Study of the Risk and Preventive Factors for Progress of Mild Cognitive Impairment to Dementia

The updated prevalence and risk factors of dementia in old adults in China: A cross-sectional study

BACKGROUND

The continuously increasing aging population and life expectancy have led to an inconsistent and underestimated dementia prevalence in China. An updated epidemiologic study is urgently needed.

OBJECTIVE

To update the prevalence rate and risk factors of dementia in China.

METHODS

For this national cross-sectional study, 20,438 participants aged ≥65 from 28 communities and 56 villages from 14 centers were recruited using a multistage cluster sampling design between May 2019 and December 2019. Participants were assessed with a series of clinical and neuropsychological measurements. The prevalence rates of dementia, Alzheimer's disease (AD), and vascular dementia (VaD), as well as the risk factors, were calculated using multivariate-adjusted models.

RESULTS

The crude prevalence rates were 9.1% (95% CI, 8.7%-9.5%) for dementia, 6.0% (95% CI, 5.7%-6.3%) for AD, 1.4% (95% CI, 1.2%-1.5%) for VaD, and 1.8% (95% CI, 1.6%-2.0%) for other dementias in a population aged ≥65 years. The overall sex- and age-standardized prevalence was 8.8%. Apart from VaD, the prevalence rates of dementia and AD were higher in females than males (10.3% versus 7.7%, respectively). Moreover, the prevalence rates of dementia and AD increased significantly with age. Being unmarried and having fewer social activities increased the risks of dementia and main subtypes. Risk factors were not exactly the same for participants with AD and VaD.

CONCLUSIONS

The prevalence of dementia is increased and almost comparable with that of developed countries for individuals aged ≥65 years. These findings may serve as new evidence for government interventions in aging.

Cognitive changes in people with diabetes with lower extremity complications compared to people with diabetes without lower extremity complications: a systematic review and meta-analysis

BACKGROUND

Recent evidence suggests that diabetes-related lower-extremity complications (DRLECs) may be associated with cognitive changes in people with diabetes. However, existing literature has produced inconsistent findings, and no systematic reviews have been conducted to investigate whether DRLECs impact the cognition of people with diabetes. This systematic review evaluated existing studies that investigated cognition in people with diabetes with DRLECs and without DRLECs.

METHOD

Seven databases; MEDLINE, PubMed, CINAHL, EMBASE, Cochrane, PsycINFO and Web of Science were searched from inception until 22/8/2022 for studies that compared cognition in people with diabetes with and without DRLECs. Results were independently screened for eligibility and assessed for methodological quality by two authors, with key data extracted. Studies were eligible for meta-analysis if the studies reported similar cases, controls, and outcome measures.

RESULTS

Thirteen studies were included in the review, with eleven of medium methodological quality, one of high quality, and one of low quality. Four studies found significant differences in cognition between those with and without DRLECs, four found significant associations between diabetes-related lower-extremity complications and cognition, and five found no differences or associations. One small meta-analysis of eligible studies found that there was no statistically significant difference in cognition in people without, compared to with, peripheral neuropathy (Mean difference = -0.49; 95%CI: -1.59-0.61; N = 3; n = 215). Leave-one-out sensitivity analyses further confirmed that there was no significant difference in cognition among people with and without peripheral neuropathy (p > 0.05).

CONCLUSION

DRLECs may be related to cognition in people with diabetes, however, existing evidence is unclear due to variability in used methodologies that may challenge concluding the findings. Future high-quality studies investigating cognition among people with and without DRLECs are needed.

Longitudinal Patterns and Predictors of Cognitive Impairment Classification Stability

OBJECTIVE

Classifications such as Cognitive Impairment, No Dementia (CIND) are thought to represent the transitory, pre-clinical phase of dementia. However, increasing research demonstrates that CIND represents a nonlinear, unstable entity that does not always lead to imminent dementia. The present study utilizes a longitudinal repeated measures design to gain a thorough understanding of CIND classification stability patterns and identify predictors of future stability. The objectives were to i) explore patterns of longitudinal stability in cognitive status across multiple assessments and ii) investigate whether select baseline variables could predict 6-year CIND stability patterns.

METHOD

Participants (N = 259) included older adults (aged 65-90 years) from Project MIND, a six-year longitudinal repeated measures design in which participants were classified as either normal cognition (NC) or CIND at each annual assessment. A latent transition analysis approach was adapted in order to identify and characterize transitions in CIND status across annual assessments. Participants were classified as either Stable NC, Stable CIND, Progressers, Reverters, or Fluctuaters. Multinomial logistic regression was employed to test whether baseline predictors were associated with cognitive status stability patterns.

RESULTS

The sample demonstrated high rates of reversion and fluctuation in CIND status across annual assessments. Additionally, premorbid IQ and CIND severity (i.e., single vs. multi-domain impairment) at baseline were significantly associated with select stability outcomes.

CONCLUSIONS

CIND status was unstable for several years following baseline assessment and cognitive reserve may delay or protect against demonstrable cognitive impairment. Further, consideration of cognitive impairment severity at the time of initial classification may improve CIND classifications.

Associations between physical activity, sedentary behaviour and cognitive domain performance of people living with mild cognitive impairment in the community

INTRODUCTION

Physical activity is known to positively influence cognitive performance. For adults with mild cognitive impairment (MCI), the relationship between physical activity levels and cognitive performance is unknown. This cross-sectional study aimed to determine if cognitive performance [as measured by the Montreal Cognitive Assessment (MoCA)] of people living in the community with MCI is associated with their physical activity levels or sedentary behaviour.

METHODS

ActivPAL™ accelerometers were used to objectively measure physical activity and sedentary behaviour for seven full days. Cognitive performance was measured using the MoCA.

CONSUMER AND COMMUNITY INVOLVEMENT

No involvement other than as research participants RESULTS: Eighty-two participants from the Balance on the Brain randomised controlled trial were included. Most participants were retired (88%), with 33 (40%) reporting a fall in the last year. The median MoCA score was 24 (IQR 22-26). Participants achieved a mean of 6296 (±2420) steps per day and were sedentary for 10.6 (±2) hours per day. The only physical activity outcomes that had a fair, positive correlation were moderate- to vigorous-intensity physical activity measures of total stepping time and total number of steps (with a cadence of ≥100 steps/min) with the orientation MoCA domain score (r(82) = 0.36, p ≤ 0.001 and r(82) = 0.37, p ≤ 0.001, respectively). Higher total sedentary time had a weak, positive correlation with better visuospatial/executive performance (r(82) = 0.23, p = 0.041). The orientation outcomes remained significant when analysed in an adjusted logistic regression model.

CONCLUSION

This study found that performance in the MoCA orientation domain had a fair-positive correlation with moderate-intensity physical activity (i.e., stepping time and step count with a cadence of ≥100 steps/min) as measured by a thigh-worn accelerometer for community-dwelling older adults with MCI. When considering the relationship between cognitive domains and sedentary behaviour, consideration may be needed regarding whether cognitive enhancing activities (such as crosswords and other brain games) are being performed, which may confound this relationship. Further investigation is required to confirm these results.

Effects of art therapy for people with mild or major neurocognitive disorders: A systematic review and meta-analysis

OBJECTIVES

The aim of this study was to analyze the efficacy of non-pharmacological, interactive, and emotional art therapy interventions for patients with mild neurocognitive disorder (mild NCD) or major neurocognitive disorder (MNCD).

METHODS

A systematic review and meta-analysis assessed English-language literature published from January 1, 2001, to August 22, 2021, and indexed in CINAHL, EMBASE, MEDLINE, PubMed, Web of Science, and PsycINFO. People with mild NCD or MNCD who received art therapy were classified as the intervention group. Study quality was assessed using the Risk of Bias (RoB) 2 and the Joanna Briggs Institute tool.

RESULTS

Among nine included studies, depression was significantly reduced as compared with control groups (Cohen's d = -0.52 [95 % CI = -0.99-0.05], p < 0.001, I2 = 62.90 %) but not cognitive function or quality of life.

CONCLUSION

People with mild neurocognitive disorder or MNCD are encouraged to engage in art therapy delivered by art therapists collaborating with healthcare providers. The effects of specific types of art therapy should be explored.

PRACTICAL IMPLICATION

Healthcare providers should be encouraged to provide art therapy designed to reduce depression in patients with mild NCD or MNCD.

Depression Is Associated with the Aberration of Resting State Default Mode Network Functional Connectivity in Patients with Amyloid-Positive Mild Cognitive Impairment

Mild cognitive impairment (MCI) is an intermediate stage between normal aging and dementia, and a significant number of individuals with MCI progress to develop dementia. Depression is prevalent in MCI patients and has been found to influence the disease progression of MCI. The default mode network (DMN), a brain network associated with Alzheimer's disease (AD), and its functional connectivity might be a neurological mechanism linking depression and AD. However, the relationship between depression, DMN functional connectivity, and cerebral beta-amyloid (Aβ) pathology remains unclear. This study aimed to investigate DMN functional connectivity differences in Aβ-positive MCI patients with depression compared to those without depression. A total of 126 Aβ-positive MCI patients were included, with 66 having depression and 60 without depression. The results revealed increased functional connectivity in the anterior DMN in the depression group compared to the non-depression group. The functional connectivity of the anterior DMN positively correlated with depression severity but not with Aβ deposition. Our findings suggest that depression influences DMN functional connectivity in Aβ-positive MCI patients, and the depression-associated DMN functional connectivity aberrance might be an important neural mechanism linking depression, Aβ pathology, and disease progression in the trajectory of AD.

The effectiveness of exercise on global cognitive function, balance, depression symptoms, and sleep quality in patients with mild cognitive impairment: A systematic review and meta-analysis

This review aimed to examine the effectiveness of exercise on global cognitive function, balance, depression symptoms, and sleep quality in patients with mild cognitive impairment. And systematically retrieved five electronic databases, including the Cochrane library, PubMed, Embase, Web of Science, and PsycINFO, from inception to May 2022. Of 1102 studies, twenty-one studies were included in this meta-analysis. The polled results revealed that exercise could significantly improve global cognitive function (SMD = 0.64, 95%CI: 0.36 to 0.91, Z = 4.56, P < 0.00001), balance (SMD = 0.62, 95%CI: 0.30 to 0.95, Z = 4.56, P = 0.0001) and depression symptoms (SMD = -0.37, 95%CI: -0.64 to -0.10, Z = 2.70, P = 0.007). The exercise was a promising intervention with the potential to be applied in people with mild cognitive impairment.

Cognition and cardiovascular comorbidities among older adults in primary care in West India

Objectives

Cardiovascular risk factors (e.g., diabetes and hypertension) are comorbidities associated with cognitive impairment. The present study was planned to study the relationship between cardiovascular risk factors and cognitive impairment using General Practitioner assessment of Cognition (GPCOG) scale, which is easy to use scale in the primary care.

Materials and Methods

A total of 350 older adults (mean age=66.71 ± 6.53 years; M:F = 220:130) among 3000 who reported to the primary care center in West India were screened. Cardiovascular risk factors were assessed based on written medical records. GPCOG was used for cognitive screening of those over the age of 60 with subjective memory complaints.

Results

Frequency of cardiovascular (CV) risk factors in those with cognitive impairment was 46.2% (n = 162/350) and 29% (101/350) in those without cognitive impairment. A Chi-square test of proportion showed values to be statistically significantly different (Chi-square value = 22.04; P =< 0.001; 95% confidence interval [CI] = 10.0463-24.1076%). Odds ratio was found to be 1.6 (95% CI =2-2.1; P =< 0.05).

Conclusion

A higher CV risk factors were observed among those with cognitive impairment compared to those cognitively normal older adults in the primary care.

The efficacy and mechanism of berberine in improving aging-related cognitive dysfunction: A study based on network pharmacology

Objective

To analyze the effects and mechanisms of berberine in the treatment of aging-related cognitive dysfunction based on network pharmacology methods, molecular docking techniques, and animal experiments.

Methods

A mouse model of cognitive dysfunction was constructed by subcutaneous injection of D-galactose (D-gal) for 10 weeks, and the neuroprotective effects of berberine on aging-related cognitive dysfunction mice were evaluated by the Morris water maze (MWM) and immunofluorescence staining. The targets of berberine were obtained by SwissTargetPrediction, GeneCards, and PharmMapper. Putative targets of cognitive dysfunction were obtained by GeneCards, TTD, and DrugBank database. The STRING database and Cytoscape software were applied for protein-protein interaction (PPI) analysis and further screening of core targets. The DAVID database was used for Kyoto Encyclopedia of Genes and Genomes (KEGG) and gene ontology (GO) enrichment analysis to clarify the biological processes and pathways involved in the intersection targets, and AutoDockTools was adopted for molecular docking verification of core targets. Finally, the core genes were validated using real-time quantitative PCR.

Results

The MWM results showed that treatment with berberine significantly improved spatial learning and memory in mice with cognitive decline induced by D-gal. Immunofluorescence staining indicated that berberine modified the levels of aging-related markers in the brain. A total of 386 berberine putative targets associated with cognitive dysfunction were identified based on the public database. The core targets of berberine for improving cognitive function, include Mapk1, Src, Ctnnb1, Akt1, Pik3ca, Tp53, Jun, and Hsp90aa1. GO enrichment and KEGG pathway enrichment analyses indicated that the mechanism of berberine in the treatment of aging-related cognitive dysfunction is attributed to pathways such as PI3K-AKT and MAPK pathways. In vivo experiments further confirmed that Akt1, Ctnnb1, Tp53, and Jun were involved in the neuroprotective actions of berberine.

Conclusion

This study reveals the multi-target and multi-pathway effects of berberine on regulating aging-related cognitive dysfunction, which provides preclinical evidence and may promote new drug development in mitigating cognitive dysfunction.

Speed of Processing (SoP) Training Plus α-tACS in People With Mild Cognitive Impairment: A Double Blind, Parallel, Placebo Controlled Trial Study Protocol

Several cognitive training programs, alone or in combination with non-invasive brain stimulation have been tested in order to ameliorate age-related cognitive impairments, such as the ones found in Mild Cognitive Impairment (MCI). However, the effects of Cognitive Training (CT)—combined or not—with several forms of non-invasive brain stimulation have been modest at most. We aim to assess if Speed of Processing (SoP) training combined with alpha transcranial alternating current stimulation (α-tACS) is able to increase speed of processing as assessed by the Useful Field of View (UFOV), when comparing to SoP training or active α-tACS alone. Moreover, we want to assess if those changes in speed of processing transfer to other cognitive domains, such as memory, language and executive functioning by using the NIH EXAMINER. We also want to test the mechanisms underlying these interventions, namely brain connectivity and coherence as assessed by electroencephalography (EEG). To that purpose, our proposal is to enroll 327 elders diagnosed with MCI in a double-blinded, parallel randomized clinical trial assessing the effects of combining SoP with alpha endogenous tACS (either active or sham) in people with MCI. Participants will perform an intervention that will last for 15 sessions. For the first 3 weeks, participants will receive nine sessions of the intervention, and then will receive two sessions per week (i.e., booster) for the following 3 weeks. They will then be assessed at 1, 3, and 6 months after the intervention has ended. This will allow us to detect the immediate, and long-term effects of the interventions, as well as to probe the mechanisms underlying its effects.

Clinical Trial Registration:Clinicaltrials.gov, Identifier: NCT05198726.

Association between tooth loss rate and risk of mild cognitive impairment in older adults: a population-based longitudinal study

Mild cognitive impairment (MCI) is a symptomatic predementia phase of the trajectory of cognitive decline, and its prevalence increases with age. Although the relationship between oral health and MCI have been explored previously, it is uncertain whether individuals with different tooth loss rates have altered MCI risks. We hereby conducted a longitudinal study by using data from the Chinese Longitudinal Healthy Longevity Survey to investigate the association. Tooth loss rate was defined as the difference of teeth between two interview waves divided by years of interval; participants were then grouped into four categories: stable, no tooth loss; mild, 0-1 tooth loss; middle, 1-2 tooth loss; and severe, more than 2 tooth loss per year. Cognitive function was assessed by the Chinese version of Mini-Mental State Examination. We used the generalized estimating equation model to estimate the odds ratio (OR) and the 95% confidence intervals (CIs) and applied the restricted cubic spline function to explore the dose-response association. Among 11,862 participants, 3,966 developed MCI in a median follow-up time of 5.93 years. Higher tooth loss rate was associated with an increased risk of MCI in elderly subjects. Compared with subjects with stable tooth, the corresponding ORs (95% CIs) were 0.94 (0.85-1.03), 1.16 (1.04-1.29) and 1.28 (1.17-1.40) for subjects with the mild, middle and severe rate of tooth loss. A nonlinear dose-response relationship was detected (P_{non-linearity} = 0.0165). Similar results were observed in the subgroup analyses stratified by sex, age at baseline, and number of teeth at baseline. The positive association was only observed among denture nonwearers (OR _{middle vs stable}: 1.19; 1.06-1.35; OR _{severe vs stable}: 1.35; 1.22-1.50), but not among denture wearers. In conclusion, among elderly population in China, higher rate of tooth loss may be associated with an increased risk of MCI, while denture wearers may be less likely to develop MCI.