Einstein Aging Study participants who were non-Hispanic White or Black, free of dementia at enrollment, had follow-up, and completed neuropsychological tests and self-reported SCC at enrollment to determine MCI status. Informant-reported SCC at baseline were assessed via the CERAD clinical history questionnaire. Self-reported SCC were measured using the CERAD, items from the EAS Health Self-Assessment, and the single memory item from the Geriatric Depression Scale. Cox proportional hazards models examined the association of different operationalizations of SCC with Petersen and Jak/Bondi MCI definitions on the risk of dementia, further controlling for age, sex, education, and race/ethnicity. Time-dependent sensitivity and specificity at specific time points for each definition, and Youden's index were calculated as an accuracy measure. Cox proportional hazards models were also used to evaluate the associations of combinations of self- and informant-reported SCC with the risk of incident dementia.

Results

91% of the sample endorsed at least one SCC. Youden's index showed that not including SCC in either Jak/Bondi or Petersen classifications had the best balance between sensitivity and specificity across follow-up. A subset of individuals with informants, on average, had a lower proportion of non-Hispanic Blacks and 94% endorsed at least one self-reported SCC. Both informant-reported and self-reported SCC were significantly associated with incident dementia.

Conclusion

Our findings suggest that the SCC criterion may not improve the predictive validity for dementia when included in widely-employed definitions of MCI. Consistent with some prior research, informant-reported SCC was more related to risk of incident dementia than self-reported SCC. Given that requiring informant report as a diagnostic criterion may unintentionally exclude health disparate groups, additional consideration is needed to determine how best to utilize informant-report in MCI diagnosis.

Eye-tracking paradigms for the assessment of mild cognitive impairment: a systematic review

Mild cognitive impairment (MCI), representing the 'transitional zone' between normal cognition and dementia, has become a novel topic in clinical research. Although early detection is crucial, it remains logistically challenging at the same time. While traditional pen-and-paper tests require in-depth training to ensure standardized administration and accurate interpretation of findings, significant technological advancements are leading to the development of procedures for the early detection of Alzheimer's disease (AD) and facilitating the diagnostic process. Some of the diagnostic protocols, however, show significant limitations that hamper their widespread adoption. Concerns about the social and economic implications of the increasing incidence of AD underline the need for reliable, non-invasive, cost-effective, and timely cognitive scoring methodologies. For instance, modern clinical studies report significant oculomotor impairments among patients with MCI, who perform poorly in visual paired-comparison tasks by ascribing less attentional resources to novel stimuli. To accelerate the Global Action Plan on the Public Health Response to Dementia 2017-2025, this work provides an overview of research on saccadic and exploratory eye-movement deficits among older adults with MCI. The review protocol was drafted based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Electronic databases were systematically searched to identify peer-reviewed articles published between 2017 and 2022 that examined visual processing in older adults with MCI and reported gaze parameters as potential biomarkers. Moreover, following the contemporary trend for remote healthcare technologies, we reviewed studies that implemented non-commercial eye-tracking instrumentation in order to detect information processing impairments among the MCI population. Based on the gathered literature, eye-tracking-based paradigms may ameliorate the screening limitations of traditional cognitive assessments and contribute to early AD detection. However, in order to translate the findings pertaining to abnormal gaze behavior into clinical applications, it is imperative to conduct longitudinal investigations in both laboratory-based and ecologically valid settings.

Subjective Memory Complaints Predict Decline in Memory, Instrumental Activities of Daily Living, and Social Participation in Older Adults: A Fixed-Effects Model

IMPORTANCE

Although subjective memory complaints (SMCs) have been suggested to be associated with future memory impairment, limitations in instrumental activities of daily living (IADLs), and social participation restriction, these associations are still inconclusive.

OBJECTIVE

To determine whether changes in SMCs over time predict decline in memory, IADLs, and social participation in older adults.

DESIGN

Longitudinal study.

SETTING

Community.

PARTICIPANTS

Sample 1 included 2,493 community-dwelling older adults drawn from the Health and Retirement Study (HRS) data collected between 2004 and 2018. Sample 2 included 1,644 community-dwelling older adults drawn from the HRS data collected between 2008 and 2018.

OUTCOMES AND MEASURES

Self-reported SMCs, memory function, self-reported IADL performance, and self-reported social participation.

RESULTS

The mean age of Sample 1 at baseline was 70.16 yr; 1,468 (58.88%) were female. In Sample 1, immediate and delayed memory (all ps < .001) and IADL performance (p < .01) declined over time. Increases in SMCs over time significantly predicted future immediate and delayed memory declines (p < .01 and p < .001, respectively) and future IADL performance decline (p < .001), after controlling for depressive symptoms. The mean age of Sample 2 at baseline was 71.52 yr; 928 (56.45%) were female. In Sample 2, social participation declined over time (all ps < .001). Increases in SMCs over time significantly predicted future social participation decline (p < .05), after controlling for depressive symptoms.

CONCLUSIONS AND RELEVANCE

Increases in SMCs predict future decline in memory, IADL performance, and social participation after accounting for depressive symptoms. What This Article Adds: SMCs can be used as an early indicator of future memory impairment, IADL limitations, and social participation restrictions in older adults. Furthermore, interventions that minimize SMCs may help older adults achieve successful aging.

Evaluating measurement properties of subjective cognitive decline self-reported outcome measures: a systematic review

BACKGROUND

Subjective cognitive decline (SCD) is present in the early stage of preclinical Alzheimer's disease (AD) and is associated with an increased risk of further cognitive decline and AD dementia later in life. Early detection of at-risk groups with subjective complaints is critical for targeted dementia prevention at the earliest. Accurate assessment of SCD is crucial. However, current measures lack important psychometric evaluations and or reporting.

OBJECTIVES

To systematically evaluate measurement properties of self-reported outcome measures (PROMs) used to assess SCD in the older adult population with or at risk of AD.

METHODS AND ANALYSIS

We used the Preferred Reporting Items for Systematic Reviews and Meta-Analysis Protocols 2015 Checklist for reporting. We conducted a literature search, screened, and included validation studies of SCD based on self-reported questionnaires from both population-based and clinical studies, conducted in older adults (≥ 55). We critically appraised the included primary studies using the Consensus-based Standards for the selection of health Measurement Instruments (COSMIN) guidelines.

RESULTS

Sixteen studies met the inclusion criteria. The included studies reported psychometric properties of 17 SCD self-reported questionnaires. We extracted data on the structural validity, internal consistency, test-retest reliability, and cross-cultural validity and found a widespread proneness to bias across studies, and a marked heterogeneity is assessed and reported measurement properties that prevented the consolidation of results.

CONCLUSION

Our findings suggest that available SCD questionnaires lack content validity evaluation. Currently available measurements of SCD lack development and validation standards. Further work is needed to develop and validate SCD self-reported measurement with good quality measurement properties.

Power Spectral Changes of Quantitative EEG in the Subjective Cognitive Decline: Comparison of Community Normal Control Groups

PURPOSE

The purpose of this study is to compare and analyze the power spectral changes between subjective cognitive decline (SCD) subjects and normal controls (NC) while checking the preclinical stage of AD in the SCD subjects and to use the derived data for biomarker research that can diagnose early-stage AD in the future.

METHODS

We recruited 23 SCD patients and 23 normal control subjects and QEEG analysis including power spectral density (PSD) and source-level analysis were performed. An automated preprocessing procedure and statistical analysis were performed by iSync Brain^® (iMediSync Inc., Republic of Korea) (https://isyncbrain.com/) using the international standard 10-20 system (19 electrodes).

RESULTS

Absolute PSD, there was no statistically significant difference in all of the EEG power measurements of the 19 channels. In the relative PSD analysis, the average delta band power of the SCD group was significantly higher in Fp2, F4, and F8 than NC. Alpha1 band power of the O1 channel was 22.56±16.05 for the SCD group and 33.19±19.05 for the NC (p-value <0.05). Source-level analysis did not show a statistically significant difference.

CONCLUSION

SCD subjects showed a partial increase of delta waves in the frontal lobe region and a partial decrease in alpha1, a fast wave in the occipital region, compared to the NC. SCD is considered one of the earliest clinical symptoms of AD and it is predicted to be related to minor nerve damage. We were able to observe the power spectral changes in SCD subjects in this cross-sectional study, a large number of subjects and longitudinal studies are needed to evaluate their predictability for future deterioration such as conversion to MCI.

The tip-of-the-tongue phenomenon in older adults with subjective memory complaints

In older adults with subjective memory complaints (SMCs), featuring a decline in memory but not exhibiting problems during medical examinations and objective memory tests, the weak links between nodes evident in the word retrieval process can be a primary factor for predicting mild cognitive impairment and dementia. This study examined the frequency of the “Tip-of-the-Tongue” (ToT) phenomenon according to age and subjective memory complaints of older adults, and identified differences in the resolution method using sequential cues. A celebrity naming task was performed on older adults (aged 50 to 79) with SMCs (n = 30) and without SMCs (n = 30), comparing the frequency of the ToT phenomenon and in resolution methods. We found that, even if our subjects with SMCs obtained normal results in the objective neuropsychology test, they experienced a significantly higher frequency of the ToT phenomenon than those without SMCs. In addition, subjects with SMCs showed a significantly lower rate of resolution, both spontaneous and following a syllabic cue, compared to those without SMCs. SMCs can be a very early marker of degenerative diseases causing cognitive dysfunction, and thus the selection of appropriate tools for early detection of SMCs is important. The proper naming task may sensitively detect subclinical symptoms of SMCs in subjects who are not classified as patients with cognitive impairments on general neuropsychological test. In addition, this task can identify weak connections between semantic and phonological nodes due to changes in the neural region of older adults with SMCs.

Executive and Language Subjective Cognitive Decline Complaints Discriminate Preclinical Alzheimer's Disease from Normal Aging

BACKGROUND

There is a need to specify the profile of subjective cognitive decline in preclinical Alzheimer's disease (preAD).

OBJECTIVES

To explore specific items of the Subjective Cognitive Decline Questionnaire (SCD-Q) that discriminate preAD from normal aging.

METHODS

68 cognitively normal older adults were classified as controls (n = 52) or preAD (n = 16) according to amyloid-β (Aβ) levels. An exploratory factor analysis and item analysis of the SCD-Q were performed. Informant reports of the SCD-Q were used to corroborate the findings of self-reports. One-year neuropsychological follow-up was available.

RESULTS

Four SCD-Q factors were extracted: EM-factor (episodic memory), A-factor (attention), O-factor (organization), and L-factor (language). PreAD reported a significantly higher decline in L-factor (F(1) = 6.49; p = 0.014) and A-factor (F(1) = 4.04; p = 0.049) compared to controls, and showed a higher frequency of perceived decline in SCD-Q items related with language and executive tasks (Sig-items.) Significant discriminative powers for Aβ-positivity were found for L-factor (AUC = 0.75; p = 0.003) and A-factor (AUC = 0.74; p = 0.004). Informants in the preAD group confirmed significantly higher scores in L-factor and Sig-items. A significant time×group interaction was found in the Semantic Fluency and Stroop tests, with the preAD group showing a decrease in performance at one-year.

CONCLUSIONS

Our results suggest that SCD-Q items related with language and executive decline may help in prediction algorithms to detect preAD. Validation in an independent population is needed.

Subjective Cognitive Impairment Cohort (SCIENCe): study design and first results

BACKGROUND

We aimed to describe the Subjective Cognitive Impairment Cohort (SCIENCe) study design, to cross-sectionally describe participant characteristics, and to evaluate the SCD-plus criteria.

METHODS

The SCIENCe is a prospective cohort study of subjective cognitive decline (SCD) patients. Participants undergo extensive assessment, including cerebrospinal fluid collection and optional amyloid positron emission tomography scan, with annual follow-up. The primary outcome measure is clinical progression.

RESULTS

Cross-sectional evaluation of the first 151 participants (age 64 ± 8, 44% female, Mini-Mental State Examination 29 ± 2) showed that 28 (25%) had preclinical Alzheimer's disease (AD) (amyloid status available n = 114 (75%)), 58 (38%) had subthreshold psychiatry, and 65 (43%) had neither. More severe subjective complaints were associated with worse objective performance. The SCD-plus criteria age ≥ 60 (OR 7.7 (95% CI 1.7-38.9)) and apolipoprotein E (genotype) e4 (OR 4.8 (95% CI 1.6-15.0)) were associated with preclinical AD.

CONCLUSIONS

The SCIENCe study confirms that SCD is a heterogeneous group, with preclinical AD and subthreshold psychiatric features. We found a number of SCD-plus criteria to be associated with preclinical AD. Further inclusion and follow-up will address important questions related to SCD.

The relationship among depression, subjective cognitive impairment, and neuropsychological performance in multiple sclerosis

The aim of this study was to examine, within the context of a treatment study, the relative contributions of depression and neuropsychological performance on patient ratings of cognitive functioning in a cohort of 58 moderately-depressed multiple sclerosis (MS) patients. All participants were randomized to one of three 16-week conventional treatments for depression. Assessments were conducted pre and post-treatment using: (1) Cognitive Function subscale of the Multiple Sclerosis Quality of Life-54 (MSQOL-54) to evaluate subjective cognitive impairment (SC), (2) Beck Depression Inventory (BDI), and (3) a neuropsychological index score (NP). Prior to treatment, 8% of the variance in SC was explained by NP, whereas 14% of the variance was explained by BDI, above and beyond NP. At post-treatment, patients were classified as ‘responders’ (BDI<11) and ‘nonresponders’ (BDI≥11). Among those participants classified as ‘responders’, NP accounted for 39% of the variance in SC, and BDI did not significantly predict SC. The results of this study suggest that depression may influence subjective reports of cognitive impairment, but these reports may not be reliably related to objective neuropsychological performance. Furthermore, patients may be more accurate reporters of their cognitive impairment after successful treatment for depression, suggesting that depression decreases the accuracy of patient reported cognitive impairment.

Incident Subjective Cognitive Decline Does Not Predict Mortality in the Elderly--Results from the Longitudinal German Study on Ageing, Cognition, and Dementia (AgeCoDe)

OBJECTIVE

Subjective cognitive decline (SCD) might represent the first symptomatic representation of Alzheimer's disease (AD), which is associated with increased mortality. Only few studies, however, have analyzed the association of SCD and mortality, and if so, based on prevalent cases. Thus, we investigated incident SCD in memory and mortality.

METHODS

Data were derived from the German AgeCoDe study, a prospective longitudinal study on the epidemiology of mild cognitive impairment (MCI) and dementia in primary care patients over 75 years covering an observation period of 7.5 years. We used univariate and multivariate Cox regression analyses to examine the relationship of SCD and mortality. Further, we estimated survival times by the Kaplan Meier method and case-fatality rates with regard to SCD.

RESULTS

Among 971 individuals without objective cognitive impairment, 233 (24.0%) incidentally expressed SCD at follow-up I. Incident SCD was not significantly associated with increased mortality in the univariate (HR = 1.0, 95% confidence interval = 0.8-1.3, p = .90) as well as in the multivariate analysis (HR = 0.9, 95% confidence interval = 0.7-1.2, p = .40). The same applied for SCD in relation to concerns. Mean survival time with SCD was 8.0 years (SD = 0.1) after onset.

CONCLUSION

Incident SCD in memory in individuals with unimpaired cognitive performance does not predict mortality. The main reason might be that SCD does not ultimately lead into future cognitive decline in any case. However, as prevalence studies suggest, subjectively perceived decline in non-memory cognitive domains might be associated with increased mortality. Future studies may address mortality in such other cognitive domains of SCD in incident cases.

Incident subjective memory complaints and the risk of subsequent dementia

OBJECTIVE

In this study, we aimed to analyze the association between new-incident-subjective memory complaints (SMC) and risk of subsequent dementia in a general population sample aged 75+ years.

METHOD

Data were derived from follow-up (FUP) waves I-V of the population-based Leipzig Longitudinal Study of the Aged (LEILA75+). We used the Kaplan-Meier survival method to estimate dementia-free survival times of individuals with and without incident SMC and multivariable Cox proportional hazards regression to assess the association between incident SMC and risk of subsequent dementia, controlled for covariates.

RESULTS

Of 443 non-demented individuals, 58 (13.1%) developed dementia during a subsequent 5.4-year follow-up period. Participants with incident SMC showed a significantly higher progression to dementia (18.5% vs. 10.0%; P=0.010) and a significantly shorter mean dementia-free survival time than those without (6.2 vs. 6.8 years; P=0.008). The association between incident SMC and risk of subsequent dementia remained significant in the multivariable Cox analysis (adjusted hazard ratio=1.8; P=0.028).

CONCLUSION

Our findings suggest higher progression to dementia and shorter dementia-free survival in older individuals with incident SMC. These findings support the notion that such subjective complaints should be taken seriously in clinical practice as possible early indicators of incipient dementia.

A conceptual framework for research on subjective cognitive decline in preclinical Alzheimer's disease

There is increasing evidence that subjective cognitive decline (SCD) in individuals with unimpaired performance on cognitive tests may represent the first symptomatic manifestation of Alzheimer's disease (AD). The research on SCD in early AD, however, is limited by the absence of common standards. The working group of the Subjective Cognitive Decline Initiative (SCD-I) addressed this deficiency by reaching consensus on terminology and on a conceptual framework for research on SCD in AD. In this publication, research criteria for SCD in pre-mild cognitive impairment (MCI) are presented. In addition, a list of core features proposed for reporting in SCD studies is provided, which will enable comparability of research across different settings. Finally, a set of features is presented, which in accordance with current knowledge, increases the likelihood of the presence of preclinical AD in individuals with SCD. This list is referred to as SCD plus.

The sensitivity and specificity of subjective memory complaints and the subjective memory rating scale, deterioration cognitive observee, mini-mental state examination, six-item screener and clock drawing test in dementia screening

BACKGROUND

The effectiveness of dementia screening depends on the availability of suitable screening tools with good sensitivity and specificity to confidently distinguish normal age-related cognitive decline from dementia. The aim of this study was to evaluate the discriminant validity of 7 screening measures for dementia.

METHODS

A sample of 140 participants aged ≥60 years living in a residential facility for the aged were assessed clinically and assigned caseness for dementia using the Diagnostic and Statistical Manual of Mental Disorders, 4th edition, text revised diagnostic criteria. Sensitivity and specificity of a selection of the following screening measures were tested using receiver operating characteristic (ROC) analysis for individual and combined tests: the Mini-Mental State Examination (MMSE), Six-Item Screener (SIS), Subjective Memory Complaint, Subjective Memory Complaint Clinical (SMCC), Subjective Memory Rating Scale (SMRS), Deterioration Cognitive Observee (DECO) and the Clock Drawing Test (CDT).

RESULTS

Using ROC analyses, the SMCC, MMSE and CDT were found to be 'moderately accurate' in screening for dementia with an area under the curve (AUC) >0.70. The AUCs for the SIS (0.526), SMRS (0.661) and DECO (0.687) classified these measures as being 'less accurate'. At recommended cutoff scores, the SMCC had a sensitivity of 90.9% and specificity of 45.7%; the MMSE had a sensitivity of 63.6% and a specificity of 76.0%, and the CDT had a sensitivity of 44.4% and a specificity of 88.9%. Combining the SMCC and MMSE did not improve their predictive power except for a modest increase when using the sequential rule.

CONCLUSION

The SMCC is composed of valid screening questions that have high sensitivity, are simple to administer and ideal for administration at the community or primary health care level as a first level of 'rule-out' screening. The MMSE can be included at a second stage of screening at the general hospital level and the CDT in specialist clinical settings. Sequential use of the SMCC and MMSE will improve the specificity of the former and the sensitivity of the latter.

Psychosocial factors involved in memory and cognitive failures in people with myalgic encephalomyelitis/chronic fatigue syndrome

BACKGROUND

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is characterized by persistent emotional, mental, and physical fatigue accompanied by a range of neurological, autonomic, neuroendocrine, immune, and sleep problems. Research has shown that psychosocial factors such as anxiety and depression as well as the symptoms of the illness, have a significant impact on the quality of life of people with ME/CFS. In addition, individuals may suffer from deficits in memory and concentration. This study set out to explore the relationships between variables which have been found to contribute to cognitive performance, as measured by prospective and retrospective memory, and cognitive failures.

METHODS

Eighty-seven people with ME/CFS answered questionnaires measuring fatigue, depression, anxiety, social support, and general self-efficacy. These were used in a correlational design (multiple regression) to predict cognitive function (self-ratings on prospective and retrospective memory), and cognitive failures.

RESULTS

Our study found that fatigue, depression, and general self-efficacy were directly associated with cognitive failures and retrospective (but not prospective) memory.

CONCLUSION

Although it was not possible in this study to determine the cause of the deficits, the literature in this area leads us to suggest that although the pathophysiological mechanisms of ME/CFS are unclear, abnormalities in the immune system, including proinflammatory cytokines, can lead to significant impairments in cognition. We suggest that fatigue and depression may be a result of the neurobiological effects of ME/CFS and in addition, that the neurobiological effects of the illness may give rise to both fatigue and cognitive deficits independently.

Subjective memory complaints in elders: depression, anxiety, or cognitive decline?

OBJECTIVES

To study the association of subjective memory complaints (SMC) with affective state and cognitive performance in elders.

MATERIALS AND METHODS

We studied community dwelling elderly persons with normal physical examination. Participants completed questionnaires regarding memory difficulties and lifestyle habits, the Geriatric Depression Scale (GDS) and the Spielberger State-Trait Anxiety Inventory (STAI). Depending on their answers to the question about their memory condition, participants were divided into complainers and non-complainers and to five groups according to their MMSE scores. These data have been compared to objective cognitive performance according to Mindstreams - a computerized neuropsychological battery. A logistic regression was performed to evaluate odds ratios (OR) and 95% confidence intervals (CI) for those factors, which were associated with SMС (dependent variable).

RESULTS

Of 636 consecutive subjects (61% females), 507 participants (79.7%) had SMС. Presence of SMC was inversely correlated with MMSE scores, (r = -0.108; P for trend = 0.007). GDS and STAI scores were higher among subjects with SMC (OR = 1.23: CI 95%: 1.1-1.36 and OR = 1.03: CI 95%: 1.01-1.07, respectively). SMC did not correlate with objective cognitive performance measured by Mindstreams.

CONCLUSIONS

Subjective memory complaints are associated with sub-syndromal depression and anxiety in healthy cognitively normal elders.

Characterizing spontaneously reported cognitive complaints: the development and reliability of a classification instrument

BACKGROUND

The characteristics and associated risks of spontaneously reported cognitive complaints have not been investigated due to the lack of a classification instrument.

METHODS

In phase 1, a classification system with descriptive categories and cognitive domains was developed by experts through a modified Delphi technique. In phase 2, 180 elderly patients seeking medical attention for cognitive complaints provided free reports of their cognitive difficulties and each complaint was recorded verbatim. Three observers were asked to classify each complaint into a descriptive category. Perceived cognitive function was further characterized using the Memory Complaint Questionnaire (MAC-Q).

RESULTS

The patients reported 493 spontaneous complaints, with a range of 1-6 complaints per patient and a mean of 2.7 (±1.3). The proportion of complaints that could be classified into a category by each of the three observers varied from 91.9% to 95.7%. Inter-observer agreement assessed using the κ statistic varied from 0.79 to 1 for descriptive categories and 0.83 to 0.97 for domains. Compared with the MAC-Q, spontaneously reported complaints provided complementary information by avoiding the cueing effect provoked by the questionnaire. The total number of complaints and their occurrences in specific domains were associated with important sociodemographic and clinical factors, indicating that their meaning and associated risks need to be further investigated.

CONCLUSION

The instrument developed in this study proved to be a practical tool for classifying the majority of spontaneously reported cognitive complaints with high reliability. Further studies are needed to investigate clinical usefulness of this approach.

Early dysfunction of functional connectivity in healthy elderly with subjective memory complaints

It is still an open question whether subjective memory complaints (SMC) can actually be considered to be clinically relevant predictors for the development of an objective memory impairment and even dementia. There is growing evidence that suggests that SMC are associated with an increased risk of dementia and with the presence of biological correlates of early Alzheimer's disease. In this paper, in order to shed some light on this issue, we try to discern whether subjects with SMC showed a different profile of functional connectivity compared with subjects with mild cognitive impairment (MCI) and healthy elderly subjects. In the present study, we compare the degree of synchronization of brain signals recorded with magnetoencephalography between three groups of subjects (56 in total): 19 with MCI, 12 with SMC and 25 healthy controls during a memory task. Synchronization likelihood, an index based on the theory of nonlinear dynamical systems, was used to measure functional connectivity. Briefly, results show that subjects with SMC have a very similar pattern of connectivity to control group, but on average, they present a lower synchronization value. These results could indicate that SMC are representing an initial stage with a hypo-synchronization (in comparison with the control group) where the brain system is still not compensating for the failing memory networks, but behaving as controls when compared with the MCI subjects.

Memory control beliefs and everyday forgetfulness in adulthood: the effects of selection, optimization, and compensation strategies

Controlling for age, gender, education, and self-rated health, the present study used regression analyses to examine the relationships between memory control beliefs and self-reported forgetfulness in the context of the meta-theory of Selective Optimization with Compensation (SOC). Findings from this online survey (N = 409) indicate that, among adult New Zealanders, a higher sense of memory control accounts for a 22.7% reduction in self-reported forgetfulness. Similarly, optimization was found to account for a 5% reduction in forgetfulness while the strategies of selection and compensation were not related to self-reports of forgetfulness. Optimization partially mediated the beneficial effects that some memory beliefs (e.g., believing that memory decline is inevitable and believing in the potential for memory improvement) have on forgetfulness. It was concluded that memory control beliefs are important predictors of self-reported forgetfulness while the support for the SOC model in the context of memory controllability and everyday forgetfulness is limited.

Which symptoms can distinguish between subjective cognitive impairment (SCI) and mild cognitive impairment (MCI)?

The SCI, the MCI, and the Alzheimer's disease (AD) are on a spectrum of disease progression; therefore, identification of the earliest signs of cognitive deterioration is becoming a crucial issue. The goal of this study was to examine symptom characteristics and distinguish predictive symptoms in patients with MCI compared with SCI, using caregiver questionnaires. We assessed the Korean Dementia Screening Questionnaire (KDSQ) and Seoul Instrumental activities of Daily Living (S-IADL) of 344 subjects with SCI and 697 with MCI. Multivariate logistic regression analyses were conducted after adjusting for age, sex, and educational status. Common and rare symptoms were similar between the SCI and MCI groups. The most distinguishing features of KDSQ were 'Finds it hard to go somewhere on his/her own using public transportation' (odds ratio=OR=4.56, p<0.0001), 'Has difficulty in operating appliances' (OR=2.47, p=0.001), and 'Keeps repeating the same question' (OR=2.03, p<0.0001). In S-IADL, the most outstanding features were 'using household appliances' (OR=3.99, p<0.0001), 'taking medication' (OR=2.38, p=0.01), and 'using public transportation' (OR=1.94, p=0.04). The dysfunction in 'using household appliance' and 'using public transportation' reflect the possibility of MCI rather than SCI. Therefore, it is suggested that these symptoms also have a discriminative and predictive power in identifying SCI.

Development of the Cognitive Dysfunction Questionnaire (CDQ) in a population based sample

The study reports on the development of a questionnaire for assessment of adult cognitive dysfunction (CDQ). Participants in a population-based sample (65±15 years, N=370) responded to a 90-item pilot version covering multiple aspects of memory/cognition. Based on exploratory principal components analyses and correlations with criterion measures of cognitive functioning (MMSE, Block Design, semantic/episodic memory), 20 items loading on 6 components were selected for the final version of the questionnaire. Cronbach's α for the total score was 0.90. There was evidence of construct validity as judged by correlations between CDQ scores, objective cognitive measures, and a subjective memory measure (PRMQ). Discriminant validity was demonstrated by a low and non-significant correlation with depressive symptoms. Further evidence of construct validity was provided by correlations with age and educational attainment. In conclusion, the CDQ is promising as a self-rating screening tool for cognitive dysfunction, and will be the subject of further development and validation.

Subjective memory complaints in the elderly may be related to factors other than cognitive deficit

Prevalence of subjective memory complaints (SMC) in elderly community dwellers (ECD) ranges from 25 to 50%. Some controversy exists over the association between SMC and cognitive status.

Subjective memory decline in healthy community-dwelling elders. What does this complain mean?

OBJECTIVES

Subjective feelings of memory decline are fairly common among the elderly. The causes of this are heterogeneous, and may be related to both affective and cognitive disorders. We attempted to explore the associations between subjective and cognitive measures.

MATERIALS AND METHODS

Healthy subjects were studied. They completed questionnaires regarding memory difficulties and lifestyle habits, the Geriatric Depression scale (GDS), and the Spielberger State-Trait Anxiety Inventory. Cognitive functions were tested using the Mini-Mental State Exam and supplemented with NeuroTrax, a computerized neurophysiological battery. Univariate logistic regression model was applied to estimate odd ratios (OR) and 95% confidence intervals of associations.

RESULTS

Of 341 consecutive non-depressed subjects, 257 participants (75.4%) reported subjective memory decline (SMD). Subjects with and without SMD did not differ in age, gender, education, marital status, employment and life-style. Subjects with SMD had elevated GDS scores (OR = 1.14, 95% CI: 1.003-1.29), white anxiety level showed a tendency to be increased (OR = 1.03, 95% CI: 0.99-1.06). Comparison of cognitive performance has not revealed differences in cognitive domains between subjects with and without SMD.

CONCLUSIONS

SMD in healthy elderly people is associated with sub-clinical depression even among those without objectively measured cognitive decline.

Do subjective memory complaints predict senile Alzheimer dementia?

Many elderly complain about their memory and undergo dementia screening by the Mini-Mental State Examination (MMSE). While objective memory impairment always precedes Alzheimer dementia (AD) it is unclear whether subjective memory complaints are predicting AD. We tried to answer this question in a prospective cohort study. The 75-years old non-demented inhabitants of Vienna-Transdanube were investigated for conversion to AD after 30 months. The predictive value of subjective memory complaints was analysed in two groups: subjects with high MMSE-score (28-30) and subjects with low MMSE-score (23-27). Only in subjects with high MMSE univariate analyses showed an association between subjective memory complaints and incident AD. In both groups the verbal memory test was the main predictor of AD in multivariate analyses. We suggest to perform memory testing in subjects complaining about memory irrespective of their performance in a screening procedure like the MMSE.

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.

Decline in verbal memory in non-demented older adults

Decline in memory function was detected in 30% of healthy community-dwelling elderly over 6 years using a task assessing delayed word list recall. Individuals with memory decline over time also demonstrated relative deficits on additional tasks of memory and learning, a task of working memory and executive function, and on a verbal (category) fluency task at their most recent assessment. These relative deficits in the performance of individuals with memory decline cannot be explained by age-related changes, education, intelligence, mood, health-related factors, or the individuals' APOE epsilon 4 status. Decline in memory performance did not result in greater complaints of cognitive difficulties when compared with normal elderly, nor did it limit overall participation in life activities. Although the significance of memory decline in the current study was not determined quantitatively, memory decline is consistent with the early deterioration characteristic of mild cognitive impairment and preclinical Alzheimer's disease and confirms the need to monitor individuals with objective memory decline, even when these individuals fall within normal limits for a given neuropsychological task.

Subjective cognitive complaints, neuropsychological performance, affective and behavioural symptoms in non-demented patients

OBJECTIVE

Subjective cognitive complaints (SCC) have been previously investigated to establish whether they are risk factors for dementia, but no clear-cut conclusions have emerged. In this study non-demented patients with SCC were studied and the neuropsychological findings, affective and behavioural aspects and parameters with the highest correct classifications in discriminating patients who had only SCC but no objective clinical and neuropsychological impairment, i.e. no cognitive impairment (NCI) patients and those with objective neuropsychological deficits, namely patients with mild cognitive (MCI) were analyzed.

METHODS

Consecutive non-demented outpatients with SCC were enrolled of over 9 months and examined using neuropsychological tests and scales for depression, anxiety and behaviour. Clinical criteria and neuropsychological test results were used to classify patients into groups of NCI, MCI and subtypes of MCI.

RESULTS

Ninety-two patients with SCC were included; 49 of them had objective deficits (MCI patients), whereas 43 were without any clinical and cognitive impairment (NCI patients). These patients had lower age, higher education and better general cognitive indices than MCI patients who had higher caregiver distress, depression and irritability. The combination of a battery for mental deterioration and for behavioural memory assessment were the most discriminative in differentiating the two groups.

CONCLUSIONS

An objective cognitive impairment, reaching the criteria for a MCI diagnosis, was present in almost half of patients having SCC. MCI patients have more behavioural disturbances than NCI subjects. SCC should not be underestimated and appropriate neuropsychological assessment is required to reassure subjects with normal results and to identify patients with MCI.

Cognitive complaints compared to performance on a mental state screening test in elderly outpatients

Memory and other cognitive complaints are common in the elderly population. However, the clinical meaning of these complaints remains controversial.

OBJECTIVES

The goal of this study was to investigate the association between cognitive complaints and performance on a mental state screening test in elderly patients attended for the first time at the Neurogeriatric and Dementia (NGA) Outpatient Clinic within a major University hospital.

METHODS

Two hundred patients referred to the NGA Clinic during 2005, 2006 and 2007 first semesters participated in the study. The variables of interest were:(a) source of and reason for referral;(b) whether or not they had previously been evaluated with the screening test (Mini Mental State Exam - MMSE) by their physicians before referral to our specialized clinic;(c) cognitive complaints; and(d) performance on the screening test (MMSE) at the NGA Clinic.

RESULTS

The main reason for referral to the NGA clinic was cognitive complaints 63% (N=126), where only 5% (N=10) of the referred patients had been previously evaluated by the cognitive screening test (MMSE or equivalent). Of the 135 patients who presented cognitive complaints during the first appointment, 52 (38%) presented MMSE scores below the education-adjusted cut-off. No association between cognitive complaint and performance on the MMSE during the first evaluation at the NGA Clinic was observed (χ2=3.04, p=0.1).

CONCLUSIONS

Although cognitive complaints among elders should not be disregarded, the mental state screening evaluation is crucial for the detection of clinically significant cognitive impairment.

Mild cognitive impairment in general practice: age-specific prevalence and correlate results from the German study on ageing, cognition and dementia in primary care patients (AgeCoDe)

BACKGROUND

Although mild cognitive impairment (MCI) represents a high-risk factor for developing dementia, little is known about the prevalence of MCI among patients of general practitioners (GPs).

AIMS

Estimation of age-specific prevalence for original and modified concepts of MCI and their association with sociodemographic, medical and genetic (apoE epsilon4 genotype) factors among patients of GPs.

METHODS

A GP practice sample of 3,327 individuals aged 75+ was assessed by structured clinical interviews.

RESULTS

Prevalence was 15.4% (95% CI = 14.1-16.6) for original and 25.2% (95% CI = 23.7-26.7) for modified MCI. Rates increased significantly with older age. Positive associations were found for apoE epsilon4 allele, vascular diseases and depressive symptoms.

CONCLUSION

MCI is frequent in elderly patients of GPs. GPs have a key position in secondary prevention and care of incipient cognitive deterioration up to the diagnosis of dementia.

EEG MARKERS FOR COGNITIVE DECLINE IN ELDERLY SUBJECTS WITH SUBJECTIVE MEMORY COMPLAINTS

New treatments for Alzheimer's disease require early detection of cognitive decline. Most studies seeking to identify markers of early cognitive decline have focused on a limited number of measures. We sought to establish the profile of brain function measures which best define early neuropsychological decline. We compared subjects with subjective memory complaints to normative controls on a wide range of EEG derived measures, including a new measure of event-related spatio-temporal waves and biophysical modeling, which derives anatomical and physiological parameters based on subject's EEG measurements. Measures that distinguished the groups were then related to cognitive performance on a variety of learning and executive function tasks. The EEG measures include standard power measures, peak alpha frequency, EEG desynchronization to eyes-opening, and global phase synchrony. The most prominent differences in subjective memory complaint subjects were elevated alpha power and an increased number of spatio-temporal wave events. Higher alpha power and changes in wave activity related most strongly to a decline in verbal memory performance in subjects with subjective memory complaints, and also declines in maze performance and working memory reaction time. Interestingly, higher alpha power and wave activity were correlated with improved performance in reverse digit span in the subjective memory complaint group. The modeling results suggest that differences in the subjective memory complaint subjects were due to a decrease in cortical and thalamic inhibitory gains and slowed dendritic time-constants. The complementary profile that emerges from the variety of measures and analyses points to a nonlinear progression in electrophysiological changes from early neuropsychological decline to late-stage dementia, and electrophysiological changes in subjective memory complaint that vary in their relationships to a range of memory-related tasks.