Association of Dual Decline in Cognition and Gait Speed With Risk of Dementia in Older Adults

Association between depressive symptoms and cognitive function in the older population, and the mediating role of neurofilament light chain: Evidence from NHANES 2013-2014

OBJECTIVE

This study aimed to investigate the potential mediating role of the neurofilament light chain (NfL) level between depressive symptoms and cognitive function in older population.

METHODS

A total of 495 adults (age ≥60 years) from the National Health and Nutrition Examination Survey (NHANES) participated in this study. Cognitive function was assessed using a combination of the Animal Fluency Test (AFT), the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) and the Digit Symbol Substitution Test (DSST). Word List Learning Test. Patient Health Questionnaire-9 (PHQ-9) was used to assess depressive symptoms. Data on serum NfL(sNfL) were collected. Multiple linear regressions and mediation analysis were utilized to examine the associations.

RESULTS

After adjusting for potential confounding factors, the proportions mediated by the sNfL level between depressive symptoms and cognitive function was 19.65 %. The indirect effect mediated by the sNfL level between depressive symptoms and cognitive function was significant (β[95 % CI]:-0.0089 [-0.0191, -0.0017],p = 0.040), while the direct effect in the absence of sNfL was non-significant (β[95 % CI]: -0.0365 [-0.0739 0.0008],p = 0.055).

LIMITATIONS

This is an explorative cross-sectional study with its limits in generalizability and ability to establish definitive causal associations. The results should be interpreted with caution due to the constraints imposed by the characteristics of the population with a relatively low overall level of depressive symptoms.

CONCLUSION

The sNfL level, depressive symptoms, and cognitive decline are interconnected, and the sNfL level could mediate the relationship between depressive symptoms and cognitive decline among older adults.

Shared plasma metabolomic profiles of cognitive and mobility decline predict future dementia

Experiencing decline in both cognition and mobility is associated with a substantially higher dementia risk than cognitive decline only. Metabolites associated with both cognitive and mobility declines may be early predictors of dementia and reveal specific pathways to dementia. We analyzed data from 2450 participants initially free of dementia who had 613 metabolites measured in plasma in 1998-1999 (mean age = 75.2 ± 2.9 years old, 37.8% Black, 50% women) from the Health, Aging and Body Composition study. Dementia diagnosis was determined by race-specific decline in 3MS scores, medication use, and hospital records through 2014. Cognition and mobility were repeatedly measured using 3MS and a 20-m walking test up to 10 years, respectively. We examined metabolite associations with changes in 3MS (n = 2046) and gait speed (n = 2019) using multivariable linear regression adjusted for age, sex, race, and baseline performance and examined metabolite associations with dementia risk using Cox regression. During a mean follow-up of 9.3 years, 534 (21.8%) participants developed dementia. On average, 3MS declined 0.47/year and gait declined 0.04 m/sec/year. After covariate adjustment, 75 metabolites were associated with cognitive decline, and 111 metabolites were associated with gait decline (FDR-adjusted p < 0.05). Twenty-six metabolites were associated with both cognitive and gait declines. Eighteen of 26 metabolites were associated with dementia risk (p < 0.05), notably amino acids, glycerophospholipids (lysoPCs, PCs, PEs), and sphingolipids. Results remained similar after adjusting for cardiovascular disease or apolipoprotein E ɛ4 carrier status. During aging, metabolomic profiles of cognitive decline and mobility decline show distinct and shared signatures. Shared metabolomic profiles suggest that inflammation and deficits in mitochondria and the urea cycle in addition to the central nervous system may play key roles in both cognitive and mobility declines and predict dementia. Future studies are warranted to investigate longitudinal metabolite changes and metabolomic markers with dementia pathologies.

Cognitive function in different motor subtypes of Parkinson's disease: A systematic review protocol

Background and Aims

As the fastest-growing neurological disorder globally, a better understanding of Parkinson's disease (PD) is needed to improve patient outcomes and reduce the increasing economic and healthcare burden associated with the disease. Whilst classified as a movement disorder, this disease is highly heterogeneous, encompassing a broad range of both motor and non-motor symptoms (NMS). Cognitive impairment, presenting as either mild cognitive impairment or PD-dementia, is one of the most prevalent and disabling NMS. To better understand heterogeneity in PD, researchers have sought to identify subtypes of individuals who share similar symptom profiles. To date, this research has predominantly focused on motor subtyping, with many studies comparing these motor subtypes on non-motor outcomes, such as cognitive impairment. However, despite evidence of a motor-cognitive relationship in healthy aging, findings regarding the presence of a motor-cognitive relationship in PD are inconsistent. In our proposed systematic review, we will investigate motor subtyping studies that have evaluated the relationship between motor and cognitive function in PD. We aim to examine what is currently known about the relationship between motor and cognitive impairment in PD and evaluate the state of the field with respect to the subtyping methods and quality of cognitive assessment tools used.

Methods

Systematic literature searches will be conducted in PubMed, PsycINFO, CINAHL, Scopus, and Web of Science.

Results

Results will be synthesized using meta-analysis and, where meta-analysis is not feasible, narrative synthesis.

Conclusion

Despite the preponderance of motor subtyping research in PD, our study will be the first to systematically review evidence regarding the association between motor subtypes and cognitive impairment. Understanding the nature of the motor-cognitive relationship in PD may lead to important insights regarding shared underlying disease pathology, which would have significant implications for early diagnosis, prognosis, and treatment of cognitive impairment in PD.

[Alusti test as a premonitory variable of adverse health events in a nursing home. Two-years follow-up]

INTRODUCTION

Functional capacity is a good indicator of health, quality of life, and a good predictor of morbimortality. It is a priority to functionally assess the geriatric population through objective, precise, and simple instruments. The Alusti Test in its two versions, complete (TA) and abbreviated (TAA), is a scale that meets these criteria.

OBJECTIVE

To determine the usefulness of the Alusti Test as a predictor of adverse health events: falls, hospitalizations, cognitive deterioration, and mortality in the elderly institutionalized population, with a two-year follow-up.

MATERIAL AND METHODS

This observational study's sample included 176 persons admitted to a nursing home for 32months, with a mean age of 85.5years. The TA was performed on 138 and the TAA on 38.

RESULTS

The ratio of falls is much higher in residents with mild dependence than in those with total dependence (P<.001). Hospitalizations increase as the results of the Alusti Test are more favorable. The risk of hospitalization in dependent patients is 50% lower (P<.001) than in those with preserved mobility. Cognitive impairment is similar in all the populations with some mild-moderate level of functional dependence and decreases in the population with preserved mobility. Categorization as total and mild/severe dependence is related to a 3-4times higher mortality at six months follow-up.

CONCLUSIONS

A higher mild-moderate level of dependence on the AT correlates with a lower risk of falls, a lower rate of hospitalization, and a higher risk of mortality at six months.

Can motor decline be a modifiable marker of clinical progression in subjective cognitive decline? A national prospective cohort study

OBJECTIVES

Subjective cognitive decline represents a critical stage for preventing mild cognitive impairment and dementia, but the links between clinical progression in the subjective cognitive decline stage and various motor functions remain inconclusive. This cohort study aimed to elucidate the independent and joint associations between the clinical progression of subjective cognitive decline and motor functions.

METHODS

We enrolled 4880 community-dwelling elderly participants from a national cohort and used Cox proportional hazard regression model and restricted cubic spline models to explore the longitudinal associations between motor functions (gait, strength, balance, and endurance) and the clinical progression of subjective cognitive decline.

RESULTS

During 5-years follow-up, 1239 participants experienced clinical progression. After adjusting for demographics, vascular burden, body components, and polypharmacy, gait speed [hazard ratios (HRs)= 0.96, 95% confidence interval (CI) 0.94-0.99], chair stand test (HRs=1.02, 95%CI 1.01-1.03), and endurance limitation in jogging 1 kilometer (HRs=1.18, 95%CI 1.04-1.34) were significantly associated with clinical progression. Among all participants, individuals characterized by poor upper- and lower-body strength, as well as those with slow pace and reduced endurance, faced the highest risk of cognitive impairment.

CONCLUSIONS

This study emphasizes the potential of gait speed, muscle strength, and endurance as non-cognitive indicators of clinical progression in subjective cognitive decline. Understanding their combined effectiveness may reveal primary physiological mechanisms contributing to the dual decline of motor and cognition.

The effects of 6-week home-based static stretching, dynamic stretching, or eccentric exercise interventions on muscle-tendon properties and functional performance in older women

Background

Joint inflexibility is acknowledged as a significant contributor to functional limitations in the older adult, with lengthening-type exercises identified as a potential remedial approach. Nevertheless, the responses to eccentric exercise in female older adults have not been extensively studied especially in home-based environment. Here, we aimed to assess the effectiveness of home-based static stretching (ST), dynamic closed-chain stretching (DCS), or eccentric exercise (ECC) interventions on flexibility, musculotendinous architecture, and functional ability in healthy older women.

Methods

We randomly assigned 51 healthy older women (age 65.9 ± 3.4 years) to one of three interventional exercise groups: DCS (N = 17), ECC (N = 17), or ST (N = 17). The training was performed 3 times a week for 6 weeks. The participants' musculotendinous stiffness, fascicle length, eccentric strength, and functional capacities were measured before the intervention, after 6 weeks of exercise, and at a 1-month follow-up.

Results

The results showed that all three interventions improved hamstring flexibility and passive ankle dorsiflexion (p < 0.001), with increased biceps femoris and medial gastrocnemius fascicle length (p < 0.01). However, there was no significant change in musculotendinous stiffness. The ECC intervention produced a greater improvement in knee flexor and calf eccentric peak torque (p < 0.05), and gait speed (p = 0.024) than the other two interventions. The changes in flexibility and knee flexor strength remained for up to 4 weeks after detraining.

Conclusion

In conclusion, the present study suggests that home-based ECC may be more beneficial in enhancing physical capacities in older women compared with either DCS or SS interventions.

Tutorial: Lessons Learned for Behavior Analysts from Data Scientists

Big data is a computing term used to refer to large and complex data sets, typically consisting of terabytes or more of diverse data that is produced rapidly. The analysis of such complex data sets requires advanced analysis techniques with the capacity to identify patterns and abstract meanings from the vast data. The field of data science combines computer science with mathematics/statistics and leverages artificial intelligence, in particular machine learning, to analyze big data. This field holds great promise for behavior analysis, where both clinical and research studies produce large volumes of diverse data at a rapid pace (i.e., big data). This article presents basic lessons for the behavior analytic researchers and clinicians regarding integration of data science into the field of behavior analysis. We provide guidance on how to collect, protect, and process the data, while highlighting the importance of collaborating with data scientists to select a proper machine learning model that aligns with the project goals and develop models with input from human experts. We hope this serves as a guide to support the behavior analysts interested in the field of data science to advance their practice or research, and helps them avoid some common pitfalls.

Dual decline in subjective gait speed and domain-specific cognition is associated with higher risk of incident dementia in older Japanese adults: A 15-year age-specific cohort study

OBJECTIVES

Dual decline in gait speed and cognition has been found to have higher dementia risk than no decline or pure decline. However, evidence from the Asian population is lacking. Therefore, we aimed to investigate the association of dual decline from age 65 to 70 years with late-life dementia in older Japanese adults with different personal characteristics.

METHODS

Data were collected from an age-specific cohort study conducted in 482 Japanese 65-year-old adults. We investigated participant demographics, medical histories, lifestyles, subjective gait speed, and cognition at both 64/65 and 70/71 years old, and confirmed dementia until age of 85 years. Cox proportion hazard models were used to estimate the risk of dementia, with adjustments for covariates, and death was treated as a competing risk.

RESULTS

After a mean follow-up period of 12.5-years, 111 participants developed dementia. Older adults with dual decline are more likely to have hyperlipidemia, diabetes, and smoking habits. And we found that dual decline in gait speed and domain-specific cognition was associated with a higher risk of dementia compared with no decline in most cognitive tests, with the highest risk observed for gait speed combined with memory (sub-distribution hazard ratio:3.89, 95 %, confidence intervals: [1.68-9.01]). However, significant differences only existed in men after stratification by sex.

CONCLUSIONS

A dual decline in subjective gait speed and cognition may serve as a robust predictor of dementia over a decade prior to its onset, particularly in men. These findings highlighted the importance of screening for dual decline at an early age.

White matter microstructure alterations in type 2 diabetes mellitus and its correlation with cerebral small vessel disease and cognitive performance

Microstructural abnormalities of white matter fiber tracts are considered as one of the etiology of diabetes-induced neurological disorders. We explored the cerebral white matter microstructure alteration accurately, and to analyze its correlation between cerebral small vessel disease (CSVD) burden and cognitive performance in type 2 diabetes mellitus (T2DM). The clinical-laboratory data, cognitive scores [including mini-mental state examination (MMSE), Montreal cognitive assessment (MoCA), California verbal learning test (CVLT), and symbol digit modalities test (SDMT)], CSVD burden scores of the T2DM group (n = 34) and healthy control (HC) group (n = 21) were collected prospectively. Automatic fiber quantification (AFQ) was applied to generate bundle profiles along primary white matter fiber tracts. Diffusion tensor images (DTI) metrics and 100 nodes of white matter fiber tracts between groups were compared. Multiple regression analysis was used to analyze the relationship between DTI metrics and cognitive scores and CSVD burden scores. For fiber-wise and node-wise, DTI metrics in some commissural and association fibers were increased in T2DM. Some white matter fiber tracts DTI metrics were independent predictors of cognitive scores and CSVD burden scores. White matter fiber tracts damage in patients with T2DM may be characterized in specific location, especially commissural and association fibers. Aberrational specific white matter fiber tracts are associated with visuospatial function and CSVD burden.

Doll therapy for improving behavior, psychology and cognition among older nursing home residents with dementia: A systematic review and meta-analysis

OBJECTIVE

To explore the effectiveness of doll therapy (DT) on behavior, psychology and cognition among older nursing home residents with dementia.

METHODS

A systematic review and meta-analysis was conducted. Subgroup analyses were performed to determine whether the intervention characteristics influenced effect sizes.

RESULTS

Ten studies met the inclusion criteria and were selected for qualitative and quantitative synthesis. The overall methodological quality was relatively high. DT significantly improved all behaviors [SMD=-0.42, P=0.01], including agitation [SMD=-0.94, P<0.001], apathy, irritability and wandering, and psychological states (i.e., pleasure, anxiety and depression). However, there was no significant difference in the improvement of cognition. Subgroup analyses revealed that the DT process employing empathy dolls and coordinating with caregivers was more beneficial for improving all behaviors (P=0.01; P=0.02).

CONCLUSION

DT significantly reduced behavioral and psychological disturbances among older nursing home residents with dementia. Specifically, administering empathy dolls and coordinating with caregivers may be the most appropriate and effective option.

Using dual-task gait to recognize Alzheimer's disease and mild cognitive impairment: a cross-sectional study

Background

Gait is a potential diagnostic tool for detecting mild cognitive impairment (MCI) and Alzheimer's disease (AD). Nevertheless, little attention has been paid to arm movements during walking, and there is currently no consensus on gait asymmetry. Therefore, in this study, we aimed to determine whether arm motion and gait asymmetry could be utilized for identifying MCI and AD.

Methods

In total, 102 middle-aged and elderly individuals were included in the final analysis and were assigned to the following three groups: AD (n = 27), MCI (n = 35), and a normal control group (n = 40). Gait and cognitive assessments were conducted for all participants. Gait detection included a single-task gait with free-speed walking and a dual-task gait with adding a cognitive task of successive minus seven to walking. Original gait parameters were collected using a wearable device featuring the MATRIX system 2.0. Gait parameters were shortened to several main gait domains through factor analysis using principal component extraction with varimax rotation. Subsequently, the extracted gait domains were used to differentiate the three groups, and the area under the receiver operating characteristic curve was calculated.

Results

Factor analysis of single-task gait identified five independent gait domains: rhythm symmetry, rhythm, pace asymmetry, arm motion, and variability. Factor analysis of the dual-task gait identified four gait domains: rhythm, variability, symmetry, and arm motion. During single-task walking, pace asymmetry was negatively correlated with MoCA scores and could distinguish between the AD group and the other two groups. Arm motion was not associated with MoCA scores, and did not exhibit adequate discrimination in either task.

Conclusion

Currently, there is no reliable evidence suggesting that arm motion can be used to recognize AD or MCI. Gait asymmetry can serve as a potential gait marker for the auxiliary diagnosis of AD but not for MCI.

Validation of newly derived polygenic risk scores for dementia in a prospective study of older individuals

INTRODUCTION

Recent genome-wide association studies identified new dementia-associated variants. We assessed the performance of updated polygenic risk scores (PRSs) using these variants in an independent cohort.

METHODS

We used Cox models and area under the curve (AUC) to validate new PRSs (PRS-83SNP, PRS-SBayesR, and PRS-CS) compared with an older PRS-23SNP in 12,031 initially-healthy participants ≥70 years of age. Dementia was rigorously adjudicated according to Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) criteria.

RESULTS

PRS-83SNP, PRS-SBayesR, and PRS-CS were associated with incident dementia, with fully adjusted (including apolipoprotein E [APOE] ε4) hazard ratios per standard deviation (SD) of 1.35 (1.23-1.47), 1.37 (1.25-1.50), and 1.42 (1.30-1.56), respectively. The AUC of a model containing conventional/non-genetic factors and APOE was 74.7%. This was improved to 75.7% (p = 0.007), 76% (p = 0.004), and 76.1% (p = 0.003) with addition of PRS-83SNP, PRS-SBayesR, and PRS-CS, respectively. The PRS-23SNP did not improve AUC (74.7%, p = 0.95).

CONCLUSION

New PRSs for dementia significantly improve risk-prediction performance, but still account for less risk than APOE genotype overall.

Gender and age influence the association between gait speed and mild cognitive impairment in community-dwelling Japanese older adults: from the Japan Prospective Studies Collaboration for Ageing and Dementia (JPSC-AD)

BACKGROUND

Studies have shown that decreased gait speed is associated with impaired cognitive function. However, whether this association is equivalent across ages or genders in the older population remains unclear. Thus, we examined the association between mild cognitive impairment (MCI) and gait speed emphasising the influence of age and gender.

METHODS

Overall, 8233 Japanese participants aged ≥65 years were enrolled in this cross-sectional study between 2016 and 2018. After stratification by gender and age group, the participants' gait speeds were divided into quintiles, and the difference in MCI prevalence at each gait speed quintile was calculated. Logistic regression analyses were performed to assess the odds of MCI for each quintile and to assess the influence of age and gender.

RESULTS

Males had a consistently higher prevalence of MCI than females. The odds of MCI were increased as gait speed decreased. Logistic regression analyses revealed that in the multivariable-adjusted model 2, the odds ratios (95% confidence interval; CI) for MCI were 2.02 (1.47-2.76) for females and 1.75 (1.29-2.38) for males in the slowest gait speed quintiles compared to the fastest quintile. In the stratified analyses, only males showed an age-dependent increase in the associations between gait speed and MCI, while females exhibited comparable associations across age groups.

CONCLUSIONS

Reduced gait speed was associated with increased odds of MCI, and this association may vary according to gender and age. Therefore, gait speed could serve as a valuable screening tool for MCI, with gender- and age-dependent clinical implications.

Prediction of conversion to dementia disorders based on timed up and go dual-task test verbal and motor outcomes: a five-year prospective memory-clinic-based study

BACKGROUND

While assessment tools can increase the detection of cognitive impairment, there is currently insufficient evidence regarding clinical outcomes based on screening for cognitive impairment in older adults.

METHODS

The study purpose was to investigate whether Timed Up and Go dual-task test (TUGdt) results, based on TUG combined with two different verbal tasks (name different animals, TUGdt-NA, and recite months in reverse order, TUGdt-MB), predicted dementia incidence over a period of five years among patients (N = 186, mean = 70.7 years; 45.7% female) diagnosed with Subjective Cognitive Impairment (SCI) and Mild Cognitive Impairment (MCI) following assessment at two memory clinics. Associations between TUG parameters and dementia incidence were examined in Cox regression models.

RESULTS

During follow-up time (median (range) 3.7 (0.1-6.1) years) 98 participants converted to dementia. Novel findings indicated that the TUGdt parameter words/time, after adjustment for age, gender, and education, can be used for the prediction of conversion to dementia in participants with SCI or MCI over a period of five years. Among the TUG-related parameters investigated, words/time showed the best predictive capacity, while time scores of TUG and TUGdt as well as TUGdt cost did not produce significant predictive results. Results further showed that the step parameter step length during TUGdt predicts conversion to dementia before adjustment for age, gender, and education. Optimal TUGdt cutoffs for predicting dementia at 2- and 4-year follow-up based on words/time were calculated. The sensitivity of the TUGdt cutoffs was high at 2-year follow-up: TUGdt-NA words/time, 0.79; TUGdt-MB words/time, 0.71; reducing respectively to 0.64 and 0.65 at 4-year follow-up.

CONCLUSIONS

TUGdt words/time parameters have potential as cost-efficient tools for conversion-to-dementia risk assessment, useful for research and clinical purposes. These parameters may be able to bridge the gap of insufficient evidence for such clinical outcomes.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT05893524: https://www.

CLINICALTRIALS

gov/study/NCT05893524?id=NCT05893524&rank=1 .

Spatiotemporal Gait Parameters in Adults With Premanifest and Manifest Huntington's Disease: A Systematic Review

OBJECTIVE

To systematically review and critically evaluate literature on spatiotemporal gait deviations in individuals with premanifest and manifest Huntington's Disease (HD) in comparison with healthy cohorts.

METHODS

We conducted a systematic review, guided by the Joanna Briggs Institute's Manual for Evidence Synthesis and pre-registered with the International Prospective Register of Systematic Reviews. Eight electronic databases were searched. Studies comparing spatiotemporal footstep parameters in adults with premanifest and manifest HD to healthy controls were screened, included and critically appraised by independent reviewers. Data on spatiotemporal gait changes and variability were extracted and synthesised. Meta-analysis was performed on gait speed, cadence, stride length and stride length variability measures.

RESULTS

We screened 2,721 studies, identified 1,245 studies and included 25 studies (total 1,088 participants). Sample sizes ranged from 14 to 96. Overall, the quality of the studies was assessed as good, but reporting of confounding factors was often unclear. Meta-analysis found spatiotemporal gait deviations in participants with HD compared to healthy controls, commencing in the premanifest stage. Individuals with premanifest HD walk significantly slower (-0.17 m/s; 95% confidence interval [CI] [-0.22, -0.13]), with reduced cadence (-6.63 steps/min; 95% CI [-10.62, -2.65]) and stride length (-0.09 m; 95% CI [-0.13, -0.05]). Stride length variability was also increased in premanifest cohorts by 2.18% (95% CI [0.69, 3.68]), with these changes exacerbated in participants with manifest disease.

CONCLUSION

Findings suggest individuals with premanifest and manifest HD display significant spatiotemporal footstep deviations. Clinicians could monitor individuals in the premanifest stage of disease for gait changes to identify the onset of Huntington's symptoms.

Plasma metabolomic signatures of dual decline in memory and gait in older adults

Older adults experiencing dual decline in memory and gait have greater dementia risk than those with memory or gait decline only, but mechanisms are unknown. Dual decline may indicate specific pathophysiological pathways to dementia which can be reflected by circulating metabolites. We compared longitudinal changes in plasma metabolite biomarkers of older adults with and without dual decline in the Baltimore Longitudinal Study of Aging (BLSA). Participants were grouped into 4 phenotypes based on annual rates of decline in verbal memory and gait speed: no decline in memory or gait, memory decline only, gait decline only, and dual decline. Repeated measures of plasma metabolomics were measured by biocrates p500 kit during the same time of memory and gait assessments. In BLSA, 18 metabolites differed across groups (q-value < 0.05). Metabolites differentially abundant were enriched for lysophosphatidylcholines (lysoPC C18:0,C16:0,C17:0,C18:1,C18:2), ceramides (d18:2/24:0,d16:1/24:0,d16:1/23:0), and amino acids (glycine) classes. Compared to no decline, the dual decline group showed greater declines in lysoPC C18:0, homoarginine synthesis, and the metabolite module containing mostly triglycerides, and showed a greater increase in indoleamine 2,3-dioxygenase (IDO) activity. Metabolites distinguishing dual decline and no decline groups were implicated in metabolic pathways of the aminoacyl-tRNA biosynthesis, valine, leucine and isoleucine biosynthesis, histidine metabolism, and sphingolipid metabolism. Older adults with dual decline exhibit the most extensive alterations in metabolic profiling of lysoPCs, ceramides, IDO activity, and homoarginine synthesis. Alterations in these metabolites may indicate mitochondrial dysfunction, compromised immunity, and elevated burden of cardiovascular and kidney pathology.

Functional topography of the neocortex predicts covariation in complex cognitive and basic motor abilities

Although higher-order cognitive and lower-order sensorimotor abilities are generally regarded as distinct and studied separately, there is evidence that they not only covary but also that this covariation increases across the lifespan. This pattern has been leveraged in clinical settings where a simple assessment of sensory or motor ability (e.g. hearing, gait speed) can forecast age-related cognitive decline and risk for dementia. However, the brain mechanisms underlying cognitive, sensory, and motor covariation are largely unknown. Here, we examined whether such covariation in midlife reflects variability in common versus distinct neocortical networks using individualized maps of functional topography derived from BOLD fMRI data collected in 769 45-year-old members of a population-representative cohort. Analyses revealed that variability in basic motor but not hearing ability reflected individual differences in the functional topography of neocortical networks typically supporting cognitive ability. These patterns suggest that covariation in motor and cognitive abilities in midlife reflects convergence of function in higher-order neocortical networks and that gait speed may not be simply a measure of physical function but rather an integrative index of nervous system health.

Dual cognitive and mobility impairments and future dementia - Setting a research agenda

Dual cognitive and mobility impairments are associated with an increased risk of dementia. Recent studies examining temporal trajectories of mobility and cognitive function in aging found that dual decline is associated with higher dementia risk than memory decline or gait decline only. Although initial data show that individuals with dual decline or impairment have excessive cardiovascular and metabolic risk factors, the causes of dual decline or what underlies dual decline with a high risk of dementia remain largely unknown. In December 2021, the National Institute on Aging Intramural and Extramural Programs jointly organized a workshop on Biology Underlying Moving and Thinking to explore the hypothesis that older persons with dual decline may develop dementia through a specific pathophysiological pathway. The working group discussed assessment methods for dual decline and possible mechanisms connecting dual decline with dementia risk and pinpointed the most critical questions to be addressed from a translational perspective.

Age-Related Trajectories of General Fluid Cognition and Functional Decline in the Health and Retirement Study: A Bivariate Latent Growth Analysis

There have been few studies on associations between age-related declines in fluid cognition and functional ability in population-representative samples of middle-aged and older adults. We used a two-stage process (longitudinal factor analysis followed by structural growth modeling) to estimate bivariate trajectories of age-related changes in general fluid cognition (numeracy, category fluency, executive functioning, and recall memory) and functional limitation (difficulties in daily activities, instrumental activities, and mobility). Data came from the Health and Retirement Study (Waves 2010-2016; N = 14,489; ages 50-85 years). Cognitive ability declined on average by -0.05 SD between ages 50-70 years, then -0.28 SD from 70-85 years. Functional limitation increased on average by +0.22 SD between ages 50-70 years, then +0.68 SD from 70-85 years. Significant individual variation in cognitive and functional changes was observed across age windows. Importantly, cognitive decline in middle age (pre-age 70 years) was strongly correlated with increasing functional limitation (r = -.49, p < .001). After middle age, cognition declined independently of change in functional limitation. To our knowledge, this is the first study to estimate age-related changes in fluid cognitive measures introduced in the HRS between 2010-2016.

Predictors of cognitive and physical decline: Results from the Health Aging and Body Composition Study

Background

Risk factors for cognitive decline and physical decline have been studied independently, however older adults might experience decline in both areas i.e., dual decline. Risk factors associated with dual decline are largely unknown and have significant implications on health outcomes. The aim of this study is to explore risk factors associated with dual decline.

Methods

Using data from the Health, Aging and Body Composition (Health ABC) study, a longitudinal prospective cohort study, we examined trajectories of decline based on repeated measures of the Modified Mini-Mental State Exam (3MSE) and the Short Physical Performance Battery (SPPB) across 6 years (n=1,552). We calculated four mutually exclusive trajectories of decline and explored predictors of decline: cognitive decline (n = 306) = lowest quartile of slope on the 3MSE or 1.5 SD below mean at baseline, physical decline (n = 231) = lowest quartile of slope on the SPPB or 1.5 SD below mean at baseline, dual decline (n = 110) = lowest quartile in both measures or 1.5 SD below mean in both measures at baseline. Individuals who did not meet criteria for one of the decline groups were classified as the reference group. (n= 905).

Results

Multinomial logistic regression tested the association of 17 baseline risk factors with decline. Odds of dual decline where significantly higher for individuals at baseline with depressive symptoms (CES-D >16) (Odds Ratio (OR)=2.49, 95% Confidence Interval (CI): 1.05-6.29), ApoE-ε4 carrier (OR= 2.09, 95% CI: 1.06-1.95), or if individuals had lost 5+lbs in past year (OR=1.79, 95% CI: 1.13-2.84). Odds were significantly lower for individuals with a higher score on the Digit Symbol Substitution Test per standard deviation (OR per SD: 0.47, 95% CI 0.36-0.62) and faster 400-meter gait (OR per SD= 0.49, 95% CI: 0.37-0.64).

Conclusion

Among predictors, depressive symptoms at baseline significantly increased the odds of developing dual decline but was not associated with decline in the exclusively cognitive or physical decline groups. APOE-ε4 status increased the odds for cognitive decline and dual decline but not physical decline. More research on dual decline is needed because this group represents a high risk, vulnerable subset of older adults.

Functional Topography of the Neocortex Predicts Covariation in Complex Cognitive and Basic Motor Abilities

Although higher-order cognitive and lower-order sensorimotor abilities are generally regarded as distinct and studied separately, there is evidence that they not only covary but also that this covariation increases across the lifespan. This pattern has been leveraged in clinical settings where a simple assessment of sensory or motor ability (e.g., hearing, gait speed) can forecast age-related cognitive decline and risk for dementia. However, the brain mechanisms underlying cognitive, sensory, and motor covariation are largely unknown. Here, we examined whether such covariation in midlife reflects variability in common versus distinct neocortical networks using individualized maps of functional topography derived from BOLD fMRI data collected in 769 45-year old members of a population-representative cohort. Analyses revealed that variability in basic motor but not hearing ability reflected individual differences in the functional topography of neocortical networks typically supporting cognitive ability. These patterns suggest that covariation in motor and cognitive abilities in midlife reflects convergence of function in higher-order neocortical networks and that gait speed may not be simply a measure of physical function but rather an integrative index of nervous system health.

Walking pace, handgrip strength, age, APOE genotypes, and new-onset dementia: the UK Biobank prospective cohort study

BACKGROUND

The independent and additive associations of walking pace and grip strength on dementia risk and the potential modifying effects of age, APOE phenotypes, and other dementia risk factors on the walking pace and dementia relationships demand further clarification. We aimed to investigate the independent and additive relationships of walking pace and handgrip strength on the risk of new-onset dementia and examine the potentially modifying effects of age, APOE phenotypes, lifestyle factors, and family history of dementia in the relationships.

METHODS

A total of 495,700 participants from the UK Biobank, who were free of dementia at baseline, were included in this study. Walking pace was self-defined as slow, average, or brisk. Handgrip strength was assessed by dynamometer and was divided into sex-specific quartiles. The APOE genotypes were determined by a combination variant of rs429358 and rs7412. Other dementia risk factors, including education, physical activity, hypertension, depression, diabetes, and family history of dementia, were also collected. The primary outcome was new-onset all-cause dementia.

RESULTS

Over a median follow-up duration of 12.0 years, 3986 (0.8%) participants developed new-onset all-cause dementia. Compared with those with slow walking pace, participants with average (HR, 0.61; 95%CI: 0.55-0.68) or brisk (HR, 0.59; 95%CI: 0.52-0.67) walking pace had a significantly lower risk of new-onset all-cause dementia. Moreover, compared with those with both slow walking pace and lower handgrip strength (the first quartile), the lowest risk of new-onset all-cause dementia was observed in participants with both average or brisk walking pace and higher handgrip strength (the 2-4 quartiles) (HR, 0.45; 95%CI: 0.40-0.52). Notably, the negative relationship between walking pace and the risk of new-onset all-cause dementia was significantly reduced as APOE ε4 dosage increased (APOE ε4 dosages = 0 or 1: brisk vs. slow: HR, 0.55; 95%CI: 0.48-0.63; vs. APOE ε4 dosages = 2: brisk vs. slow: HR, 1.14; 95%CI: 0.77-1.68; P for interaction = 0.001) or age increased (< 58 [median]: brisk vs. slow: HR, 0.27; 95%CI: 0.18-0.41; vs. ≥ 58 years: brisk vs. slow: HR, 0.55; 95%CI: 0.48-0.63; P for interaction = 0.007).

CONCLUSIONS

Walking pace was inversely associated with new-onset dementia in the general population, especially in younger participants and those with lower APOE ε4 dosage. Participants with both faster walking pace and higher handgrip strength had the lowest risk of dementia, suggesting that maintaining both high handgrip strength and fast walking pace may be a more comprehensive strategy for preventing dementia risk.

Frailty Improvement by Multicomponent Drug, Ninjin'Yoeito, in Mild Cognitive Impairment and Mild Alzheimer's Disease Patients: An Open-Label Exploratory Study (FRAMINGO)

Background

Alzheimer's disease (AD) and dementia have increasingly been conceived of as "complex diseases of aging", determined by multiple, simultaneous, interacting pathophysiological processes. The condition known as frailty is a phenotype of aging and its comprehensive pathophysiology is thought to be closely related to the incidence of mild cognitive impairment (MCI) and the exacerbation of dementia.

Objective

This study aimed to investigate the effect of the multicomponent drug, ninjin'yoeito (NYT), on frailty in MCI and mild AD patients.

Methods

This study was an open-label trial. A total of 14 patients, including 9 with MCI and 5 with mild AD, were enrolled. Among them, 11 were frail while 3 were prefrail. NYT (6-9 g/day) was administered orally for 24 weeks, and assessments were carried out at baseline (week 0), and at 4, 8, 16, and 24 weeks.

Results

In the primary endpoint, significant early improvements were observed in the anorexia scores according to the Neuropsychiatric Inventory after four weeks of treatment with NYT. The Cardiovascular Health Study score was significantly improved, and no frailty was observed after 24 weeks. The fatigue visual analog scale scores also significantly improved. The Clinical Dementia Rating and the Montreal Cognitive Assessment scores remained at baseline levels during the NYT treatment period.

Conclusion

The results suggest that NYT may be effective in the treatment of frailty, especially for anorexia and fatigue, in both MCI and mild AD patients, which would be beneficial for the prognosis of dementia.

Using Cognitive-Motor Dual-Tasks and Functional Near-Infrared Spectroscopy to Characterize Older Adults with and without Subjective Cognitive Decline

BACKGROUND

Subjective cognitive decline (SCD) refers to individuals who report persistent cognitive deficits but perform normally on neuropsychological tests. Performance may be facilitated by increased prefrontal cortex activation, known as neural compensation, and could be used to differentiate between older adults with and without SCD.

OBJECTIVE

This cross-sectional pilot study measured changes in the hemodynamic response (ΔHbO2) using functional near-infrared spectroscopy (fNIRS) as well as cognitive and motor performance during fine and gross motor dual-tasks in older adults with and without SCD.

METHODS

Twenty older adults over 60 years old with (n = 10) and without (n = 10) SCD were recruited. Two experiments were conducted using 1) gross motor walking and 2) fine motor finger tapping tasks that were paired with an n-back working memory task. Participants also completed neuropsychological assessments and questionnaires on everyday functioning.

RESULTS

Repeated measures ANOVAs demonstrated slower response times during dual-task gait compared to the single task (p = 0.032) and in the non-SCD group, slower gait speed was also observed in the dual compared to single task (p = 0.044). Response times during dual-task finger tapping were slower than the single task (p = 0.049) and greater ΔHbO2 was observed overall in the SCD compared to non-SCD group (p = 0.002).

CONCLUSIONS

Examining neural and performance outcomes revealed differences between SCD and non-SCD groups and single and dual-tasks. Greater brain activation during dual-task finger tapping may reflect neural compensation, which should be examined in a larger sample and longitudinally to better characterize SCD.

Examining the intersection of cognitive and physical function measures: Results from the brain networks and mobility (B-NET) study

Background and objectives

Although evidence exists that measures of mobility and cognition are correlated, it is not known to what extent they overlap, especially across various domains. This study aimed to investigate the intersection of 18 different objective cognitive and physical function measures from a sample of unimpaired adults aged 70 years and older.

Research design and methods

Canonical correlation analysis was utilized to explore the joint cross-sectional relationship between 13 cognitive and 6 physical function measures in the baseline visit of the Brain Networks and Mobility Function (B-NET) Study (n = 192).

Results

Mean age of participants was 76.4 years. Two synthetic functions were identified. Function 1 explained 26.3% of the shared variability between the cognition and physical function variables, whereas Function 2 explained 19.5%. Function 1 termed "cognitive and physical speed" related the expanded Short Physical Performance Battery (eSPPB), 400-m walk speed, and Dual Task gait speed measures of physical function to semantic fluency animals scores, Digit Symbol Coding (DSC), and Trail Making Test B. Function 2 termed "complex motor tasks and cognitive tasks" related the Force Plate Postural Sway Foam Task and Dual Task to the following cognitive variables: MoCA Adjusted Score, Verbal Fluency L words, Craft story immediate and delayed recall, and Trail Making Test B.

Discussion and implications

We identified groups of cognitive and physical functional abilities that were linked in cross-sectional analyses, which may suggest shared underlying neural network pathway(s) related to speed (Function 1) or complexity (Function 2).

Translational significance

Whether such neural processes decline before measurable functional losses or may be important targets for future interventions that aim to prevent disability also remains to be determined.

Gait dysfunction in Alzheimer disease

Alzheimer's disease (AD) is the most common cause of age-associated dementia and will exponentially rise in prevalence in the coming decades, supporting the parallel development of the early stage detection and disease-modifying strategies. While primarily considered as a cognitive disorder, AD also features motor symptoms, primarily gait dysfunction. Such gait abnormalities can be phenotyped across classic clinical syndromes as well as by quantitative kinematic assessments to address subtle dysfunction at preclinical and prodromal stages. As such, certain measures of gait can predict the future cognitive and functional decline. Moreover, cross-sectional and longitudinal studies have associated gait abnormalities with imaging, biofluid, and genetic markers of AD across all stages. This suggests that gait assessment is an important tool in the clinical assessment of patients across the AD spectrum, especially to help identify at-risk individuals.