Poor Gait Performance and Prediction of Dementia: Results From a Meta-Analysis

Finger motor skills and related brain regions in patients with cognitive disorder

BackgroundMotor impairment precede cognitive impairment and may be early biomarkers for dementia. We have previously reported an association between finger tapping and cognitive function; however, the link between finger motor movements and associated brain regions is unclear.ObjectiveIn this study, finger tapping movements were used to identify brain regions strongly associated with finger motor dexterity in individuals with Alzheimer's disease (AD) and mild cognitive impairment (MCI).MethodsThis exploratory, cross-sectional study included individuals with AD or MCI who underwent finger motor movement measurements and 3D magnetic resonance imaging (MRI). Voxel-based morphometry analysis was conducted using Statistical Parametric Mapping 12 and Computational Anatomy Toolbox 12 to assess gray matter volume. Correlations between MRI and finger motor parameters were analyzed using intracranial volume, Mini-Mental State Examination score, age, and sex as covariates.ResultsWe included 136 individuals (AD, 71; MCI, 65). The number of taps and the number of freezing calculated from acceleration significantly correlated with gray matter volume in motor and sensory regions, including the primary motor (BA4) and primary somatosensory (BA3, 1, 2) cortices. Many correlations with the left hemisphere were found in both left- and right-handed bimanual alternating tapping tasks.ConclusionsFinger motor dexterity in individuals with cognitive impairment is associated with gray matter volume in specific brain regions, with a pronounced correlation in the left hemisphere. These findings suggest that finger motor skills may be linked to structural brain changes.

A Narrative Review of Physical Performance Changes in Dementia: Differences between Community and Nursing Home Setting

OBJECTIVES

To investigate differences in longitudinal physical performance in individuals with dementia across care settings.

DESIGN

Narrative review.

SETTING AND PARTICIPANTS

Older adults with moderate to severe dementia residing in the community or nursing home.

METHODS

A systematic literature search was conducted in PubMed, Embase, and Web of Science. Included studies were longitudinal, with observational or care-as-usual control groups, with a follow-up ≥3 months, assessing physical performance in adults aged ≥65 years with dementia (Mini Mental State Examination score ≤20), in the community or nursing home setting. Eligibility screening and risk of bias were performed by 2 authors. We categorized physical performance-based tests into upper limb strength, lower limb strength, balance, endurance, flexibility, mobility, and combined physical performance. Physical performance changes were quantified within each study as percentage of change from baseline to follow-up, and were compared between community and nursing home setting using narrative synthesis.

RESULTS

The search yielded 7813 studies, of which 20 were included (15 from nursing homes). Five of 20 studies were classified as having high risk of bias. In the nursing home setting, physical performance decline was observed across all domains (3- to 4-month follow-up: -6.1% to -7.7%, 5- to 7.5-month follow-up: -4.6% to -30.7%, 12- to 36-month follow-up: -27.3% to -68.2%). In the community setting, only combined physical performance declined (12-24 months: -18.6% to -33.8%).

CONCLUSIONS AND IMPLICATIONS

Studies assessing longitudinal physical performance in the community and nursing home setting were identified and summarized. Physical performance declined after shorter follow-up periods across all domains in the nursing home setting, whereas in the community setting only combined physical performance declined. However, diversity in study characteristics, study populations and outcome measures, along with a deficiency of longer follow-up periods in the community setting, hamper interpretation. Future research should focus on physical performance trajectories in longitudinal within-group designs of community-dwelling individuals with dementia who transition to nursing homes.

Effects of Hand Strength and Walking Speed Combined and in Isolation on the Prediction of Cognitive Decline and Dementia in Middle-Aged and Older Adults: A Systematic Review and Meta-Analysis

OBJECTIVE

This review aims to further elucidate the relationship between reduced walking speed and grip function and cognitive decline.

DESIGN

Systematic review and meta-analysis.

SETTINGS AND PARTICIPANTS

Adults without dementia.

METHODS

Six English databases were searched from inception to January 2025. Longitudinal studies that simultaneously investigate the relationship between a decline in grip strength or walking speed and cognitive impairment or dementia were eligible. The meta-analysis was conducted using Stata 17.0. The Newcastle-Ottawa Scale and Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach were used to assess the quality of evidence in the included studies.

RESULTS

A total of 2779 articles were identified through the search strategy. After removing duplicate titles and completing screening, 10 studies were included. Random effects analysis revealed that decreases in physical function [walking speed: hazard ratio (HR), 1.34; 95% CI, 1.13-1.60] and grip strength: HR, 1.30; 95% CI, 1.14-1.49) were significantly associated with decreases in cognitive ability, and this correlation became even more pronounced when pace and grip strength were assessed jointly (HR, 2.72; 95% CI, 1.20-6.17). The results of the subgroup analysis revealed that the study location, follow-up time, cognitive assessment method, sex ratio of the subjects, and other factors affected the results of the study.

CONCLUSIONS AND IMPLICATIONS

This study suggests that grip strength and walking speed are important predictors of cognitive decline and dementia, and highlights the significance of the comprehensive assessment. Early intervention before middle-aged and older adults enter the clinical stage of dementia is needed, which requires standardized and rigorous assessment.The sequential relationships between hand strength and walking speed in relation to different developmental stages of dementia, as well as how they can be integrated with objective indicators to facilitate diagnosis, need to be further investigated.

Association between high plasma p-tau181 level and gait changes in patients with mild cognitive impairment

Previous studies on gait changes in mild cognitive impairment (MCI) are inconsistent. Alzheimer's disease (AD) plasma biomarkers, amyloid beta (Aβ) and phosphorylated-tau (p-tau), are relevant to gait disorders. This study explores gait changes in MCI and the relationship between gait performance and AD plasma biomarkers. 231 participants were recruited and stratified based on p-tau181 levels into: low p-tau181 with normal cognition (lT-NC), low p-tau181 with MCI (lT-MCI), and high p-tau181 with MCI (hT-MCI). The same cohort was subsequently stratified by Aβ42/Aβ40 levels into: high Aβ42/Aβ40 with normal cognition (hA-NC), high Aβ42/Aβ40 with MCI (hA-MCI), and low Aβ42/Aβ40 with MCI (lA-MCI). Demographic, cognitive and gait data were compared across groups. The hT-MCI and lA-MCI groups were older than the other groups. Significant differences in stride length were found between lT-NC and hT-MCI, lT-MCI and hT-MCI, but not between lT-NC and lT-MCI. Neuropsychological assessments revealed poorer performance in hT-MCI and lT-MCI groups relative to lT-NC, while global cognitive function was comparable between hT-MCI and lT-MCI groups. No such associations were observed between stride length and Aβ42/Aβ40 levels. Decreased stride length, which is generally considered to be indicative of poorer gait, was significantly associated with elevated p-tau181 levels and independent of global cognitive status. These findings highlight the potential of p-tau181 as a biomarker for tau-related motor dysfunction in MCI.

A meta-analysis of technology use and cognitive aging

The first generation who engaged with digital technologies has reached the age where risks of dementia emerge. Has technological exposure helped or harmed cognition in digital pioneers? The digital dementia hypothesis predicts that a lifetime of technology exposure worsens cognitive abilities. An alternative hypothesis is that such exposures lead to technological reserve, wherein digital technologies promote behaviours that preserve cognition. We tested these hypotheses in a meta-analysis and systematic review of studies published in Medline, PsycInfo, CINAHL, Science Direct, Scopus, Cochrane Library, ProQuest and Web of Science. Studies were included if they were observational or cohort studies focused on general digital technology use in older adults (over age 50) and included either a cognitive or dementia diagnosis outcome. We identified 136 papers that met inclusion criteria, of which 57 were compatible with odds ratio or hazard ratio meta-analysis. These studies included 411,430 adults (baseline age M = 68.7 years; 53.5% female) from cross-sectional and longitudinal observational studies (range: 1-18 years, M = 6.2 years). Use of digital technologies was associated with reduced risk of cognitive impairment (OR = 0.42, 95% CI 0.35-0.52) and reduced time-dependent rates of cognitive decline (HR = 0.74, 95% CI 0.66-0.84). Effects remained significant when accounting for demographic, socioeconomic, health and cognitive reserve proxies. All studies were evaluated for quality on the basis of a standardized checklist; the primary outcomes replicated when limiting analyses to the highest-quality studies. Additional work is needed to test bidirectional causal interpretations, understand mechanisms that underpin technological reserve, and identify how types and timings of technology exposures influence cognitive health.

Longitudinal investigation of gait and Alzheimer's disease in adults with Down syndrome

INTRODUCTION

Gait abnormalities are associated with Alzheimer's disease (AD) in the general population, but it is unclear if the same is true for individuals with Down syndrome (DS). This study examined gait across 32 months in relation to neuroimaging biomarkers (amyloid beta [Aβ], neurofibrillary tangles [NFTs], and hippocampal volume), cognitive decline, and clinical AD status in adults with DS.

METHODS

Participants were 218 adults with DS who underwent Aβ and NFT positron emission tomography (PET) and magnetic resonance imaging (MRI) scans, cognitive testing, and gait assessments at baseline and 32 months. Residual change regression models were conducted.

RESULTS

Higher baseline Aβ PET and NFT PET and lower MRI hippocampal volume were associated with gait declines across 32 months. Cognitive declines were associated with gait declines. Participants with clinical dementia at 32 months had greater gait decline than those who were cognitively stable.

DISCUSSION

Gait impairments are a key feature of DS-associated AD (DSAD). Gait assessments could offer a quick, cost-effective, non-invasive screen for DSAD.

HIGHLIGHTS

Those with clinical status of dementia had lower gait performance than those who were cognitively stable. Higher baseline amyloid beta and neurofibrillary tangle volume was associated with more gait impairments. Lower baseline hippocampal volume was associated with more gait impairments. Greater decline in gait performance was associated with cognitive decline. Greater decline in gait performance was associated with more dementia symptoms.

Association of sarcopenia with regional brain atrophy and white matter lesions in a general older population: the Hisayama Study

Sarcopenia has been reported to be associated with cognitive decline and the risk of dementia. However, few studies have addressed the association between sarcopenia and brain morphological changes in the general population. A total of 1373 community-dwelling participants aged ≥ 65 years underwent brain MRI. Sarcopenia was defined based on the Asian Working Group for Sarcopenia's criteria. The pattern of regional gray matter volume loss associated with sarcopenia were assessed using a voxel-based morphometry (VBM) analysis. Regional brain volumes, intracranial volumes (ICV), and white matter lesions volumes (WMLV) were also measured using FreeSurfer. An analysis of covariance was used to examine the associations of sarcopenia with regional brain volumes in proportion to ICV. Of the participants, 112 had sarcopenia. The participants with sarcopenia had significantly lower total brain volume/ICV and total gray matter volume/ICV and higher WMLV/ICV than those without sarcopenia after adjusting for confounders. In VBM, sarcopenia was associated with lower gray matter volume in the frontal lobe, insula, cingulate gyrus, hippocampus, amygdala, and basal ganglia. Using FreeSurfer, we confirmed that the participants with sarcopenia had significantly lower frontal, insular, cingulate, and hippocampal volumes than those without sarcopenia. The current study showed that participants with sarcopenia had significantly lower volume in the frontal lobe, insula, cingulate, and hippocampus and higher WMLV than participants without sarcopenia. As these brain regions are likely to play an important role in cognitive function, these changes may suggest a shared underlying mechanism for the progression of sarcopenia and cognitive decline.

Louis EK, Lowe VJ, Petersen RC, Ali F, Ehgoetz Martens K. Identifying gait differences between Alzheimer's disease and dementia with Lewy bodies and their associations with regional amyloid deposition

INTRODUCTION

We aimed to compare gait between individuals with Alzheimer's disease (AD), dementia with Lewy bodies (DLB), and cognitively unimpaired (CU) individuals and to evaluate the association between gait and regional amyloid beta (Aβ) burden in AD and DLB.

METHODS

We included 420 participants (70 AD, 70 DLB, 280 CU) in the Mayo Clinic Study of Aging (MCSA). Gait was assessed using a pressure-sensor walkway. Aβ deposition was analyzed with Pittsburgh compound B (PiB) positron emission topography (PET).

RESULTS

The DLB group had reduced stride velocity, step length, and stride width variability, as well as increased double support percentage (%DS) and variability in step length, swing time, and step time compared to the AD and CU groups. Aβ burden was not associated with any gait outcomes.

DISCUSSION

This study provides additional evidence that gait differs between AD and DLB. Larger studies are needed to investigate associations between Aβ burden and gait outcomes in dementia.

HIGHLIGHTS

Gait was more impaired in dementia than in cognitively unimpaired (CU) controls. Compared with Alzheimer's disease (AD), Dementia with Lewy bodies (DLB) had more impaired pace, variability, and postural control. Step length and double support (%) distinguished DLB and AD with moderate accuracy.

Daily-life walking speed, running duration and bedtime from wrist-worn sensors predict incident dementia: A watch walk - UK biobank study

OBJECTIVE

To determine if wrist-worn sensor parameters can predict incident dementia in individuals aged 60 + years and to compare prediction with other tools.

DESIGN

Observational cohort study.

SETTING

Community PARTICIPANTS: The cohort comprised 47,371 participants without dementia, aged 60 + years, who participated in the UK Biobank study (mean age=67 ± 4 years; 52 % female).

MEASUREMENTS

Nineteen digital biomarkers were extracted from up-to-7-day wrist-worn sensor accelerometry data at baseline. Univariable and multivariable Cox proportional hazard models examined associations between sensor parameters and prospectively diagnosed dementia.

RESULTS

Median follow-up was 7.5 years (interquartile range: 7.0 to 9.0 years), during this time 387 participants (0.8 %) were diagnosed with dementia. Among the gait parameters, slower maximal walking speed had the strongest association with incident dementia (32 % decrease in hazard for each standard deviation increase) followed by lower daily step counts (30 % decrease) and increased step-time variability (17 % increase). While adjusting for age and sex, running duration, maximal walking speed and early bedtime were identified as independent and significant predictors of dementia. The multivariable prediction model performed comparably to the ANU-ADRI and UKB-Dementia Risk Score models in the UK Biobank cohort.

CONCLUSIONS

The study findings indicate that remotely acquired parameters from wrist-worn sensors can predict incident dementia. Since wrist-worn sensors are highly acceptable for long-term use, wrist-worn sensor parameters have the potential to be incorporated into dementia screening programs.

The Alzheimer's Association clinical practice guideline for the diagnostic evaluation, testing, counseling, and disclosure of suspected Alzheimer's disease and related disorders (DETeCD-ADRD): Validated clinical assessment instruments

US clinical practice guidelines for the diagnostic evaluation of cognitive impairment due to Alzheimer's Disease (AD) or AD and related dementias (ADRD) are decades old and aimed at specialists. This evidence-based guideline was developed to empower all-including primary care-clinicians to implement a structured approach for evaluating a patient with symptoms that may represent clinical AD/ADRD. As part of the modified Delphi approach and guideline development process (7374 publications were reviewed; 133 met inclusion criteria) an expert workgroup developed recommendations as steps in a patient-centered evaluation process. The workgroup provided a summary of validated instruments to measure symptoms in daily life (including cognition, mood and behavior, and daily function) and to test for signs of cognitive impairment in the office. This article distills this information to provide a resource to support clinicians in the implementation of this approach in clinical practice. The companion articles provide context for primary care and specialty clinicians with regard to how to fit these instruments into the workflow and actions to take when integration of performance on these instruments with clinical profile and clinician judgment support potential cognitive impairment.

Motor abilities and cognitive performance in Latinos with autosomal dominant Alzheimer's disease

BACKGROUND

Declining motor abilities might be a noninvasive biomarker for Alzheimer's disease (AD). Studying motor ability and AD progression in younger Latinos with autosomal dominant Alzheimer's disease (ADAD) can provide insights into the interplay between motor ability and cognition in individuals with minimal confounding from age-normative changes and comorbid medical conditions.

OBJECTIVES

This study aimed to (1) examine motor abilities as a function of years to dementia diagnosis and (2) examine associations between motor ability and cognitive performance.

DESIGN

This was a cross-sectional observational study.

SETTING

The study took place at the University of Southern California.

PARTICIPANTS

39 predominately Latino individuals (mean age 38.6 ± 10 years old) known to carry (carriers; n=25) or be at 50% risk for inheriting ADAD but not carrying the mutation (noncarriers; n=14).

MEASUREMENTS

Individuals completed the motor and cognitive batteries from the National Institute of Health Toolbox (NIHTB) and the Cognitive Abilities Screening Instrument (CASI). All models included effects for age, education, primary language, and sex.

RESULTS

Compared to noncarriers, ADAD mutation carriers had significantly weaker grip strength at 12 years, worse manual dexterity at 10 years, and slower gait speed seven years before the expected age of dementia diagnosis. Worse motor ability was associated with a more severe cognitive disease stage and worse CASI performance, adjusting for demographic and clinical variables.

CONCLUSIONS

The findings support the utility of motor performance, precisely grip strength, manual dexterity, and gait speed as potential biomarkers of preclinical AD.

Distinctive Gait Variations and Neuroimaging Correlates in Alzheimer's Disease and Cerebral Small Vessel Disease

BACKGROUND

Both Alzheimer's disease (AD) and cerebral small vessel disease (CSVD) manifest in cognitive impairment and gait disorders. The precise similarities and differences in gait characteristics and underlying neuroimaging mechanisms remain unclear.

METHODS

A total of 399 participants were enrolled: 132 with probable AD, including 98 with mild cognitive impairment due to AD (AD-MCI) and 34 with AD dementia, and 185 with CSVD and 82 healthy controls. CSVD patients with cognitive impairment, including subcortical vascular mild cognitive impairment (svMCI) and subcortical vascular dementia, were grouped as subcortical vascular cognitive impairment (SVCI). Voxel-based morphology analysis assessed grey matter volume (GMV), while cerebral blood flow (CBF) was derived from 3D-arterial spin labelling data. Gait metrics included the timed up and go (TUG) test, dual-task TUG (DTUG) test, Berg balance scale (BBS), dual-task cost (DTC), step length, gait speed, cadence and coefficient of variation of gait. The relationships among structural and perfusion variations, gait metrics and cognitive function were examined.

RESULTS

SVCI patients exhibited greater gait impairments and variability than those with AD, while AD patients experienced higher DTC (p < 0.05). These differences were most evident in the MCI stage. In AD, gait speed correlated with GMV in the left middle occipital gyrus (F = 6.149), middle temporal gyrus (F = 4.595), right precuneus (F = 5.174) and other regions (all p < 0.025). In SVCI, gait speed was linked to thalamic GMV (F = 6.004, p < 0.025). Altered CBF in the parietal lobe and precuneus was associated with DTUG (F = 5.672), gait speed (F = 4.347) and BBS (F = 4.153) in AD, while cerebellar CBF related to TUG (F = 6.042), DTUG (F = 4.857) and BBS (F = 7.097) in SVCI (all p < 0.025). In AD-MCI, memory mediated the effect of hippocampal volume on DTC (indirect effect: -2.432, 95% CI [-5.503, -0.438]), while executive function (indirect effect: -2.920, 95% CI [-7.227, -0.695]) and processing speed (indirect effect: -2.286, 95% CI [-5.174, -0.484]) mediated the effect on DTUG. In svMCI, executive function mediated the effect of thalamic volume on step length (indirect effect: 2.309, 95% CI [0.486, 4.685]) and gait speed (indirect effect: 2.029, 95% CI [0.142, 4.588]), while processing speed mediated the effect on step length (indirect effect: 1.777, 95% CI [0.311, 4.021]).

CONCLUSIONS

Different gait disorder characteristics and mechanisms were observed in AD and CSVD patients. In AD, gait is associated with volume/perfusion in posterior brain regions, whereas in SVCI, it relates to thalamic volume and cerebellar perfusion. Cognitive impairment mediates the effect of hippocampal and thalamic volumes on gait in AD-MCI and svMCI, respectively.

Development and validation of a nomogram for predicting motoric cognitive risk syndrome among community-dwelling older adults in China: a cross-sectional study

Background

Motoric cognitive risk (MCR) syndrome is characterized by slow gait speed and subjective cognitive complaints (SCC) and increases the risk of dementia and mortality.

Objective

This study aimed to examine the clinical risk factors and prevalence of MCR in community-dwelling older adults, with the goal of developing and validating a nomogram model for developing prevention strategies against MCR.

Methods

We enrolled community-dwelling participants aged 60-85 years at Guangwai Community Health Service Center between November 2023 and January 2024. A total of 1,315 older adults who met the criteria were randomly divided into a training set (n = 920) and a validation set (n = 395). By using univariate and stepwise logistic regression analysis in the training set, the MCR nomogram prediction model was developed. The area under the receiver operator characteristic curve (AUC), calibration plots, and Hosmer-Lemeshow goodness of fit test were used to evaluate the nomogram model's predictive performance, while decision curve analysis (DCA) was used to evaluate the model's clinical utility.

Results

Education, physical exercise, hyperlipoidemia, osteoarthritis, depression, and Time Up and Go (TUG) test time were identified as independent risk factors and were included to develop a nomogram model. The model exhibited high accuracy with AUC values of 0.909 and 0.908 for the training and validation sets, respectively. Calibration curves confirmed the model's reliability, and DCA highlighted its clinical utility.

Conclusion

This study constructs a nomogram model for MCR with high predictive accuracy, which provides a reference for large-scale early identification and screening of high-risk groups for MCR.

The Association Between Mild Cognitive Impairment and Physical Function in Older Japanese Adults Aged 75 Years or Older Living in Independent Senior Housing: A Cross-Sectional Study

Background/Objective: Although there are many reports on the association between cognitive and physical functions in older adults, little information is available on those aged ≥75 years. Therefore, this study aimed to determine whether mild cognitive impairment (MCI) in older adults over 75 years who live in independent senior housing is associated with physical function. Methods: In this study, 271 participants (174 women and 97 men) with a mean age of 85.4 ± 4.7 years were included. Cognitive function was assessed using the Japanese version of the Montreal Cognitive Assessment; a score < 26 confirmed MCI. MCI was an objective variable in univariate and multivariable logistic regression analyses. Physical function was measured using hand grip strength, normal and maximum gait speeds, and the 30 s chair stand test. Physical function was an explanatory variable adjusted for age and divided into tertiles (high, middle, and low) based on sex. The significance level was set at 5%. Results: There were 170 participants (63%) with MCI. Compared to the non-MCI group, the MCI group had significantly higher age and significantly lower normal and maximum gait speeds and 30 s chair stand test values Age-adjusted univariate analyses in women showed higher MCI rates in the low-fitness group than in the high-fitness group for maximum gait speed and 30 s chair stand test values. No variables were associated with MCI in men. Conclusions: MCI may be associated with physical function in women and older adults over 75 years who live in independent senior housing.

Cognitive reserve proxies are associated with age-related cognitive decline - Not age-related gait speed decline

Cognition and gait share brain substrates in aging and dementia. Cognitive reserve (CR) allows individuals to cope with brain pathology and delay cognitive impairment and dementia. Yet, evidence for that CR is associated with age-related cognitive decline is mixed, and evidence for that CR is associated with age-related gait decline is limited. In 1,079 older (M Age = 75.4 years; 56.0% women) LonGenity study participants without dementia at baseline and up to 12 years of annual follow-up (M follow-up = 3.9 years, SD = 2.5 years), high CR inferred from cognitive (education years), physical (number of blocks walked per day; weekly physical activity days), and social (volunteering/working; living with someone) proxies were associated with slower rates of age-related decline in global cognition - not gait speed decline. Thus, cognitive, physical, and social CR proxies are associated with cognitive decline in older adults without dementia. The multifactorial etiology and earlier decline in gait than cognition may render it less modifiable by CR proxies later in life.

Balance, Strength, and Risk of Dementia: Findings From the Health and Retirement Study and the English Longitudinal Study of Ageing

BACKGROUND

Slow gait speed has been consistently associated with an increased risk of dementia. This study examined whether measures of balance and lower limb strength are similarly related to the risk of developing dementia.

METHODS

Participants from the Health and Retirement Study (HRS, N = 5 658, mean age = 73.23, standard deviation [SD] = 6.22) and the English Longitudinal Study of Ageing (ELSA, N = 3667, mean age = 69.90, SD = 7.02) completed measures of gait speed, semi-tandem balance, chair stand (ELSA only), and cognitive status at baseline. Cognitive status was assessed over up to 15 years.

RESULTS

Baseline slower gait speed (hazard ratio [HR]HRS = 1.52, 95% confidence interval [CI] = 1.32-1.75, p < .001; HRELSA = 1.73, 95% CI = 1.37-2.18, p < .001); and balance impairment (HRHRS = 1.58, 95% CI = 1.26-1.96, p < .001; HRELSA = 1.97, 95% CI = 1.24-3.14, p < .01) were related to a higher risk of incident dementia, adjusting for demographic factors. The combination of slower gait and impaired balance was associated with a two-to-three times higher risk of dementia in HRS and ELSA. Worse performance on the chair stand at baseline was associated with a higher risk of dementia in ELSA (HR = 1.56, 95% CI = 1.23-1.99, p < .001). All performance measures remained significant when entered simultaneously and accounted for obesity, diabetes, blood pressure, physical activity, smoking, and depressive symptoms. There was little evidence that age, sex, or APOE ε4 moderated the association.

CONCLUSIONS

Similar to gait speed, measures of balance and strength are associated with a higher risk of incident dementia. The findings have implications for clinical practice, given that these routinely used geriatric assessment tools are similarly related to dementia risk.

A validation study demonstrating portable motion capture cameras accurately characterize gait metrics when compared to a pressure-sensitive walkway

Digital quantification of gait can be used to measure aging- and disease-related decline in mobility. Gait performance also predicts prognosis, disease progression, and response to therapies. Most gait analysis systems require large amounts of space, resources, and expertise to implement and are not widely accessible. Thus, there is a need for a portable system that accurately characterizes gait. Here, depth video from two portable cameras accurately reconstructed gait metrics comparable to those reported by a pressure-sensitive walkway. 392 research participants walked across a four-meter pressure-sensitive walkway while depth video was recorded. Gait speed, cadence, and step and stride durations and lengths strongly correlated (r > 0.9) between modalities, with root-mean-squared-errors (RMSE) of 0.04 m/s, 2.3 steps/min, 0.03 s, and 0.05-0.08 m for speed, cadence, step/stride duration, and step/stride length, respectively. Step, stance, and double support durations (gait cycle percentage) significantly correlated (r > 0.6) between modalities, with 5% RMSE for step and stance and 10% RMSE for double support. In an exploratory analysis, gait speed from both modalities significantly related to healthy, mild, moderate, or severe categorizations of Charleson Comorbidity Indices (ANOVA, Tukey's HSD, p < 0.0125). These findings demonstrate the viability of using depth video to expand access to quantitative gait assessments.

Antihypertensive Medication and Fracture Risk in Older Veterans Health Administration Nursing Home Residents

Importance

Limited evidence exists on the association between initiation of antihypertensive medication and risk of fractures in older long-term nursing home residents.

Objective

To assess the association between antihypertensive medication initiation and risk of fracture.

Design, Setting, and Participants

This was a retrospective cohort study using target trial emulation for data derived from 29 648 older long-term care nursing home residents in the Veterans Health Administration (VA) from January 1, 2006, to October 31, 2019. Data were analyzed from December 1, 2021, to November 11, 2023.

Exposure

Episodes of antihypertensive medication initiation were identified, and eligible initiation episodes were matched with comparable controls who did not initiate therapy.

Main Outcome and Measures

The primary outcome was nontraumatic fracture of the humerus, hip, pelvis, radius, or ulna within 30 days of antihypertensive medication initiation. Results were computed among subgroups of residents with dementia, across systolic and diastolic blood pressure thresholds of 140 and 80 mm Hg, respectively, and with use of prior antihypertensive therapies. Analyses were adjusted for more than 50 baseline covariates using 1:4 propensity score matching.

Results

Data from 29 648 individuals were included in this study (mean [SD] age, 78.0 [8.4] years; 28 952 [97.7%] male). In the propensity score-matched cohort of 64 710 residents (mean [SD] age, 77.9 [8.5] years), the incidence rate of fractures per 100 person-years in residents initiating antihypertensive medication was 5.4 compared with 2.2 in the control arm. This finding corresponded to an adjusted hazard ratio (HR) of 2.42 (95% CI, 1.43-4.08) and an adjusted excess risk per 100 person-years of 3.12 (95% CI, 0.95-6.78). Antihypertensive medication initiation was also associated with higher risk of severe falls requiring hospitalizations or emergency department visits (HR, 1.80 [95% CI, 1.53-2.13]) and syncope (HR, 1.69 [95% CI, 1.30-2.19]). The magnitude of fracture risk was numerically higher among subgroups of residents with dementia (HR, 3.28 [95% CI, 1.76-6.10]), systolic blood pressure of 140 mm Hg or higher (HR, 3.12 [95% CI, 1.71-5.69]), diastolic blood pressure of 80 mm Hg or higher (HR, 4.41 [95% CI, 1.67-11.68]), and no recent antihypertensive medication use (HR, 4.77 [95% CI, 1.49-15.32]).

Conclusions and Relevance

Findings indicated that initiation of antihypertensive medication was associated with elevated risks of fractures and falls. These risks were numerically higher among residents with dementia, higher baseline blood pressures values, and no recent antihypertensive medication use. Caution and additional monitoring are advised when initiating antihypertensive medication in this vulnerable population.

CLADSI: Deep Continual Learning for Alzheimer's Disease Stage Identification Using Accelerometer Data

Alzheimer's disease (AD) is a neurodegenerative disorder that can cause a significant impairment in physical and cognitive functions. Gait disturbances are also reported as a symptom of AD. Previous works have used Convolutional Neural Networks (CNNs) to analyze data provided by motion sensors that monitor Alzheimer's patients. However, these works have not explored continual learning algorithms that allow the CNN to configure itself as it receives new data from these sensors. This work proposes a method aimed at enabling CNNs to learn from a continuous stream of data from motion sensors without having full access to previous data. The CNN identifies the stage of AD from the analysis of data provided by motion sensors. The work includes an experimentation with data captured by accelerometers that monitored the activity of 35 Alzheimer's patients for a week in a daycare center. The CNN achieves an accuracy of 86,94%, 86,48% and 84,37% for 2, 3 and 4 experiences respectively. The proposal provides advantages to working with a continuous stream of data so that the CNN are constantly self-configuring without the intervention of a human. The work can be considered as promising and helpful in finding deep learning solutions in medical cases in which patients are constantly monitored.

Cognitive trajectories preluding the onset of different dementia entities: a descriptive longitudinal study using the NACC database

OBJECTIVE

To describe the 10-year preclinical cognitive trajectories of older, non-demented individuals towards the onset of the four most prevalent types of dementia, i.e., Alzheimer's disease(AD), Lewy body(LBD), vascular(VD) and frontotemporal dementia(FTD).

METHODS

Our analysis focused on data from older (≥ 60years) NACC (National Alzheimer's Coordinating Center) participants. Four distinct presymptomatic dementia groups (AD-LBD-VD-FTD) and a comparison group of cognitively unimpaired(CU) participants were formed. Comprehensive cognitive assessments involving verbal episodic memory, semantic verbal fluency, confrontation naming, mental processing speed - attention and executive function - cognitive flexibility were conducted at baseline and on an approximately yearly basis. Descriptive analyses (adjusted general linear models) were performed to determine and compare the yearly cognitive scores of each group throughout the follow-up. Exploratory analyses were conducted to estimate the rates of cognitive decline.

RESULTS

There were 3343 participants who developed AD, 247 LBD, 108 FTD, 155 VD and 3398 composed the CU group. Participants with AD performed worse on episodic memory than those with VD and LBD for about 3 to 4 years prior to dementia onset (the FTD group documented an intermediate course). Presymptomatic verbal fluency and confrontation naming trajectories differentiated quite well between the FTD group and the remaining dementia entities. Participants with incident LBD and VD performed worse than those with AD on executive functions and mental processing speed-attention since about 5 years prior to the onset of dementia, and worse than those with FTD more proximally to the diagnosis of the disorder.

CONCLUSIONS

Heterogeneous cognitive trajectories characterize the presymptomatic courses of the most prevalent dementia entities.

The time course of motor and cognitive decline in older adults and their associations with brain pathologies: a multicohort study

BACKGROUND

Many studies have reported that impaired gait precedes cognitive impairment in older people. We aimed to characterise the time course of cognitive and motor decline in older individuals and the association of these declines with the pathologies of Alzheimer's disease and related dementias.

METHODS

This multicohort study used data from three community-based cohort studies (Religious Orders Study, Rush Memory and Aging Project, and Minority Aging Research Study, all in the USA). The inclusion criteria for all three cohorts were no clinical dementia at the time of enrolment and consent to annual clinical assessments. Eligible participants consented to post-mortem brain donation and had post-mortem pathological assessments and three or more repeated annual measures of cognition and motor functions. Clinical and post-mortem data were analysed using functional mixed-effects models. Global cognition was based on 19 neuropsychological tests, a hand strength score was based on grip and pinch strength, and a gait score was based on the number of steps and time to walk 8 feet and turn 360°. Brain pathologies of Alzheimer's disease and related dementias were assessed at autopsy.

FINDINGS

From 1994 to 2022, there were 1570 eligible cohort participants aged 65 years or older, 1303 of whom had cognitive and motor measurements and were included in the analysis. Mean age at death was 90·3 years (SD 6·3), 905 (69%) participants were female, and 398 (31%) were male. Median follow-up time was 9 years (IQR 5-11). On average, cognition was stable from 25 to 15 years before death, when cognition began to decline. By contrast, gait function and hand strength declined during the entire study. The combinations of pathologies of Alzheimer's disease and related dementias associated with cognitive and motor decline and their onsets of associations varied; only tau tangles, Parkinson's disease pathology, and macroinfarcts were associated with decline of all three phenotypes. Tau tangles were significantly associated with cognitive decline, gait function decline, and hand function decline (p<0·0001 for each); however, the association with cognitive decline persisted for more than 11 years before death, but the association with hand strength only began 3·57 years before death and the association with gait began 3·49 years before death. By contrast, the association of macroinfarcts with declining gait function began 9·25 years before death (p<0·0001) compared with 6·65 years before death (p=0·0005) for cognitive decline and 2·66 years before death (p=0·024) for decline in hand strength.

INTERPRETATION

Our findings suggest that average motor decline in older adults precedes cognitive decline. Macroinfarcts but not tau tangles are associated with declining gait function that precedes cognitive decline. This suggests the need for further studies to test if gait impairment is a clinical proxy for preclinical vascular cognitive impairment.

FUNDING

National Institutes of Health.

Association of 8-hydroxy-2'-deoxyguanosine with motoric cognitive risk in elderly Chinese people: RUGAO longevity and aging cross-sectional study

BACKGROUND

Motor cognitive risk syndrome (MCR) represents a critical pre-dementia and disability state characterized by a combination of objectively measured slow walking speed and subjective memory complaints (SMCs). This study aims to identify risk factors for MCR and investigate the relationship between plasma levels of 8-hydroxy-2'-deoxyguanosine (8-OHdG) and MCR among Chinese community-dwelling elderly populations.

METHODS

A total of 1312 participants were involved in this study based on the data of the Rugao Longevity and Aging Study (RuLAS). The MCR was characterized by SMCs and slow walking speed. The SCCs were defined as a positive answer to the question 'Do you feel you have more problems with memory than most?' in a 15-item Geriatric Depression Scale. Slow walking speed was determined by one standard deviation or more below the mean value of the patient's age and gender group. The plasma of 8-OHdG were measured by a technician in the biochemistry laboratory of the Rugao People's Hospital during the morning of the survey.

RESULTS

The prevalence of MCR was found to be 7.9%. After adjusting for covariates, significant associations with MCR were observed in older age (OR 1.057; p = 0.018), history of cerebrovascular disease (OR 2.155; p = 0.010), and elevated 8-OHdG levels (OR 1.007; p = 0.003).

CONCLUSIONS

This study indicated the elevated plasma 8-OHdG is significantly associated with increased MCR risk in the elderly, suggesting its potential as a biomarker for early detection and intervention in MCR. This finding underscores the importance of monitoring oxidative DNA damage markers in predicting cognitive and motor function declines, offering new avenues for research and preventive strategies in aging populations.

Postural Control Characteristics in Alzheimer's Disease, Dementia With Lewy Bodies, and Vascular Dementia

BACKGROUND

Dementia often results in postural control impairment, which could signify central nervous system dysfunction. However, no studies have compared postural control characteristics among various types of dementia. This study aimed to compare static postural control in patients with Alzheimer's disease (AD), dementia with Lewy bodies (DLB), and vascular dementia (VaD).

METHODS

Cross-sectional relationship between the clinical diagnoses (AD, DLB, VaD, or normal cognition [NC]) of outpatients at a memory clinic and their upright postural control characteristics were examined. In the postural control test, participants were instructed to maintain a static upright standing on a stabilometer for 60 seconds under the eyes-open and eyes-closed conditions. Forty postural control parameters, including distance, position, and velocity in the anterior-posterior and medio-lateral directions, derived from the trajectory of the center of mass sway, were calculated. The characteristics of each type of dementia were compared to those of NC, and the differences among the 3 types of dementia were evaluated using linear regression models.

RESULTS

The study included 1 789 participants (1 206 with AD, 111 with DLB, 49 with VaD, and 423 with NC). Patients with AD exhibited distinct postural control characteristics, particularly in some distance and velocity parameters, only in the eyes-closed condition. Those with DLB exhibited features in the mean position in the anterior-posterior direction. In patients with VaD, significant differences were observed in most parameters, except the power spectrum.

CONCLUSIONS

Patients with AD, DLB, and VaD display disease-specific postural control characteristics when compared to cognitively normal individuals.

Sensory and motor deficits as contributors to early cognitive impairment

INTRODUCTION

Age-related sensory and motor impairment are associated with risk of dementia. No study has examined the joint associations of multiple sensory and motor measures on prevalence of early cognitive impairment (ECI).

METHODS

Six hundred fifty participants in the Baltimore Longitudinal Study of Aging completed sensory and motor function tests. The association between sensory and motor function and ECI was examined using structural equation modeling with three latent factors corresponding to multisensory, fine motor, and gross motor function.

RESULTS

The multisensory, fine, and gross motor factors were all correlated (r = 0.74 to 0.81). The odds of ECI were lower for each additional unit improvement in the multisensory (32%), fine motor (30%), and gross motor factors (12%).

DISCUSSION

The relationship between sensory and motor impairment and emerging cognitive impairment may guide future intervention studies aimed at preventing and/or treating ECI.

HIGHLIGHTS

Sensorimotor function and early cognitive impairment (ECI) prevalence were assessed via structural equation modeling. The degree of fine and gross motor function is associated with indicators of ECI. The degree of multisensory impairment is also associated with indicators of ECI.

Presymptomatic Profiles of Cognitive Impairment with Prior Mobility Impairment

OBJECTIVES

To identify cognitive and health profiles of cognitively impaired older adults with the presence of prior mobility impairment, which may represent a specific pathway to the development of cognitive impairment or dementia.

DESIGN

Retrospective longitudinal study.

SETTING AND PARTICIPANTS

In adults aged ≥65 years who developed cognitive impairment or dementia, we compared cognitive and health profiles of those who did (n = 57) and did not (n = 86) experience slow gait up to 14 years before symptom onset. Measures of cognitive and biomarkers assessed longitudinally over an average of 7 years before symptom onset were compared between groups using linear mixed effects models, adjusted age, sex, race, and additionally adjusted for education for cognitive outcomes.

RESULTS

Compared to those without prior slow gait, those with slow gait had lower Digit Symbol Substitution Test and Pegboard dominant and nondominant hand performance. The slow gait group also had greater body mass index (BMI), waist, systolic blood pressure, lower high-density lipoprotein and low-density lipoprotein, and lower lysophosphatidylcholine 18:2, a lipid associated with mitochondrial function, and showed greater increases in 2-hour glucose levels of an oral glucose tolerance test. The slow gait group was more likely to take medication for hypertension and hypercholesterolemia.

CONCLUSIONS AND IMPLICATIONS

During the presymptomatic stage, cognitively impaired older persons who experience prior slow gait are more likely to have deficits in psychomotor speed and manual dexterity, an unfavorable metabolic and vascular profile, and lower lipid levels related to mitochondrial function. Older persons who exhibit mobility impairment should be evaluated for metabolic and vascular dysfunction at an early stage, and successful treatment of these conditions may slow down the progression of cognitive impairment or dementia.

Feasibility of Identifying Factors Related to Alzheimer's Disease and Related Dementia in Real-World Data

A comprehensive view of factors associated with AD/ADRD will significantly aid in studies to develop new treatments for AD/ADRD and identify high-risk populations and patients for prevention efforts. In our study, we summarized the risk factors for AD/ADRD by reviewing existing meta-analyses and review articles on risk and preventive factors for AD/ADRD. In total, we extracted 477 risk factors in 10 categories from 537 studies. We constructed an interactive knowledge map to disseminate our study results. Most of the risk factors are accessible from structured Electronic Health Records (EHRs), and clinical narratives show promise as information sources. However, evaluating genomic risk factors using RWD remains a challenge, as genetic testing for AD/ADRD is still not a common practice and is poorly documented in both structured and unstructured EHRs. Considering the constantly evolving research on AD/ADRD risk factors, literature mining via NLP methods offers a solution to automatically update our knowledge map.

Comparative study of machine learning methods for modeling associations between risk factors and future dementia cases

A substantial portion of dementia risk can be attributed to modifiable risk factors that can be affected by lifestyle changes. Identifying the contributors to dementia risk could prove valuable. Recently, machine learning methods have been increasingly applied to healthcare data. Several studies have attempted to predict dementia progression by using such techniques. This study aimed to compare the performance of different machine-learning methods in modeling associations between known cognitive risk factors and future dementia cases. A subset of the AGES-Reykjavik Study dataset was analyzed using three machine-learning methods: logistic regression, random forest, and neural networks. Data were collected twice, approximately five years apart. The dataset included information from 1,491 older adults who underwent a cognitive screening process and were considered to have healthy cognition at baseline. Cognitive risk factors included in the models were based on demographics, MRI data, and other health-related data. At follow-up, participants were re-evaluated for dementia using the same cognitive screening process. Various performance metrics for all three machine learning algorithms were assessed. The study results indicate that a random forest algorithm performed better than neural networks and logistic regression in predicting the association between cognitive risk factors and dementia. Compared to more traditional statistical analyses, machine-learning methods have the potential to provide more accurate predictions about which individuals are more likely to develop dementia than others.

Mid-Life Vascular Risk and Rate of Physical Function Decline Among Older Adults: The Atherosclerosis Risk in Communities (ARIC) Study

BACKGROUND

Physical function and its decline in older age may be connected to treatable vascular risk factors in mid-life. This study aimed to evaluate whether these factors affect the underlying rate of decline.

METHODS

This prospective cohort included 5 481 older adults aged 67-91 in the Atherosclerosis Risk in Communities Study (mean [standard deviation {SD}] age = 75.8 [5.0], 58% women, 21% Black race) without a history of stroke. The main outcome was the rate of Short Physical Performance Battery (SPPB) decline over a median late-life follow-up of 4.8 years. Primary mid-life (aged 45-64) exposures were Visit 1 hypertension (>140/90 mm Hg or treatment), diabetes (>126 mg/dL or treatment), high cholesterol (>240 mg/dL or treatment), and smoking, and number of decades of vascular risk exposure across Visits 1-4.

RESULTS

The average adjusted rate of SPPB decline (points per 5 years) for older adults was -0.79 (confidence interval [CI]: -0.87, 0.71) and was accelerated by mid-life hypertension (+57% decline vs normotension: additional decline of -0.47, 95% CI: -0.64, -0.30), diabetes (+73% decline vs no diabetes: additional decline of -0.67, 95% CI: -1.09, -0.24), elevated systolic blood pressure (+17% decline per SD: -0.16, 95% CI: -0.23, -0.10), and elevated fasting blood glucose (+16% decline per SD: -0.015, 95% CI: -0.24, -0.06). Each decade greater mid-life exposure to hypertension (+32% decline: -0.93, 95% CI: -1.25, -0.61) and diabetes (+35% decline: -1.03, 95% CI: -1.68, -0.38) was associated with faster SPPB decline.

CONCLUSIONS

Mid-life control of blood pressure and diabetes may offset aging-related functional decline.

Estimating presymptomatic episodic memory impairment using simple hand movement tests: A cross-sectional study of a large sample of older adults

INTRODUCTION

Finding low-cost methods to detect early-stage Alzheimer's disease (AD) is a research priority for neuroprotective drug development. Presymptomatic Alzheimer's is associated with gait impairment but hand motor tests, which are more accessible, have hardly been investigated. This study evaluated how home-based Tasmanian (TAS) Test keyboard tapping tests predict episodic memory performance.

METHODS

1169 community participants (65.8 ± 7.4 years old; 73% female) without cognitive symptoms completed online single-key and alternate-key tapping tests and episodic memory, working memory, and executive function cognitive tests.

RESULTS

All single-key (R2 adj  = 8.8%, ΔAIC = 5.2) and alternate-key (R2 adj  = 9.1%, ΔAIC = 8.8) motor features predicted episodic memory performance relative to demographic and mood confounders only (R2 adj  = 8.1%). No tapping features improved estimation of working memory.

DISCUSSION

Brief self-administered online hand movement tests predict asymptomatic episodic memory impairment. This provides a potential low-cost home-based method for stratification of enriched cohorts.

HIGHLIGHTS

We devised two brief online keyboard tapping tests to assess hand motor function. 1169 cognitively asymptomatic adults completed motor- and cognitive tests online. Impaired hand motor function predicted reduced episodic memory performance. This brief self-administered test may aid stratification of community cohorts.

Machine Learning Approaches for Dementia Detection Through Speech and Gait Analysis: A Systematic Literature Review

Background

Dementia is a general term for several progressive neurodegenerative disorders including Alzheimer's disease. Timely and accurate detection is crucial for early intervention. Advancements in artificial intelligence present significant potential for using machine learning to aid in early detection.

Objective

Summarize the state-of-the-art machine learning-based approaches for dementia prediction, focusing on non-invasive methods, as the burden on the patients is lower. Specifically, the analysis of gait and speech performance can offer insights into cognitive health through clinically cost-effective screening methods.

Methods

A systematic literature review was conducted following the PRISMA protocol (Preferred Reporting Items for Systematic Reviews and Meta-Analyses). The search was performed on three electronic databases (Scopus, Web of Science, and PubMed) to identify the relevant studies published between 2017 to 2022. A total of 40 papers were selected for review.

Results

The most common machine learning methods employed were support vector machine followed by deep learning. Studies suggested the use of multimodal approaches as they can provide comprehensive and better prediction performance. Deep learning application in gait studies is still in the early stages as few studies have applied it. Moreover, including features of whole body movement contribute to better classification accuracy. Regarding speech studies, the combination of different parameters (acoustic, linguistic, cognitive testing) produced better results.

Conclusions

The review highlights the potential of machine learning, particularly non-invasive approaches, in the early prediction of dementia. The comparable prediction accuracies of manual and automatic speech analysis indicate an imminent fully automated approach for dementia detection.

Association between serum iron, blood lead, cadmium, mercury, selenium, manganese and low cognitive performance in old adults from National Health and Nutrition Examination Survey (NHANES): a cross-sectional study

Cognitive decline is a public health problem for the world's ageing population. This study was to evaluate the relationships between serum Fe, blood Pb, Cd, Hg, Se and Mn and cognitive decline in elderly Americans. Data of this cross-sectional study were extracted from the National Health and Nutritional Examination Survey (NHANES 2011-2014). Cognitive performance was measured by the Consortium to Establish a Registry for Alzheimer's Disease (CERAD), Animal Fluency and Digit Symbol Substitution Test (DSST) tests. Weighted univariable and multivariate logistic regression analyses were used to assess the associations between six trace elements and low cognitive performance. Subgroup analyses based on diabetes and hypertension history were further assessed the associations. A total of 2002 adults over 60 years old were included. After adjusting covariates, elevated serum Fe levels were associated with the decreased risk of low cognitive performance, especially in the elderly without diabetes history and with hypertension history. High blood Cd levels were associated with the high odds of low cognitive performance in old adults with diabetes and hypertension history. Elevated blood Mn levels were connected with low cognitive performance in old hypertensive people. High blood Pb levels were related to the high odds of low cognitive performance, especially in the elderly without diabetes and hypertension history. High blood Se levels were linked to the decreased risk of low cognitive performance in all the elderly. Appropriate Fe, Se supplementation and Fe-, Se-rich foods intake, while reducing exposure to Pb, Cd and Mn may be beneficial for cognitive function in the elderly.

Neuromuscular assessment of force development, postural, and gait performance under cognitive-motor dual-tasking in healthy older adults and people with early Parkinson's disease: Study protocol for a cross-sectional Mobile Brain/Body Imaging (MoBI) study

Background

Neuromuscular dysfunction is common in older adults and more pronounced in neurodegenerative diseases. In Parkinson's disease (PD), a complex set of factors often prevents the effective performance of activities of daily living that require intact and simultaneous performance of the motor and cognitive tasks.

Methods

The cross-sectional study includes a multifactorial mixed-measure design. Between-subject factor grouping the sample will be Parkinson's Disease (early PD vs. healthy). The within-subject factors will be the task complexity (single- vs. dual-task) in each motor activity, i.e., overground walking, semi-tandem stance, and isometric knee extension, and a walking condition (wide vs. narrow lane) will be implemented for the overground walking activity only. To study dual-task (DT) effects, in each motor activity participants will be given a secondary cognitive task, i.e., a visual discrimination task for the overground walking, an attention task for the semi-tandem, and mental arithmetic for the isometric extension. Analyses of DT effects and underlying neuronal correlates will focus on both gait and cognitive performance where applicable. Based on an a priori sample size calculation, a total N = 42 older adults (55-75 years) will be recruited. Disease-specific changes such as laterality in motor unit behavior and cortical control of movement will be studied with high-density surface electromyography and electroencephalography during static and dynamic motor activities, together with whole-body kinematics.

Discussion

This study will be one of the first to holistically address early PD neurophysiological and neuromuscular patterns in an ecologically valid environment under cognitive-motor DT conditions of different complexities. The outcomes of the study aim to identify the biomarker for early PD either at the electrophysiological, muscular or kinematic level or in the communication between these systems.

Clinical Trial Registration

ClinicalTrials.Gov, NCT05477654. This study was approved by the Medical Ethical Committee (106/2021).

Assessing Physiologic Reserve and Frailty in the Older Emergency Department Patient: Should the Paradigm Change?

Older patients are more vulnerable to acute illness or injury because of reduced physiologic reserve associated with aging. Therefore, their assessment in the emergency department (ED) should include not only vital signs and their baseline values but also changes that reflect physiologic reserve, such as mobility, mental status, and frailty. Combining aggregated vitals sign scores and frailty might improve risk stratification in the ED. Implementing these changes in ED assessment may require the introduction of senior-friendly processes to ensure ED treatment is appropriate to the older patients' immediate discomfort, personal goals, and likely prognosis.

[Motoric cognitive risk syndrome-Setting the course for dementia prevention?]

BACKGROUND

The predicted increase in adults with dementia will pose a major challenge for the German healthcare system. To mitigate this challenge, the early detection of adults with an increased risk of dementia is crucial. In this context, the concept of motoric cognitive risk (MCR) syndrome has been introduced into the English literature but is currently relatively unknown in German-speaking countries.

OBJECTIVE

What are the characteristics and diagnostic criteria of MCR? What is the impact of MCR on health-related parameters? What is the current state of evidence regarding the risk factors and prevention of the MCR?

MATERIAL AND METHODS

We reviewed the English language literature concerning MCR, the associated risk factors, and protective factors, similarities or differences with the concept of mild cognitive impairment (MCI), and its influence on the central nervous system.

RESULTS

The MCR syndrome is characterized by subjective cognitive impairment and a slower gait speed. Compared to healthy adults, adults with the MCR have a higher risk of dementia, falls, and mortality. Modifiable risk factors provide a starting point for specific multimodal lifestyle-related preventive interventions.

CONCLUSION

As MCR can be easily diagnosed in practical settings, it could become an important concept for the early detection of adults with an increased risk of dementia in German-speaking countries, although further research is necessary to empirically confirm this assumption.

Effects of tai chi on postural balance and quality of life among the elderly with gait disorders: A systematic review

BACKGROUND

Tai Chi is good for improving the physical fitness of older adults. But few studies have reported the effects of Tai Chi on the postural balance and quality of life of older adults with gait disorders.

OBJECTIVE

This review aimed to assess the influence of tai chi on postural stability and quality of life in older adults with abnormal gait.

METHOD

According to the literature retrieval principles, the works published from the inception date to May 2023 were retrieved, including the following databases: PubMed, Scopus, Web of Science, China National Knowledge Infrastructure, EBSCOhost, and Google Scholar. Subsequently, literature screening and quality assessment were performed.

RESULTS

A total of 16 randomized controlled trials were included in this study, Tai Chi intervention can affect populations with Parkinson's disease (PD), no exercise, mild cognitive impairment (MCI), chronic stroke, sedentary, fear of falling, or history of falling. Postural instability is associated with balance, gait, the Unified Parkinson's Disease Rating Scale Motor Subscale 3 (UPDRS III), mobility, lower body strength, and falls. Only two articles looked at quality of life. The Yang style is the most commonly used in the intervention. Nonetheless, most studies were performed on female participants, hence, more research on older male populations is needed.

CONCLUSION

Tai Chi intervention benefits postural balance in patients with gait disorders. 12 weeks is the most common intervention period for patients with gait disorders. The frequency of intervention is seven articles twice a week, and the intervention time is about 60 minutes. The Tai Chi intervention methods in this study involve Yang Style, Sun Style, Taoist Tai Chi, and Health Qigong Tai Chi, but the Yang Style Tai Chi intervention is the most widely used.

Cognitive, physical and emotional determinants of activities of daily living in nursing home residents-a cross-sectional study within the PROCARE-project

BACKGROUND

Interdependencies of health, fitness, cognition, and emotion can promote or inhibit mobility. This study aimed to analyse pathways and interactions between individual subjective and objective physical performance, cognition, and emotions with activities of daily living (ADLs) as mobility indicators in multimorbid nursing home residents.

METHODS

The study included n = 448 (77.1% females, age = 84.1 ± 7.8 years) nursing home residents. To describe the participant's demographics, frailty, number of falls, and participating institutions' socioeconomic status (SES) were assessed. ADLs were measured with the Barthel Index (BI; dependent variable). Independent variables included objective physical performance, subjective physical performance, cognition, and emotions. A structural equation model (SEM) with maximum likelihood estimation was conducted with AMOS. Direct and indirect effects were estimated using standardized coefficients (significance level of 0.05).

RESULTS

Indices showed (Chi2(148) = 217, PCMIN/DF = 1.47; p < .001; Comparative Fit Index = .940; Tucker Lewes Index = .902, RMSEA = .033) that the model fitted the data adequately. While there was no direct association between emotions, subjective physical performance, and ADLs, objective physical performance and cognition predicted higher ADLs (p < .01). Emotions had a strong relationship with subjective physical performance, and cognition had a moderate relationship with objective physical performance.

DISCUSSION AND CONCLUSION

Objective performance and cognition predicted higher functional status, as expressed by higher BI scores. ADLs, such as mobility, dressing, or handling tasks, require motor and cognitive performance. Subjective performance is an important predictor of ADLs and is only partly explained by objective performance, but to a large extent also by emotions. Therefore, future interventions for nursing home residents should take a holistic approach that focuses not only on promoting objective physical and cognitive performance but also on emotions and perceived physical performance.

TRIAL REGISTRATION

Trial registration number: DRKS00014957.

Association between cognition and gait in multiple sclerosis: A smartphone-based longitudinal analysis

BACKGROUND

Gait and cognition impairments are common problems among People with Multiple Sclerosis (PwMS). Previous studies have investigated cross-sectional associations between gait and cognition. However, there is a lack of evidence regarding the longitudinal association between these factors in PwMS. Therefore, the objective of this study was to explore this longitudinal relationship using smartphone-based data from the Floodlight study.

METHODS

Using the publicly available Floodlight dataset, which contains smartphone-based longitudinal data, we used a linear mixed model to investigate the longitudinal relationship between cognition, measured by the Symbol Digit Modalities Test (SDMT), and gait, measured by the 2 Minute Walking test (2 MW) step count and Five-U-Turn Test (FUTT) turning speed. Four mixed models were fitted to explore the association between: 1) SDMT and mean step count; 2) SDMT and variability of step count; 3) SDMT and mean FUTT turning speed; and 4) SDMT and variability of FUTT turningt speed.

RESULTS

After controlling for age, sex, weight, and height, there were significant correlations between SDMT and the variability of 2 MW step count, the mean of FUTT turning speed. No significant correlation was observed between SDMT and the 2 MW mean step count.

SIGNIFICANCE

Our findings support the evidence that gait and cognition are associated in PwMS. This may support clinicians to adjust treatment and intervention programs that address both gait and cognitive impairments.

Age- and sex-dependent alterations in primary somatosensory cortex neuronal calcium network dynamics during locomotion

Over the past 30 years, the calcium (Ca2+ ) hypothesis of brain aging has provided clear evidence that hippocampal neuronal Ca2+ dysregulation is a key biomarker of aging. Age-dependent Ca2+ -mediated changes in intrinsic excitability, synaptic plasticity, and activity have helped identify some of the mechanisms engaged in memory and cognitive decline based on work done mostly at the single-cell level and in the slice preparation. Recently, our lab identified age- and Ca2+ -related neuronal network dysregulation in the cortex of the anesthetized animal. Still, investigations in the awake animal are needed to test the generalizability of the Ca2+ hypothesis of brain aging. Here, we used in vigilo two-photon imaging in ambulating mice, to image GCaMP8f in the primary somatosensory cortex (S1), during ambulation and at rest. We investigated aging- and sex-related changes in neuronal networks in the C56BL/6J mouse. Following imaging, gait behavior was characterized to test for changes in locomotor stability. During ambulation, in both young adult and aged mice, an increase in network connectivity and synchronicity was noted. An age-dependent increase in synchronicity was seen in ambulating aged males only. Additionally, females displayed increases in the number of active neurons, Ca2+ transients, and neuronal activity compared to males, particularly during ambulation. These results suggest S1 Ca2+ dynamics and network synchronicity are likely contributors of locomotor stability. We believe this work raises awareness of age- and sex-dependent alterations in S1 neuronal networks, perhaps underlying the increase in falls with age.

Prognostic relevance of gait-related cognitive functions for dementia conversion in amnestic mild cognitive impairment

BACKGROUND

Increasing research suggests that gait abnormalities can be a risk factor for Alzheimer's Disease (AD). Notably, there is growing evidence highlighting this risk factor in individuals with amnestic Mild Cognitive Impairment (aMCI), however further studies are needed. The aim of this study is to analyze cognitive tests results and brain-related measures over time in aMCI and examine how the presence of gait abnormalities (neurological or orthopedic) or normal gait affects these trends. Additionally, we sought to assess the significance of gait and gait-related measures as prognostic indicators for the progression from aMCI to AD dementia, comparing those who converted to AD with those who remained with a stable aMCI diagnosis during the follow-up.

METHODS

Four hundred two individuals with aMCI from the Alzheimer's Disease Neuroimaging Initiative (ADNI) database were included. Robust linear mixed-effects models were used to study the impact of gait abnormalities on a comprehensive neuropsychological battery over 36 months while controlling for relevant medical variables at baseline. The impact of gait on brain measures was also investigated. Lastly, the Cox proportional-hazards model was used to explore the prognostic relevance of abnormal gait and neuropsychological associated tests.

RESULTS

While controlling for relevant covariates, we found that gait abnormalities led to a greater decline over time in attention (DSST) and global cognition (MMSE). Intriguingly, psychomotor speed (TMT-A) and divided attention (TMT-B) declined uniquely in the abnormal gait group. Conversely, specific AD global cognition tests (ADAS-13) and auditory-verbal memory (RAVLT immediate recall) declined over time independently of gait profile. All the other cognitive tests were not significantly affected by time or by gait profile. In addition, we found that ventricles size increased faster in the abnormal gait group compared to the normal gait group. In terms of prognosis, abnormal gait (HR = 1.7), MMSE (HR = 1.09), and DSST (HR = 1.03) covariates showed a higher impact on AD dementia conversion.

CONCLUSIONS

The importance of the link between gait and related cognitive functions in terms of diagnosis, prognosis, and rehabilitation in aMCI is critical. We showed that in aMCI gait abnormalities lead to executive functions/attention deterioration and conversion to AD dementia.

Artificial Intelligence Distinguishes Pathological Gait: The Analysis of Markerless Motion Capture Gait Data Acquired by an iOS Application (TDPT-GT)

Distinguishing pathological gait is challenging in neurology because of the difficulty of capturing total body movement and its analysis. We aimed to obtain a convenient recording with an iPhone and establish an algorithm based on deep learning. From May 2021 to November 2022 at Yamagata University Hospital, Shiga University, and Takahata Town, patients with idiopathic normal pressure hydrocephalus (n = 48), Parkinson's disease (n = 21), and other neuromuscular diseases (n = 45) comprised the pathological gait group (n = 114), and the control group consisted of 160 healthy volunteers. iPhone application TDPT-GT captured the subjects walking in a circular path of about 1 meter in diameter, a markerless motion capture system, with an iPhone camera, which generated the three-axis 30 frames per second (fps) relative coordinates of 27 body points. A light gradient boosting machine (Light GBM) with stratified k-fold cross-validation (k = 5) was applied for gait collection for about 1 min per person. The median ability model tested 200 frames of each person's data for its distinction capability, which resulted in the area under a curve of 0.719. The pathological gait captured by the iPhone could be distinguished by artificial intelligence.

Development of a Gait Feature-Based Model for Classifying Cognitive Disorders Using a Single Wearable Inertial Sensor

BACKGROUND AND OBJECTIVES

Gait changes are potential markers of cognitive disorders (CDs). We developed a model for classifying older adults with CD from those with normal cognition using gait speed and variability captured from a wearable inertial sensor and compared its diagnostic performance for CD with that of the model using the Mini-Mental State Examination (MMSE).

METHODS

We enrolled community-dwelling older adults with normal gait from the Korean Longitudinal Study on Cognitive Aging and Dementia and measured their gait features using a wearable inertial sensor placed at the center of body mass while they walked on a 14-m long walkway thrice at comfortable paces. We randomly split our entire dataset into the development (80%) and validation (20%) datasets. We developed a model for classifying CD using logistic regression analysis from the development dataset and validated it in the validation dataset. In both datasets, we compared the diagnostic performance of the model with that using the MMSE. We estimated optimal cutoff score of our model using receiver operator characteristic analysis.

RESULTS

In total, 595 participants were enrolled, of which 101 of them experienced CD. Our model included both gait speed and temporal gait variability and exhibited good diagnostic performance for classifying CD from normal cognition in both the development (area under the receiver operator characteristic curve [AUC] = 0.788, 95% CI 0.748-0.823, p < 0.001) and validation datasets (AUC = 0.811, 95% CI 0.729-0.877, p < 0.001). Our model showed comparable diagnostic performance for CD with that of the model using the MMSE in both the development (difference in AUC = 0.026, standard error [SE] = 0.043, z statistic = 0.610, p = 0.542) and validation datasets (difference in AUC = 0.070, SE = 0.073, z statistic = 0.956, p = 0.330). The optimal cutoff score of the gait-based model was >-1.56.

DISCUSSION

Our gait-based model using a wearable inertial sensor may be a promising diagnostic marker of CD in older adults.

CLASSIFICATION OF EVIDENCE

This study provides Class III evidence that gait analysis can accurately distinguish older adults with CDs from healthy controls.

Frailty, Cognitive Impairment, and Incident Major Neurocognitive Disorders: Results of the NuAge Cohort Study

BACKGROUND

Frailty is associated with an increased risk of major neurocognitive disorders (MNCD).

OBJECTIVE

This study aims to compare the Fried physical model and the CARE deficit accumulation model for their association with incident major neurocognitive disorders (MNCD), and to examine how the addition of cognitive impairment to these frailty models impacts the incidence in community-dwelling older adults.

METHODS

A subset of community dwellers (n = 1,259) who participated in the "Quebec Longitudinal Study on Nutrition and Successful Aging" (NuAge) were selected in this Elderly population-based observational cohort study with 3 years of follow-up. Fried and CARE frailty stratifications into robust, pre-frail and frail groups were performed using the NuAge baseline assessment. Incident MNCD (i.e., Modified Mini Mental State (3MS) score <  79/100 and Instrumental Activity Daily Living (IADL) score <  6/8) were collected each year over a 3-year follow-up period.

RESULTS

A greater association with incident MNCD of the CARE frail state was observed with an increased predictive value when combined with cognitive impairment in comparison to Fried's one, the highest incidences being observed using the robust state as the reference. Results with the Fried frail state were more heterogenous, with no association with the frail state alone, whereas cognitive impairment alone showed the highest significant incidence.

CONCLUSION

The association of the CARE frail state with cognitive impairment increased the predictive value of MNCD, suggesting that the CARE frailty model may be of clinical interest when screening MCND in the elderly population.

Individual reserve in aging and neurological disease

BACKGROUND AND OBJECTIVE

Cognitive and physical functions correlate and delineate aging and disease trajectories. Whereas cognitive reserve (CR) is well-established, physical reserve (PR) is poorly understood. We, therefore, developed and evaluated a novel and more comprehensive construct, individual reserve (IR), comprised of residual-derived CR and PR in older adults with and without multiple sclerosis (MS). We hypothesized that: (a) CR and PR would be positively correlated; (b) low CR, PR, and IR would be associated with worse study outcomes; (c) associations of brain atrophy with study outcomes would be stronger in lower compared to higher IR due to compensatory mechanisms conferred by the latter.

METHODS

Older adults with MS (n = 66, mean age = 64.48 ± 3.84 years) and controls (n = 66, mean age = 68.20 ± 6.09 years), underwent brain MRI, cognitive assessment, and motoric testing. We regressed the repeatable battery for the assessment of neuropsychological status and short physical performance battery on brain pathology and socio-demographic confounders to derive independent residual CR and PR measures, respectively. We combined CR and PR to define a 4-level IR variable. The oral symbol digit modalities test (SDMT) and timed-25-foot-walk-test (T25FW) served as outcome measures.

RESULTS

CR and PR were positively correlated. Low CR, PR and IR were associated with worse SDMT and T25FW performances. Reduced left thalamic volume, a marker of brain atrophy, was associated with poor SDMT and T25FW performances only in individuals with low IR. The presence of MS moderated associations between IR and T25FW performance.

CONCLUSION

IR is a novel construct comprised of cognitive and physical dimensions representing collective within-person reserve capacities.

The association between cognitive impairment, gait speed, and Walk ratio

Background

Gait speed has been found to be associated with cognitive function. However, gait speed is an unspecific measure that may not be informative about gait patterns. The Walk ratio (step length divided by step frequency) can be measured without specialized equipment, and has been suggested as an indicator of central gait control. However, the association with cognitive function is unknown.

Research question

Is there a relationship between Walk ratio and cognitive function, and gait speed and cognitive function?

Methods

This was a systematic literature review of studies where spatiotemporal gait parameters was reported in populations with cognitive impairment. The search was performed through PubMed, PEDro, AMED, Cochrane, Embase, MEDLINE, and PsycINFO. The studies had to contain either the Walk ratio, or report average step length and average step frequency. In the latter case, the average step length was divided by the average step frequency. The studies also had to report gait speed and the minimal mental state examination (MMSE). Studies testing patients on treadmills or that did not state the exclusion of patients with neurologic or orthopedic diseases, possible affecting gait ability, were excluded.

Results

A total of 24 studies were included, consisting of 909 patients with cognitive impairment and 4,108 healthy controls. The patient group had a lower Walk ratio (mean difference 0.07, p ≤ 0.001) and gait speed (mean difference 0.26, p ≤ 0.001) than the healthy controls. Using linear regression models, we found an association between the MMSE and the Walk ratio (R² = 0.29, p < 0.001) and gait speed (R² = 0.41, p < 0.001) in separate, unadjusted models. In a final model with Walk ratio, gait speed and age, Walk ratio was not significantly associated with MMSE, while gait speed was.

Significance

Our results suggest that preferred gait speed may be preferable to the Walk ratio when assessing older adults with cognitive impairment.

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.

A Deep Learning Model for 3D Ground Reaction Force Estimation Using Shoes with Three Uniaxial Load Cells

Ground reaction force (GRF) is essential for estimating muscle strength and joint torque in inverse dynamic analysis. Typically, it is measured using a force plate. However, force plates have spatial limitations, and studies of gaits involve numerous steps and thus require a large number of force plates, which is disadvantageous. To overcome these challenges, we developed a deep learning model for estimating three-axis GRF utilizing shoes with three uniaxial load cells. GRF data were collected from 81 people as they walked on two force plates while wearing shoes with three load cells. The three-axis GRF was calculated using a seq2seq approach based on long short-term memory (LSTM). To conduct the learning, validation, and testing, random selection was performed based on the subjects. The 60 selected participants were divided as follows: 37 were in the training set, 12 were in the validation set, and 11 were in the test set. The estimated GRF matched the force plate-measured GRF with correlation coefficients of 0.97, 0.96, and 0.90 and root mean square errors of 65.12 N, 15.50 N, and 9.83 N for the vertical, anterior-posterior, and medial-lateral directions, respectively, and there was a mid-stance timing error of 5.61% in the test dataset. A Bland-Altman analysis showed good agreement for the maximum vertical GRF. The proposed shoe with three uniaxial load cells and seq2seq LSTM can be utilized for estimating the 3D GRF in an outdoor environment with level ground and/or for gait research in which the subject takes several steps at their preferred walking speed, and hence can supply crucial data for a basic inverse dynamic analysis.

Association of gait speed with regional brain volumes and risk of dementia in older Japanese: The Hisayama study

BACKGROUND

To investigate the association of gait speed with regional brain volumes and the risk of incident dementia.

METHODS

A total of 1112 dementia-free Japanese residents aged ≥65 years who underwent brain magnetic resonance imaging were followed for 5.0 years (median). The participants were classified into the age- and sex-specific quartile levels of maximum gait speed. Regional gray matter volumes (GMV) and white matter hyperintensities volumes (WMHV) were measured by applying voxel-based morphometry methods. The cross-sectional association of maximum gait speed with regional GMV was examined using an analysis of covariance. We also estimated the association between maximum gait speed level and the risk of developing dementia using a Cox proportional hazards model. Mediation analyses were conducted to determine the contribution of regional brain volumes to the association between maximum gait speed and dementia.

RESULTS

Lower maximum gait speed was significantly associated with lower GMV of the total brain, frontal lobe, temporal lobe, cingulate gyrus, insula, hippocampus, amygdala, basal ganglia, thalamus, and cerebellum, and increased WMHV at baseline. During the follow-up, 108 participants developed dementia. The incidence rate of all dementias increased significantly with decreasing maximum gait speed after adjusting for potential confounders (P for trend = 0.03). The mediating effects of the GMV of the hippocampus, GMV of the insula, and WMHV were significant.

CONCLUSIONS

Lower maximum gait speed was significantly associated with an increased risk of dementia. Reduced GMV of the hippocampus or insula, and an increase in WMHV was likely to be involved in this association.

Relationship between Cognitive Function and Sway of Body in Standing Posture: A Cross-Sectional Study

BACKGROUND

The influence of neurological or balance dysfunction on cognitive impairment has not been well studied. We compared the results of the balance test, measured by either head or foot sway to consider whole body sway, with those of the cognitive impairment test.

METHODS

Individuals of either gender, aged over 60 years, underwent a 30 s balance test. We measured sway while standing on one-leg or two-legs. Sway was evaluated by the distance or area of movement of the head or foot pressure. We also evaluated the effect of visual condition: eyes-open (EO) or -closed (EC). The Mini-Mental State Examination (MMSE) was used to evaluate the degree of cognitive impairment.

RESULTS

The head sway area standing on one leg was significantly correlated to MMSE score with EO (correlation r = -0.462). In standing on two legs, no sway test results showed a significant correlation to MMSE scores with EO. With EC, the magnitude of sway became greater, and was significantly correlated to MMSE scores in the head distance.

CONCLUSION

Although the correlation between head sway and MMSE was not strong, head sway showed a stronger correlation than did foot pressure sway. Standing on one leg, as measured by head sway area, may thus predict cognitive impairment.

Mobility and associations with levels of cerebrospinal fluid amyloid β and tau in a memory clinic cohort

Background

Mobility impairments, in terms of gait and balance, are common in persons with dementia. To explore this relationship further, we examined the associations between mobility and cerebrospinal fluid (CSF) core biomarkers for Alzheimer's disease (AD).

Methods

In this cross-sectional study, we included 64 participants [two with subjective cognitive decline (SCD), 13 with mild cognitive impairment (MCI) and 49 with dementia] from a memory clinic. Mobility was examined using gait speed, Mini-Balance Evaluation Systems test (Mini-BESTest), Timed Up and Go (TUG), and TUG dual-task cost (TUG DTC). The CSF biomarkers included were amyloid-β 42 (Aβ₄₂), total-tau (t-tau), and phospho tau (p-tau₁₈₁). Associations between mobility and biomarkers were analyzed through correlations and multiple linear regression analyses adjusted for (1) age, sex, and comorbidity, and (2) SCD/MCI vs. dementia.

Results

Aβ₄₂ was significantly correlated with each of the mobility outcomes. In the adjusted multiple regression analyses, Aβ₄₂ was significantly associated with Mini-BESTest and TUG in the fully adjusted model and with TUG DTC in step 1 of the adjusted model (adjusting for age, sex, and comorbidity). T-tau was only associated with TUG DTC in step 1 of the adjusted model. P-tau₁₈₁ was not associated with any of the mobility outcomes in any of the analyses.

Conclusion

Better performance on mobility outcomes were associated with higher levels of CSF Aβ₄₂. The association was strongest between Aβ₄₂ and Mini-BESTest, suggesting that dynamic balance might be closely related with AD-specific pathology.

Neural signature of mobility-related everyday function in older adults at-risk of cognitive impairment

Assessment of everyday activities is central to the diagnosis of dementia. Yet, little is known about brain processes associated with everyday functional limitations, particularly during early stages of cognitive decline. Twenty-six older adults (mean = 74.9 y) were stratified by risk using the Montreal Cognitive Assessment battery (MoCA, range: 0- 30) to classify individuals as higher (22-26) and lower risk (27+) of cognitive impairment. We investigated everyday function using a gait task designed to destabilize posture and applied Mobile Brain/Body Imaging. We predicted that participants would increase step width to gain stability, yet the underlying neural signatures would be different for lower versus higher risk individuals. Step width and fronto-parietal activation increased during visually perturbed input. Frontomedial theta increased in higher risk individuals during perturbed and unperturbed inputs. Left sensorimotor beta decreased in lower risk individuals during visually perturbed input. Modulations in theta and beta power were associated with MoCA scores. Our findings suggest that older adults at-risk of cognitive impairment can be characterized by a unique neural signature of everyday function.