Differences in quantitative methods for measuring subjective cognitive decline - results from a prospective memory clinic study

Structural neuroimaging changes associated with subjective cognitive decline from a clinical sample

BACKGROUND

Alzheimer's disease (AD) is characterized by progressive deterioration of cognitive functions. Some individuals with subjective cognitive decline (SCD) are in the early phase of the disease and subsequently progress through the AD continuum. Although neuroimaging biomarkers could be used for the accurate and early diagnosis of preclinical AD, the findings in SCD samples have been heterogeneous. This study established the morphological differences in brain magnetic resonance imaging (MRI) findings between individuals with SCD and those without cognitive impairment based on a clinical sample of patients defined according to SCD-Initiative recommendations. Moreover, we investigated baseline structural changes in the brains of participants who remained stable or progressed to mild cognitive impairment or dementia.

METHODS

This study included 309 participants with SCD and 43 healthy controls (HCs) with high-quality brain MRI at baseline. Among the 99 subjects in the SCD group who were followed clinically, 32 progressed (SCDp) and 67 remained stable (SCDnp). A voxel-wise statistical comparison of gray and white matter (WM) volume was performed between the HC and SCD groups and between the HC, SCDp, and SCDnp groups. XTRACT ATLAS was used to define the anatomical location of WM tract damage. Region-of-interest (ROI) analyses were performed to determine brain volumetric differences. White matter lesion (WML) burden was established in each group.

RESULTS

Voxel-based morphometry (VBM) analysis revealed that the SCD group exhibited gray matter atrophy in the middle frontal gyri, superior orbital gyri, superior frontal gyri, right rectal gyrus, whole occipital lobule, and both thalami and precunei. Meanwhile, ROI analysis revealed decreased volume in the left rectal gyrus, bilateral medial orbital gyri, middle frontal gyri, superior frontal gyri, calcarine fissure, and left thalamus. The SCDp group exhibited greater hippocampal atrophy (p < 0.001) than the SCDnp and HC groups on ROI analyses. On VBM analysis, however, the SCDp group exhibited increased hippocampal atrophy only when compared to the SCDnp group (p < 0.001). The SCD group demonstrated lower WM volume in the uncinate fasciculus, cingulum, inferior fronto-occipital fasciculus, anterior thalamic radiation, and callosum forceps than the HC group. However, no significant differences in WML number (p = 0.345) or volume (p = 0.156) were observed between the SCD and HC groups.

CONCLUSIONS

The SCD group showed brain atrophy mainly in the frontal and occipital lobes. However, only the SCDp group demonstrated atrophy in the medial temporal lobe at baseline. Structural damage in the brain regions was anatomically connected, which may contribute to early memory decline.

Subjective memory measures: Metamemory questionnaires currently in use

Subjective memory evaluation is important for assessing memory abilities and complaints alongside objective measures. In research and clinical settings, questionnaires are used to examine perceived memory ability, memory complaints, and memory beliefs/knowledge. Although they provide a structured measure of self-reported memory, there is some debate as to whether subjective evaluation accurately reflects memory abilities. Specifically, the disconnect between subjective and objective memory measures remains a long-standing issue within the field. Thus, it is essential to evaluate the benefits and limitations of questionnaires that are currently in use. This review encompasses three categories of metamemory questionnaires: self-efficacy, complaints, and multidimensional questionnaires. Factors influencing self-evaluation of memory including knowledge and beliefs about memory, ability to evaluate memory, recent metamemory experiences, and affect are examined. The relationship between subjective and objective memory measures is explored, and considerations for future development and use of metamemory questionnaires are provided.

Factors influencing patient-provider communication about subjective cognitive decline in people with COPD: Insights from a national survey

Objective: While there is a growing body of evidence indicating a relationship between COPD and cognitive impairment, there is a gap in evidence regarding discussions of cognitive symptoms in healthcare settings. This study investigated the extent to which individuals with Chronic Obstructive Pulmonary Disease (COPD) and Subjective Cognitive Decline (SCD) self-reported confusion or memory loss with healthcare professionals. Methods: A secondary analysis of 2019 BRFSS data of US adults aged 45+ with COPD (N = 107,204), using logistic regression to explore associations between socio-demographic and health-related indicators with discussion of cognitive symptoms with healthcare professionals. Results: Less than half (45.88%) of individuals reporting SCD discussed their cognitive symptoms with their healthcare provider. In the adjusted model, unemployed (AOR = 2.92, 95% CI: 1.70-5.02, p < .005), retired (AOR = 3.16, 95% CI: 1.37-7.30, p < .01), and current smokers (AOR = 1.73, 95% CI: 1.02-2.93, p < .05) were more likely to discuss cognitive decline with a healthcare professional than their counterparts. In contrast, males (AOR = 0.53, 95% CI: 0.32-0.86, p < .05) and binge drinkers (AOR = 0.49, 95% CI: 0.30-0.79, p < .01) were significantly less likely to do so when compared to their counterparts. Discussion: The study highlighted significant disparities in the likelihood of individuals with COPD discussing cognitive symptoms based on socio-demographic and health risk behaviors. Conclusion: Addressing gender disparities, occupational status, and personal health risks is crucial for improving patient-provider communication about SCD among adults with COPD.

Subjective Complaints are Similar in Subjective Cognitive Decline and Early-Stage Alzheimer's Disease when Assessed in a Memory Clinic Setting

BACKGROUND

Subjective cognitive complaints are generally poorly associated with objective memory functioning in older persons. Subjective cognitive decline (SCD) is a key feature in SCD and amnestic mild cognitive impairment (aMCI) which both can represent early Alzheimer's disease (AD). The aim of this study was to assess how memory clinic patients with SCD, MCI and mild AD dementia scored on 3 different complaint measures and if the format of assessment had an impact on the association with cognitive functioning, age, and depressive symptoms.

METHODS

We included 17 SCD patients, 17 aMCI patients, 17 patients with mild AD, and 30 controls. Complaints were assessed with the Cognitive Change Index (CCI), the Subjective Memory Complaints (SMC) scale, and the Memory Complaint Questionnaire (MAC-Q).

RESULTS

There were no significant differences between the total scores in the patient groups on the questionnaires. However, significant differences were found in the number of patients classified with impairment when using the CCI, the SMC, and the MAC-Q. Scores on all questionnaires were significantly associated with depressive symptoms, and significant associations with age, gender, and Addenbrookes Cognitive Examination score were found for the SMC. In patients with cognitive dysfunction, lower memory awareness significantly predicted fewer cognitive complaints.

CONCLUSIONS

SCD patients in a memory clinic setting report the same degree of cognitive impairment as patients with aMCI and mild dementia, and in a hospital-based cohort we extend previous findings from healthy controls, that definition of SCD may depend on the format of assessment.

The Role of Cognitive Self-Report Measure Type in Predicting Cognitive Decline Among Older Adults: A Systematic Review

Many types of items are used to measure self-reported cognition, resulting in heterogeneity across studies. Certain cognitive self-report measure types may be more predictive of future decline. Therefore, the purpose of this systematic review was to compare whether specific types of cognitive self-report measures better predict risk for cognitive decline over time when measures are directly compared within the same study. The PRISMA criteria guided the review. Eligibility criteria included: longitudinal studies, outcome of cognitive decline, at least 2 different cognitive self-report measures, and no cognitive impairment at baseline. Nineteen studies were included in the final review. A narrative synthesis of results was completed, resulting in 3 thematic groups of comparisons across self-reported measure types. Self-reported memory decline with worry and peer perceptions of memory were associated with the highest risk for cognitive decline. Future longitudinal investigations of self-reported cognitive problems should focus on using measures that may be most sensitive to predicting cognitive decline risk.

The Impact of COVID-19 Infection on Cognitive Function and the Implication for Rehabilitation: A Systematic Review and Meta-Analysis

There is mounting evidence that patients with severe COVID-19 disease may have symptoms that continue beyond the acute phase, extending into the early chronic phase. This prolonged COVID-19 pathology is often referred to as ‘Long COVID’. Simultaneously, case investigations have shown that COVID-19 individuals might have a variety of neurological problems. The accurate and accessible assessment of cognitive function in patients post-COVID-19 infection is thus of increasingly high importance for both public and individual health. Little is known about the influence of COVID-19 on the general cognitive levels but more importantly, at sub-functions level. Therefore, we first aim to summarize the current level of evidence supporting the negative impact of COVID-19 infection on cognitive functions. Twenty-seven studies were included in the systematic review representing a total of 94,103 participants (90,317 COVID-19 patients and 3786 healthy controls). We then performed a meta-analysis summarizing the results of five studies (959 participants, 513 patients) to quantify the impact of COVID-19 on cognitive functions. The overall effect, expressed in standardized mean differences, is −0.41 [95%CI −0.55; −0.27]. To prevent disability, we finally discuss the different approaches available in rehabilitation to help these patients and avoid long-term complications.

Evaluation of Processing Speed of Different Cognitive Functions Across the Life Span Using Cognitive Mobile Games

Objective: Processing speed (PS) is an important indicator of cognitive functioning and normal aging. However, the tools used to evaluate these are often rather simplistic and only assess one cognitive component. The aim of this study was to use cognitive mobile games (CMG) to evaluate the evolution of reaction times over the life span during different cognitive tasks. Methodology: We carried out a retrospective observational study in which we obtained anonymized results of 15,000 subjects. Scores of five CMG that train arithmetic, vocabulary, response control, visual attention and recognition, and working memory were analyzed. Results: Overall, we observed a highly statistically significant decrease (P < 0.001) in PS and a decrease of accuracy (P < 0.001) with increasing participant age, indicating that for each cognitive function tested, older participants performed cognitive tasks more slowly than younger participants. We also observed an interaction between the age of the participants and the number of errors. These results are consistent with physiological data with respect to aging and cognition. Conclusion: Owing to their wide availability and ease of use, CMG could be used as a simple tool to monitor cognitive function such as PS. Further studies are needed to study the influence of pathologies on those variables.

Regional brain atrophy and cognitive decline depend on definition of subjective cognitive decline

Background

People with subjective cognitive decline (SCD) may be at increased risk for Alzheimer’s disease (AD). However, not all studies have observed this increased risk. This project examined whether four common methods of defining SCD yields different patterns of atrophy and future cognitive decline between cognitively normal older adults with (SCD+ ) and without SCD (SCD−).

Methods

Data from 273 Alzheimer’s Disease Neuroimaging Initiative cognitively normal older adults were examined. To operationalize SCD we used four common methods: Cognitive Change Index (CCI), Everyday Cognition Scale (ECog), ECog + Worry, and Worry. Voxel-based logistic regressions were applied to deformation-based morphology results to determine if regional atrophy between SCD− and SCD+ differed by SCD definition. Linear mixed-effects models were used to evaluate differences in future cognitive decline.

Results

Results varied between the four methods of defining SCD. Left hippocampal grading was more similar to AD in SCD+ than SCD− when using the CCI (p = .041) and Worry (p = .021) definitions. The right (p=.008) and left (p=.003) superior temporal regions had smaller volumes in SCD+ than SCD−, but only with the ECog. SCD+ was associated with greater future cognitive decline measured by Alzheimer’s Disease Assessment Scale, but only with the CCI definition. In contrast, only the ECog definition of SCD was associated with future decline on the Montreal Cognitive Assessment.

Conclusion

These findings suggest that the various methods used to differentiate between SCD− and SCD+ influence whether volume differences and findings of cognitive decline are observed between groups in this retrospective analysis.

Brain training using cognitive apps can improve cognitive performance and processing speed in older adults

Managing age-related decrease of cognitive function is an important public health challenge, especially in the context of the global aging of the population. Over the last years several Cognitive Mobile Games (CMG) have been developed to train and challenge the brain. However, currently the level of evidence supporting the benefits of using CMG in real-life use is limited in older adults, especially at a late age. In this study we analyzed game scores and the processing speed obtained over the course of 100 sessions in 12,000 subjects aged 60 to over 80 years. Users who trained with the games improved regardless of age in terms of scores and processing speed throughout the 100 sessions, suggesting that old and very old adults can improve their cognitive performance using CMG in real-life use.

Memory awareness in patients with Major Depressive Disorder

BACKGROUND

Subjective Memory Complaints (SMC) along with cognitive deficits are frequently observed in patients with Major Depressive Disorder (MDD). The relationship between SMC and objective memory performance in patients with MDD was evaluated, in comparison with patients with Mild Cognitive Impairment due to Alzheimer's Disease (MCI-AD) and healthy controls (HC).

METHODS

Patients with MDD (n = 47), MCI-AD (n = 43) and HC (n = 45) were assessed with a self-report memory complaints scale (SMCS) and underwent a comprehensive clinical and neuropsychological assessment. A discrepancy score between the Logical Memory delayed recall and the SMCS total score was calculated as a measure of memory awareness.

RESULTS

Patients with MDD (12.5 ± 4.4) and patients with MCI-AD (10.9 ± 4.1) had not significantly different SMCS total scores, whereas HC showed significantly lower scores (4.0 ± 3.0). As much as 74.5% of patients with MDD patients and 65.1% of patients with MCI-AD reported prominent memory complaints, whereas only 4.4% of HC did. Patients with MDD had relatively preserved memory tests, resulting in a higher discrepancy score than both patients with MCI-AD and HC. The SMCS total score correlated positively with depressive symptoms in the 3 groups of participants.

CONCLUSIONS

Patients with MDD showed inaccurate memory self-awareness as they under-estimated their memory functioning, a pattern distinct from both patients with MCI-AD and HC.

How Well Does Subjective Cognitive Decline Correspond to Objectively Measured Cognitive Decline? Assessment of 10-12 Year Change

BACKGROUND

Although not strongly correlated with current objective cognitive ability, subjective cognitive decline (SCD) is a risk factor for Alzheimer's disease. Most studies focus on SCD in relation to future decline rather than objective prior decline that it purportedly measures.

OBJECTIVE

We evaluated whether self-report of cognitive decline-as a continuous measure-corresponds to objectively-assessed episodic memory and executive function decline across the same period.

METHODS

1,170 men completed the Everyday Cognition Questionnaire (ECog) at mean age 68 assessing subjective changes in cognitive ability relative to 10 years prior. A subset had mild cognitive impairment (MCI), but MCI was diagnosed without regard to subjective decline. Participants completed up to 3 objective assessments of memory and executive function (M = 56, 62, and 68 years). Informant-reported ECogs were completed for 1,045 individuals. Analyses controlled for depression and anxiety symptoms assessed at mean age 68.

RESULTS

Participant-reported ECog scores were modestly associated with objective decline for memory (β= -0.23, 95%CI [-0.37, -0.10]) and executive function (β= -0.19, 95%CI [-0.33, -0.05]) over the same time period. However, these associations were nonsignificant after excluding MCI cases. Results were similar for informant ratings. Participant-rated ECog scores were more strongly associated with concurrent depression and anxiety symptoms, (β= 0.44, 95%CI [0.36, 0.53]).

CONCLUSION

Continuous SCD scores are correlated with prior objective cognitive changes in non-demented individuals, though this association appears driven by individuals with current MCI. However, participants' current depression and anxiety ratings tend to be strongly associated with their SCD ratings. Thus, what primarily drives SCD ratings remains unclear.

Differences in the Associations Between Memory Complaints and Depressive Symptoms Among Black and White Older Adults

OBJECTIVE

To test whether race (specifically Black or White) moderates the relationship between memory complaints and depressive symptoms in cognitively normal older adults, and if these relationships vary by memory complaint characteristics.

METHODS

Data from Black (n = 551) and White (n = 1,158) cognitively intact participants (Mage = 77.1, SD = 7.5; 76.6% female) in the Minority Aging Research Study and the Rush Memory and Aging Project were used. Participants completed annual clinical evaluations, including the Center for Epidemiologic Studies Depression scale and two memory complaint questions, over periods of up to 18 years. Ordinal mixed effects models were used to examine within-person relationships between memory complaints and depressive symptoms over time, as well as whether race moderated these associations.

RESULTS

Reports of greater memory change over time were associated with more depressive symptoms for both Black and White older adults. However, reports of greater frequency of memory problems were related to depressive symptoms for Black older adults only.

CONCLUSION

Findings suggest differential associations between memory complaints and depressive symptoms in cognitively normal Black and White older adults and call for future research to examine the influence of race and related factors on memory complaints and depressive symptoms.

Barriers to help-seeking for memory problems in older adults

Aim

The aim of this study was to investigate potential barriers to help-seeking for memory problems as well as outreach to providers.

Findings

Participants who endorsed having hearing problems were the most likely to endorse barriers to help-seeking as well as speaking to a physician.

Message

Physicians and healthcare agencies can work to design outreach for persons who experience barriers, particularly hearing loss.

Purpose

Early detection of age- and disease-related cognitive problems affords patients the opportunities to receive medical treatment, engage in research, and plan for the future. Understanding help-seeking behavior has potential to aid both patients and clinicians. This study was designed to identify predictors of endorsed barriers to memory-related help-seeking as well as medical help-seeking endorsement.

Methods

This cross-sectional correlational study used a convenience sample of 97 older adults. The participants answered anonymous questionnaires about subjective memory, mood, and health and several items designed to investigate help-seeking for memory issues.

Results

Persons who endorsed multiple barriers to help-seeking were more likely to also endorse having hearing problems. In addition, participants who reported that they would not talk to a doctor or physician about memory concerns also had significantly worse subjective hearing.

Conclusion

Hearing loss may be a particular risk for not seeking help for memory problems. Physicians and healthcare agencies can work to design outreach for persons who experience barriers, such as hearing loss and the concomitant outcomes.

Age-Associated Capacity to Progress When Playing Cognitive Mobile Games: Ecological Retrospective Observational Study

Background

The decline of cognitive function is an important issue related to aging. Over the last few years, numerous mobile apps have been developed to challenge the brain with cognitive exercises; however, little is currently known about how age influences capacity for performance improvement when playing cognitive mobile games.

Objective

The objective of this study was to analyze the score data of cognitive mobile games over a period of 100 gaming sessions to determine age-related learning ability for new cognitive tasks by measuring the level of score improvement achieved by participants of different ages.

Methods

Scores from 9000 individuals of different ages for 7 cognitive mobile games over 100 gaming sessions were analyzed. Scores from the first session were compared between age groups using one-way analysis of variance. Mixed models were subsequently used to investigate the progression of scores over 100 sessions.

Results

Statistically significant differences were found between age groups for the initial scores of 6 of the 7 games (linear trend, P<.001). Cognitive mobile game scores increased for all participants (P<.001) suggesting that all participants were able to improve their performance. The rate of improvement was, however, strongly influenced by the age of the participant with slower progression for older participants (P<.001).

Conclusions

This study provides evidence to support two interesting insights—cognitive mobile game scores appear to be sensitive to the changes in cognitive ability that occur with advancing age; therefore, these games could be a convenient way to monitor cognitive function over long-term follow-up, and users who train with the cognitive mobile games improve regardless of age.

Subjective Cognitive Decline and Related Cognitive Deficits

Since late stage dementia, including Alzheimer's disease (AD), cannot be reversed by any available drugs, there is increasing research interest in the preclinical stage of AD, i.e., subjective cognitive decline (SCD). SCD is characterized by self-perceptive cognitive decline but is difficult to detect using objective tests. At SCD stage, the cognitive deficits can be more easily reversed compared to that of mild cognitive impairment (MCI) and AD only if accurate diagnosis of SCD and early intervention can be developed. In this paper, we review the recent progress of SCD research including current assessment tools, biomarkers, neuroimaging, intervention and expected prognosis, and the potential relevance to traumatic brain injury (TBI)-induced cognitive deficits.

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.

Risk Factors and Neuropsychological Assessments of Subjective Cognitive Decline (plus) in Chinese Memory Clinic

Background

Since subjective cognitive decline (SCD) was standardized in 2014, many studies have investigated its features. However, the risk of SCD (plus) progressing to AD is much higher, and yet there have been few studies reporting the risk factors and neuropsychological assessment characteristics of SCD (plus).

Objective

To characterize SCD (plus) by comparing it with normal control (NC), amnesic mild cognitive impairment (aMCI), and Alzheimer Disease (AD) regarding their demographics, lifestyle, family history of dementia, multimorbidity and the neuropsychological assessments.

Methods

A total of 135 participants were recruited, including 23 NC, 30 SCD (plus), 45 aMCI and 37 AD. Descriptive statistics were provided. A logistic regression model was used to analyze the affecting factors of SCD (plus), and finally the Receiver Operating Characteristic (ROC) analysis was applied to distinguish between SCD (plus) and NC.

Results

(1) SCD (plus) group was younger than both the aMCI group and AD group. It consisted of more participants with mental work and higher body mass index (BMI) than the AD group. (2) Scores of Auditory Verbal Learning Test - Immediate recall (AVLT-IR) and AVLT-Long delayed recall (AVLT-LR) decreased in the following order: NC→SCD (plus)→aMCI→AD. (3) The Area Under Curve (AUC) for discriminating SCD (plus) and NC group was from 0.673 to 0.838.

Conclusion

Aging is an important risk factor of both NC progressing to SCD (plus), and SCD (plus) progressing to aMCI or AD. In addition to aging, lower education level and lower BMI were significantly associated with greater odds of SCD (plus) progressing to aMCI or AD patients, whereas mental work was a protective factor of SCD (plus) progressing to AD. Finally, AVLT is a sensitive indicator of the cognitive decline and impairment in SCD (plus) in relative to normal controls.

The Relationship between Subjective Cognitive Impairment and Activity Participation: A Systematic Review

This systematic review synthesizes current evidence to determine how subjective cognitive impairment (SCI) relates to physical, cognitive, and social activity participation in older adults. Nine peer-reviewed articles were reviewed and appraised for evidence quality. Most were cross-sectional and had high methodological quality. Higher levels of SCI were almost universally associated with lower levels of physical and social activity participation. These findings suggest that older adults who report higher SCI engage in fewer activities. Examining these relationships longitudinally is an important next step to determine whether SCI precedes withdrawing from activities in older adults.

The Use of Mobile Games to Assess Cognitive Function of Elderly with and without Cognitive Impairment

BACKGROUND

In the past few years numerous mobile games have been developed to train the brain. There is a lack of information about the relation between the scores obtained in these games and the cognitive abilities of the patients.

OBJECTIVE

The aim of this study was to determine whether or not mobile games can be used to assess cognitive abilities of elderly.

METHODS

Twenty healthy young adults, 29 old patients with cognitive impairments (Mini-Mental State Exam (MMSE) [20- 24]) and 27-aged controls participated in this study. Scores obtained in 7 mobile games were correlated with MMSE and the Addenbrooke's Cognitive Evaluation revised (ACE-R).

RESULTS

Statistically significant differences were found for all games between patients with cognitive impairments and the aged controls. Correlations between the average scores of the games and the MMSE and ACE-R are significant (R = 0.72 [p < 0.001] and R = 0.81 [p < 0.001], respectively).

CONCLUSION

Scores of cognitive mobile games could be used as an alternative to MMSE and ACE-R to evaluate cognitive function of aged people with and without cognitive impairment at least when MMSE is higher than 20/30.

Subjective cognitive decline: preclinical manifestation of Alzheimer's disease

Subjective cognitive decline (SCD), characterized by a very early and subtle cognitive decline prior to the appearance of objective cognitive impairment, is considered to be the preclinical manifestation of Alzheimer's disease (AD). Given the lack of significant abnormalities in standardized neuropsychological assessments for individuals with SCD, biochemical and neuroimaging biomarkers may be important indicators of the preclinical stage of AD. The application of various biomarkers derived from the cerebrospinal fluid and neuroimaging thus has the potential to make AD-related pathology detectable in vivo. In this review, we discuss the conceptual evolution of SCD as an entity and further elucidate characteristic cerebrospinal fluid and neuroimaging biomarkers of SCD.

Prevalence, Risk Factors, and Complaints Screening Tool Exploration of Subjective Cognitive Decline in a Large Cohort of the Chinese Population

BACKGROUND

Substantial studies have reported the prevalence and the affecting factors of subjective cognitive decline (SCD). The complaints screening scale has also been used for probing. However, little is known in China.

OBJECTIVE

To investigate the prevalence and risk factors of SCD, and explore an SCD complaints screening scale in China.

METHODS

Stratified cluster random sampling was conducted. 2,689 residents aged 60-80 years completed questionnaire 1. 814 residents were included for clinical and neuropsychological evaluations. Two standards were used to make the diagnosis of mild cognitive impairment (MCI) and SCD, and a preliminary screening rate comparison was carried out. Finally, we assessed the risk factors of SCD and the correlation between the SCD-questionnaire 9 (SCD-Q9) and the Auditory Verbal Learning Test-Long Delay Free Recall (AVLT-LR).

RESULTS

1) Standard 1 (ADNI2): the prevalence of SCD was 18.8% (95% CI = 14.7-22.9%) and zero conformed to six criteria (SCD plus). 2) Standard 2 (Jak/Bondi): the prevalence of SCD was 14.4% (95% CI = 10.7-18.1%). 3) Standard 1 had a relatively higher "false" positive rate, whereas Standard 2 had higher "false" negative rate. 4) Age, low education, fewer close friends, and daily drinking were independent risk factors for SCD progressing to MCI. 5) Total points of SCD-Q9 were negatively correlated to the value of AVLT-LR.

CONCLUSIONS

The prevalence of SCD is high in the ShunYi District in Beijing, China. Age, low education, less social support, and daily drinking are independent risk factors. The brief SCD-Q9 can be used as a reference.

Plasma cytokine IL-6 levels and subjective cognitive decline: preliminary findings

OBJECTIVE

Detection of Alzheimer's disease (AD) prior to clinical inception will be paramount for introducing disease modifying treatments. We have begun collecting baseline characteristics of a community cohort for longitudinal assessment and testing of antecedent blood-based biomarkers. We describe the baseline visit from the first 131 subjects in relationship to a commonly described cytokine, interleukin 6 (IL-6).

METHODS

Subjects from the community presented for a free memory screening with varying degrees of memory concern. We quantified the baseline plasma levels of the cytokine IL-6 and assessed cognition (Montreal Cognitive Assessment, MoCA) and mood (Geriatric Depression Scale, GDS) in relationship to their memory concern.

RESULTS

Baseline MoCA scores were inversely related to age, and this association was influenced by an AD risk factor, Apolipoprotein E (APOE4) carrier status. The degree of subjective cognitive decline correlated with GDS and was inversely related to MoCA scores. Interleukin 6 levels were related to age, body mass index, and years of education.

CONCLUSIONS

It will be important to assess how these baseline IL-6 levels and forthcoming novel biomarkers relate to future cognitive decline. Copyright © 2017 John Wiley & Sons, Ltd.

From mild cognitive impairment to subjective cognitive decline: conceptual and methodological evolution

Identification of subjects at the early stages of Alzheimer's disease (AD) is fundamental for drug development and possible intervention or prevention of cognitive decline. The concept of mild cognitive impairment (MCI) evolved during the past two decades to define subjects at the transitional stage between normal aging and dementia. Evidence from cross-sectional and longitudinal studies has shown that MCI is associated with an increased risk of positive AD biomarkers and an increased annual conversion rate of 5%-17% to AD. The presence of AD biomarkers in subjects with MCI was associated with an even higher risk of progression to dementia. However, earlier clinical trials for pharmacotherapy in subjects with MCI were disappointing. To extend the spectrum of AD to an earlier stage before MCI, subjective cognitive decline (SCD) was introduced and was defined as self-reported cognitive decline before the deficits could be detected by cognitive tests. Subjects with SCD have an increased risk of underlying AD pathology. However, SCD can also develop secondary to other heterogeneous etiologies, including other neurodegenerative and psychiatric diseases, personality traits, physical conditions, and medication use. Several clinical and biomarker features were proposed to predict risk of conversion to AD in subjects with SCD. Further longitudinal studies are needed to support the validity of these high-risk features.

Subjective cognitive decline: The first clinical manifestation of Alzheimer's disease?

Background

Mild cognitive impairment is considered as the first clinical manifestation of Alzheimer's disease (AD), when the individual exhibits below performance on standardized neuropsychological tests. However, some subjects before having a lower performance on cognitive assessments already have a subjective memory complaint.

Objective

A review about subjective cognitive decline, the association with AD biomarkers and risk of conversion to dementia.

Methods

We performed a comprehensive non-systematic review on PubMed. The keywords used in the search were terms related to subjective cognitive decline.

Results

Subjective cognitive decline is characterized by self-experience of deterioration in cognitive performance not detected objectively through formal neuropsychological testing. However, various terms and definitions have been used in the literature and the lack of a widely accepted concept hampers comparison of studies. Epidemiological data have shown that individuals with subjective cognitive decline are at increased risk of progression to AD dementia. In addition, there is evidence that this group has a higher prevalence of positive biomarkers for amyloidosis and neurodegeneration. However, Alzheimer's disease is not the only cause of subjective cognitive decline and various other conditions can be associated with subjective memory complaints, such as psychiatric disorders or normal aging. The features suggestive of a neurodegenerative disorder are: onset of decline within the last five years, age at onset above 60 years, associated concerns about decline and confirmation by an informant.

Conclusion

These findings support the idea that subjective cognitive complaints may be an early clinical marker that precedes mild cognitive impairment due to Alzheimer's disease.