BACKGROUND: Subjective cognitive decline (SCD) is considered a pre-symptomatic stage of dementia characterized by cognitive complaints. The ability of education to reduce the risk of dementia is well known. Our objective is to investigate the influence of education on the risk of progression from SCD to MCI or dementia.
METHODS: Prospective longitudinal studies of adults (≥50 years) with SCD evaluating progression to objective cognitive decline, MCI, or dementia were selected. Pooled estimates (random effects model) and 95 % confidence intervals were calculated, exploring heterogeneity. Standardized education differences, Odds Ratio, or Hazard Ratio between converters and non-converters were estimated.
RESULTS: The systematic review carried out showed that high education, as well as other cognitive reserve proxies, delays cognitive decline. The first meta-analysis showed a significant association of SCD with conversion in both high and low education strata. A second meta-analysis considering education as a continuous variable found that SCD converters showed two years less education than non-converters.
CONCLUSIONS: Our results suggest that education has a delaying effect against cognitive decline progression. The presumed improvement in accurately detecting cognitive decline associated with better metacognitive skills in higher-educated SCD participants does not seem to neutralize the incremental risk of objective cognitive decline associated with lower educational attainment.

UNASSIGNED: This study investigated the relationship between older adults\' expectations regarding aging and subjective cognition. Specifically, we examined whether the three domains of aging expectations (physical health, mental health, and cognitive function) were associated with two aspects of subjective cognition: current subjective cognition and subjective cognitive decline (SCD).
UNASSIGNED: An online survey was conducted among U.S. adults aged 65-90 (N = 581; Mage=71.4, SD ± 4.81; 51% female). Measures included the 12-item Expectations Regarding Aging scale, the 8-item PROMIS Cognitive Abilities scale (current subjective cognition), and the 12-item Everyday Cognition scale (SCD). We used generalized linear models to examine associations between overall aging expectations and its three domains with current subjective cognition ratings and SCD.
UNASSIGNED: We found that more positive expectations regarding physical health, mental health, and cognitive function in aging were associated with higher ratings of current subjective cognition as well as lower SCD. The magnitude of effects across aging expectations domains were similar for both aspects of subjective cognition.
UNASSIGNED: Aging expectations are malleable and influence an individual\'s perceptions of their cognitive functioning. Modifying older adults\' aging expectations could support healthier cognitive aging through increased awareness and accurate assumptions about the aging process.

BACKGROUND: The potential utility of subjective cognitive decline (SCD) as an early risk marker of Alzheimer\'s disease and related dementias is under consideration. We examined associations between SCD and cognitive change among middle-aged and older Hispanic/Latino adults living in the United States.
METHODS: The short-form Everyday Cognition Scale (ECog-12) was assessed to generate global, executive function, and memory-related SCD scores. We used survey generalized regressions to model the change in learning, memory, verbal fluency, executive function, and global cognitive performance over 7 years as a function of SCD (at Visit 2).
RESULTS: The mean age was 56.37 ± 8.10 years at Visit 1 (n = 6225). Higher ECog-12 was associated with greater decline in global cognitive performance (ECog-12 global: B = -0.17, standard error [SE] = 0.02; ECog-12 executive: B = -0.15, SE = 0.02; ECog-12 memory: B = -0.14, SE = 0.02, p\'s < 0.001).
CONCLUSIONS: These results support the link between subjective reports of cognitive decline and objectively measured 7-year cognitive decline in community-dwelling, middle-aged, and older Hispanic/Latino adults.
CONCLUSIONS: We found that nearly two-thirds of diverse middle-aged and older Hispanics/Latinos reported cognitive concerns in a large and representative population study. Self-reported subjective experiences of cognitive decline reflect objective cognitive decline in US Hispanics/Latinos. The relationship is stronger among men compared to women. The relationship between subjective and objective changes to memory are stronger in those with cognitive concerns, and remain even in cognitively healthy individuals.

Objectives: Examine whether physical activity (PA) changes during the COVID-19 pandemic were related to subjective cognitive decline (SCD), depression, and anxiety in older adults and whether these varied by sociodemographic variables. Methods: 301 older adults completed an online survey between May and October 2020 and 3 months later, including self-report questionnaires of SCD, depression, and anxiety. PA changes were determined with a question. Results: 60% of participants reported decreased PA. Those who reduced their PA were more likely to be from low to middle income and younger. PA increase was related to less SCD and depressive symptoms compared to those who decreased it. Participants who maintained their PA had fewer SCD concerns, depressive, and anxiety symptoms than those who decreased it. Discussion: Reducing PA was associated with worse neuropsychiatric and cognitive symptoms. Encouraging older adults to increase PA may help mitigate some of the pandemic\'s adverse effects on psychological well-being.

UNASSIGNED: Subjective Cognitive Decline (SCD) refers to self-reported cognitive decline with normal global cognition. This study aimed to capture SCD among low educated patients with Parkinson\'s disease (PD) using a newly established indicator.
UNASSIGNED: We recruited 64 PD patients with low education levels (education ≤12 years) for the study. The presence of SCD was determined based on a Unified Parkinson\'s Disease Rating Scale Part I (1.1) score ≥ 1. Spearman analysis and multivariate binary logistic regression analyses were conducted to investigate factors associated with the PD-SCD group. The receiver operating characteristic (ROC) curve was used to evaluate the sensitivity and specificity of the new combined index.
UNASSIGNED: The prevalence of SCD in PD patients was 43.75%. Low educated PD-SCD patients had higher scores on the Non-Motor Symptoms Scale (NMSS), Parkinson\'s Fatigue Scale (PFS), Epworth Sleepiness Scale (ESS), as well as higher scores on the UPDRS-I and UPDRS-II, compared to PD patients without SCD. They also demonstrated poorer performance on the Montreal Cognitive Assessment (MoCA), particularly in the domains of executive abilities/attention/language. Multivariate binary regression confirmed the significant association between PD-SCD and MoCA-executive abilities/attention/language. Based on these findings, a combined index was established by summing the scores of MoCA-executive abilities, MoCA-attention, and MoCA-language. ROC analysis showed that the combined index could differentiate PD-SCD patients with an area under the curve (AUC) of 0.876. A score of 12 or less on the combined index had a sensitivity of 73.9% and a specificity of 76.2% for diagnosing PD-SCD.
UNASSIGNED: These low education patients with PD-SCD may exhibit potential PD-related pathological changes. It is important for clinicians to identify PD-SCD patients as early as possible. The newly combined index can help capture these low educated PD-SCD patients, with an AUC of 0.867, and is expected to assist clinicians in earlier identification and better management of PD patients.

UNASSIGNED: A range of imaging modalities have reported Alzheimer\'s disease-related abnormalities in individuals experiencing subjective cognitive decline (SCD). However, there has been no consistent local abnormality identified across multiple neuroimaging modalities for SCD.
UNASSIGNED: We aimed to investigate the convergent local alterations in amyloid-β (Aβ) deposition, glucose metabolism, and resting-state functional MRI (RS-fMRI) metrics in SCD.
UNASSIGNED: Fifty SCD patients (66.4±5.7 years old, 19 men [38%]) and 15 normal controls (NC) (66.3±4.4 years old, 5 men [33.3%]) were scanned with both [18F]-florbetapir PET and [18F]-fluorodeoxyglucose PET, as well as simultaneous RS-fMRI from February 2018 to November 2018. Voxel-wise metrics were retrospectively analyzed, including Aβ deposition, glucose metabolism, amplitude of low frequency fluctuation (ALFF), regional homogeneity (ReHo), and degree centrality(DC).
UNASSIGNED: The SCD group showed increased Aβ deposition and glucose metabolism (p < 0.05, corrected), as well as decreased ALFF, ReHo, and DC (p < 0.05, uncorrected) in the left dorsal precuneus (dPCu). Furthermore, the dPCu illustrated negative resting-state functional connectivity with the default mode network. Regarding global Aβ deposition positivity, the Aβ deposition in the left dPCu showed a gradient change, i.e., Aβ positive SCD > Aβ negative SCD > Aβ negative NC. Additionally, both Aβ positive SCD and Aβ negative SCD showed increased glucose metabolism and decreased RS-fMRI metrics in the dPCu.
UNASSIGNED: The dorsal precuneus, an area implicated in early AD, shows convergent neuroimaging alterations in SCD, and might be more related to other cognitive functions (e.g., unfocused attention) than episodic memory.

UNASSIGNED: Individuals with subjective cognitive decline (SCD) express concern about self-perceived cognitive decline despite no objective impairment and are at higher risk of developing Alzheimer\'s disease. Despite documented links between SCD and repetitive negative thinking (RNT), the specific impact of RNT on brain integrity and cognition in exacerbating the SCD condition remains unclear. We aimed to investigate the influence of RNT on global cognition and brain integrity, and their interrelationships among healthy middle-aged and older adults experiencing SCD.
UNASSIGNED: Out of 616 individuals with neuroimaging and neuropsychological data available, 89 (mean age = 56.18 years; 68.54% females) met SCD criteria. Eighty-nine non-SCD individuals matched by age, sex, and education were also selected and represented the control group (mean age = 56.09 years; 68.54% females). Global cognition was measured using the preclinical Alzheimer\'s cognitive composite (PACC5), which includes dementia screening, episodic memory, processing speed, and category fluency tests. RNT was calculated through three questionnaires assessing intrusive thoughts, persistent worry, and rumination. We generated cortical thickness (CTh) maps and quantified the volume of white matter lesions (WML) in the whole brain, as grey and white matter integrity measures, respectively.
UNASSIGNED: SCD individuals exhibited higher RNT scores, and thinner right temporal cortex compared to controls. No differences were observed in PACC5 and WML burden between groups. Only the SCD group demonstrated positive associations in the CTh-PACC5, CTh-RNT, and WML-RNT relationships.
UNASSIGNED: In this cross-sectional study, RNT was exclusively associated with brain integrity in SCD. Even though our findings align with the broader importance of investigating treatable psychological factors in SCD, further research may reveal a modulatory effect of RNT on the relationship between cognition and brain integrity in SCD.

BACKGROUND: Subjective cognitive decline (SCD) is prevalent in community-dwelling (pre)frail older adults. This study aimed to investigate whether baseline subjective cognitive decline (SCD) and mild cognitive impairment (MCI) impacted the effectiveness of an exercise intervention among (pre)frail older adults.
METHODS: This is a post hoc analysis of a stepped-wedge cluster randomized trial among (pre)frail older adults across six communities. The intervention effectiveness was examined among (pre)frail older people among subgroups with normal cognition (n = 44), SCD (n = 58), or MCI (n = 30).
RESULTS: The normal cognition group had both immediate and persistent treatment responses to most outcomes. The SCD group showed positive responses to frailty (0-, 12-, 24 week), ambulation and dynamic balance (0-week), and depressive symptoms (12-week). The MCI group exhibited immediate improvement in frailty, cognition, depressive symptoms, social support and QoL, which persisted only in frailty status, social support and mental QoL at follow-ups. The MCI group showed superior immediate responses to cognitive function and depressive symptoms compared to another two subgroups. No differences were found between the normal cognition and SCD groups except for cognitive status (12-week).
CONCLUSIONS: (Pre)frail people with SCD or MCI had fewer improved outcomes compared to those with normal cognition regardless of immediate or persistent improvements. The incorporation of cognitive strategies with exercise interventions are recommended among (pre)frail older adults with SCD or MCI.

Subjective cognitive decline (SCD) is a high-risk population in the preclinical stage of Alzheimer\'s disease (AD), and olfactory dysfunction is a risk factor for dementia progression. The present study aimed to explore the patterns of functional connectivity (FC) changes in the olfactory neural circuits during olfactory stimulation in SCD subjects. A total of 56 SCD subjects and 56 normal controls (NCs) were included. All subjects were assessed with a cognitive scale, an olfactory behavior test, and olfactory task-based functional magnetic resonance imaging scanning. The FC differences in olfactory neural circuits between the two groups were analyzed by the generalized psychophysiological interaction. Additionally, we calculated and compared the activation of brain regions within the olfactory neural circuits during odor stimulation, the volumetric differences in brain regions showing FC differences between groups, and the correlations between neuroimaging indicators and olfactory behavioral and cognitive scale scores. During odor stimulation, the FC between the bilateral primary olfactory cortex (bPOC) and the right hippocampus in the SCD group was significantly reduced; while the FC between the right hippocampus and the right frontal cortex was significantly increased in the SCD group. The bPOC of all subjects showed significant activation, but no significant difference in activation between groups was found. No significant differences were observed in the volume of the brain regions within the olfactory neural circuits or in olfactory behavior between groups. The volume of the bPOC and right frontal cortex was significantly positively correlated with olfactory identification, and the volume of the right frontal cortex and right hippocampus was significantly correlated with cognitive functions. Furthermore, a significant correlation between the activation of bPOC and the olfactory threshold was found in the whole cohort. These results suggested that while the structure of the olfactory neural circuits and olfactory behavior in SCD subjects remained stable, there were significant changes observed in the FC of the olfactory neural circuits (specifically, the POC-hippocampus-frontal cortex neural circuits) during odor stimulation. These findings highlight the potential of FC alterations as sensitive imaging markers for identifying high-risk individuals in the early stage of AD.

BACKGROUND: Polygenic risk scores (PRS) and subjective cognitive decline (SCD) are associated with the risk of developing dementia. It remains to examine whether they can improve the established cardiovascular risk factors aging and dementia (CAIDE) model and how their predictive abilities compare.
METHODS: The CAIDE model was applied to a sub-sample of a large, population-based cohort study (n = 5,360; aged 50-75) and evaluated for the outcomes of all-cause dementia, Alzheimer\'s disease (AD) and vascular dementia (VD) by calculating Akaike\'s information criterion (AIC) and the area under the curve (AUC). The improvement of the CAIDE model by PRS and SCD was further examined using the net reclassification improvement (NRI) method and integrated discrimination improvement (IDI).
RESULTS: During 17 years of follow-up, 410 participants were diagnosed with dementia, including 139 AD and 152 VD diagnoses. Overall, the CAIDE model showed high discriminative ability for all outcomes, reaching AUCs of 0.785, 0.793, and 0.789 for all-cause dementia, AD, and VD, respectively. Adding information on SCD significantly increased NRI for all-cause dementia (4.4%, p = 0.04) and VD (7.7%, p = 0.01). In contrast, prediction models for AD further improved when PRS was added to the model (NRI, 8.4%, p = 0.03). When APOE ε4 carrier status was included (CAIDE Model 2), AUCs increased, but PRS and SCD did not further improve the prediction.
CONCLUSIONS: Unlike PRS, information on SCD can be assessed more efficiently, and thus, the model including SCD can be more easily transferred to the clinical setting. Nevertheless, the two variables seem negligible if APOE ε4 carrier status is available.