Gait speed, cognition and falls in people living with mild-to-moderate Alzheimer disease: data from NILVAD

Associations between white and grey matter damage and gait impairment in cerebral amyloid angiopathy

BACKGROUND

Cerebral amyloid angiopathy (CAA) is associated with white matter damage and neurodegeneration. Gait is impaired in CAA; however, the neural basis of this impairment is unclear.

RESEARCH QUESTION

Are gait impairments in patients with CAA associated with altered cerebral white matter diffusivity and/or atrophy of cortical and subcortical grey matter.

METHODS

Participants with CAA (n=29), Alzheimer's disease (AD; n=16), and normal controls (n=47) were included. Gait was assessed using a 6 m walkway with parameters categorized into rhythm, pace, postural control, and variability domains. The dual-task cost (DTC) of gait speed was calculated for counting backwards, animal fluency, and serial sevens tasks. Whole-brain white matter disruption was quantified using the peak width of skeletonized mean diffusivity (PSMD), and thickness and volume of select cortical, subcortical, and cerebellar regions were quantified using FreeSurfer.

RESULTS

In CAA participants, associations were found between PSMD and pace (standardized parameter estimate (β), 95 % confidence interval (CI): 0.17, 0.03-0.32), and medial orbital frontal cortical thickness and counting backwards DTC (parameter estimate (PE), 95 % CI: -5.7 %/SD, -0.24 to -11.23). Across all groups, including CAA, associations were found between PSMD and pace, variability, counting backwards DTC, and animal fluency DTC; between frontal cortical thickness and pace, counting backwards DTC, and animal fluency DTC; between cortical regions affected by AD (inferior parietal cortex, inferior and middle temporal gyrus) and counting backwards DTC; and between thalamus volume and postural control.

SIGNIFICANCE

Reduced white matter structural integrity and grey matter loss is associated with poor overall gait performance in CAA, AD, and normal controls.

The Importance of Racially and Ethnically Inclusive Gait Speed Reference Values in Individuals 90 Years and Older: LifeAfter90

BACKGROUND AND PURPOSE

Clinicians use reference values to contextualize physical performance scores, but data are sparse in individuals 90 years and older and racial/ethnic diversity is limited in existing studies. Gait speed provides valuable information about an individual's health status. Slow gait speed is associated with falls, cognitive decline, and mortality. Here, we report gait speed reference values in a racially/ethnically diverse oldest-old cohort.

METHODS

LifeAfter90 is a multiethnic cohort study of individuals 90 years and older. Participants are long-term members of an integrated healthcare delivery system without a dementia diagnosis at enrollment. We assessed gait speed using the 4-m walk test and calculated means, standard deviations, and percentiles by age, sex, assistive device use, and device type. We used linear regression to compare means by sex, age, device use and type, living situation and arrangement, and race/ethnicity.

RESULTS AND DISCUSSION

The mean age of the 502 participants was 92.9 (range 90.1-102.8) years. Of these, 62.6% were women, 34.7% were college educated, 90.8% lived in a private residence, 20.9% self-reported as Asian, 22.5% as Black, 11.8% as Hispanic, 35.7% as White, and 9.2% as multiple, "other," or declined to state. The overall mean gait speed was 0.54 m/s (women = 0.51 m/s, men = 0.58 m/s). Mean gait speeds were 0.58 m/s, 0.53 m/s, and 0.48 m/s in the 90 to 91, 92 to 93, and 94+ age categories, respectively. In those without a device, mean gait speed was 0.63 m/s compared to 0.40 m/s in those with a device (cane = 0.44 m/s, walker = 0.37 m/s). Mean gait speed was significantly slower in women compared to men, age category 94+ compared to 90 to 91, participants with a device compared to those without, participants with a walker compared to a cane, and Black participants compared to Asian and White participants. However, differences by race/ethnicity were attenuated when chronic health conditions were considered.

CONCLUSIONS

Reference values developed from this multiethnic 90+ cohort will help clinicians interpret gait speed measures and tailor recommendations toward a 90+ population that is growing in number and in racial/ethnic diversity.

The Ability of Physical Performance Measures to Identify Fall Risk in Older Adults Living With Dementia: A Systematic Review and Meta-Analysis

OBJECTIVES

To determine whether physical performance measures commonly used in clinical settings can discriminate fallers from nonfallers and predict falls in older adults with dementia.

DESIGN

Systematic review and meta-analysis.

SETTING AND PARTICIPANTS

Older adults with dementia residing in the community, hospitals, and residential care facilities.

METHODS

MEDLINE, Embase, PsycINFO, CINAHL, SPORTDiscus, the Cochrane Library, and the PEDro databases were searched from inception until December 27, 2023 (PROSPERO registration number: CRD42022303670). Retrospective or prospective studies that evaluated the associations between physical performance measures and falls in older adults with dementia were included. A random effects model was used to calculate the standardized mean difference (SMD) and 95% CI for each physical performance measure between fallers and nonfallers. Sensitivity analyses were conducted on the longitudinal studies to determine the ability of physical performance measures to predict future falls.

RESULTS

Twenty-eight studies were included in this review (n = 3542). The 5-time chair stand test [SMD = 0.23 (0.01, 0.45)], the Berg Balance Scale [SMD = -0.52 (-0.87, -0.17)], postural sway when standing on the floor [SMD = 0.25 (0.07, 0.43)] and on a foam surface [SMD = 0.45 (0.25, 0.66)], and the Short Physical Performance Battery total score [SMD = -0.46 (-0.66, -0.27)] could discriminate fallers from nonfallers. Sensitivity analyses showed that gait speed could predict future falls in longitudinal cohort studies [SMD = -0.29 (-0.49, -0.08)]. Subgroup analyses showed that gait speed [SMD = -0.21 (-0.38, -0.05)] and the Timed Up and Go test [SMD = 0.54 (0.16, 0.92)] could identify fallers staying in residential care facilities or hospitals.

CONCLUSIONS AND IMPLICATIONS

The 5-time chair stand test, the Berg Balance Scale, postural sway when standing on the floor and a foam surface, and the Short Physical Performance Battery can be used to predict falls in older adults with dementia. Gait speed and the Timed Up and Go test can be used to predict falls in institutionalized older adults with dementia. Clinicians are recommended to use these physical performance measures to assess fall risk in older adults with dementia.

A study on the falls factors among the older adult with cognitive impairment based on large-sample data

Introduction

This study explored the correlative factors of falls among the older adult with cognitive impairment, to provide distinct evidence for preventing falls in the older adult with cognitive impairment compared with the general older adult population.

Methods

This study was based on a cross-sectional survey, with an older adult population of 124,124 was included. The data was sourced from the Elderly Care Unified Needs Assessment for Long-Term Care Insurance in Shanghai. Binary and multivariable logistic regression analyses were conducted sequentially on the correlative factors of falls. Multivariable logistic regression was performed on variables that were significant, stratified by cognitive function levels.

Results

The incidence of fall in the past 90 days was 17.67% in this study. Specific variables such as gender (male), advanced age (≥80), residence with a elevator (or lift), mild or moderate disability, quality of sleep (acceptable/poor) were negatively correlated with falls, while higher education level, living alone, residence with indoor steps, unclean and untidy living environment, MCI or dementia, chronic diseases, restricted joints, impaired vision, and the use of diaper were positively correlative factors of falls. Comparing with older adult with normal cognitive functions, older adult with dementia faced a higher risk of falling due to accessibility barrier in the residence. For general older adults, less frequency of going outside and poor social interactions were positively correlated with falls, while for older adult with cognitive impairments, going outside moderately (sometimes) was found positively correlated with falls. Older adults with cognitive impairments have increased fall risks associated with chronic diseases, restricted joints, and the use of diaper. The risk of falling escalated with the greater number of chronic diseases.

Discussion

For older adult with cognitive impairments, it is advisable to live with others. Additionally, creating an accessible living environment and maintaining the cleanness and tidiness can effectively reduce the risk of falls, particularly for those with MCI or dementia. Optimal outdoor activity plans should be developed separately based on the cognitive function of older adults. Older adult with dementia who have comorbidities should be paid special attention in fall prevention compared to the general older adult population.

Exploring symptom clusters in mild cognitive impairment and dementia with the NIH Toolbox

OBJECTIVE

Symptom clustering research provides a unique opportunity for understanding complex medical conditions. The objective of this study was to apply a variable-centered analytic approach to understand how symptoms may cluster together, within and across domains of functioning in mild cognitive impairment (MCI) and dementia, to better understand these conditions and potential etiological, prevention, and intervention considerations.

METHOD

Cognitive, motor, sensory, emotional, and social measures from the NIH Toolbox were analyzed using exploratory factor analysis (EFA) from a dataset of 165 individuals with a research diagnosis of either amnestic MCI or dementia of the Alzheimer's type.

RESULTS

The six-factor EFA solution described here primarily replicated the intended structure of the NIH Toolbox with a few deviations, notably sensory and motor scores loading onto factors with measures of cognition, emotional, and social health. These findings suggest the presence of cross-domain symptom clusters in these populations. In particular, negative affect, stress, loneliness, and pain formed one unique symptom cluster that bridged the NIH Toolbox domains of physical, social, and emotional health. Olfaction and dexterity formed a second unique cluster with measures of executive functioning, working memory, episodic memory, and processing speed. A third novel cluster was detected for mobility, strength, and vision, which was considered to reflect a physical functioning factor. Somewhat unexpectedly, the hearing test included did not load strongly onto any factor.

CONCLUSION

This research presents a preliminary effort to detect symptom clusters in amnestic MCI and dementia using an existing dataset of outcome measures from the NIH Toolbox.

Evidence of Vestibular and Balance Dysfunction in Patients With Mild Cognitive Impairment and Alzheimer's Disease

OBJECTIVES

Given the expected rise in dementia prevalence, early diagnosis is vital. As a growing body of literature has identified a potential association between vestibular function and cognition, vestibular assessment may aid in early screening. The aim of the study was to better comprehend the proposed association between vestibular function and Alzheimer's disease (AD) by comparing vestibular parameters (vestibular function testing and clinical balance measures) between a group with mild cognitive impairment (MCI), AD, and healthy controls with age-normal cognition.

DESIGN

Cross-sectional analysis of the GECkO study, an ongoing prospective single-center longitudinal cohort study. This study included 100 older adults (55 to 84 years). A total of 33 participants with MCI, 17 participants with AD, and 50 participants of age, sex, and hearing-matched healthy controls were included.

RESULTS

Participants with AD demonstrated a delayed latency of the p13 component measured by cervical vestibular-evoked myogenic potentials (cVEMP) compared with healthy controls and participants with MCI. Other measures including n23 latency, presence of intact responses, rectified amplitude, mean rectified voltage (measured by cVEMP) and lateral vestibulo-ocular reflex gain (measured by video Head Impulse Test [vHIT]) did not differ between groups. The Timed Up and Go (TUG), Performance-Oriented Mobility Assessment-Balance subscale (POMA-B), and Functional Gait Assessment (FGA) differed significantly between the three groups. Here, more cognitively impaired groups were associated with worse clinical balance scores.

CONCLUSIONS

Vestibular and balance deficits were more prevalent in groups with increasing cognitive decline. Regarding vestibular function testing, p13 latency as measured by cVEMP was delayed in participants with AD. Other cVEMP or vHIT measures did not differ between groups. All three clinical balance assessments (TUG, POMA-B, and FGA) resulted in worse scores along the AD continuum. Future research integrating vestibular parameters that add value (including otolith function testing, balance, and spatial navigation) is recommended to validate the association between vestibular function and cognition while avoiding redundant testing.

The longitudinal bidirectional association between sarcopenia and cognitive function in community-dwelling older adults: Findings from the China Health and Retirement Longitudinal Study

Background

Although an association between sarcopenia and cognitive function has been demonstrated, the directional association remains unclear. The present study aimed to evaluate the longitudinal reciprocal relationship and identify the possible temporal sequence between sarcopenia and cognitive function in older Chinese adults.

Methods

Data were collected from the China Health and Retirement Longitudinal Study (CHARLS) baseline survey in 2011 and the follow-up survey in 2015. Cognitive function was measured by episodic memory and executive function. Sarcopenia status (non-sarcopenia, possible sarcopenia and sarcopenia) was defined based on the Asian Working Group for Sarcopenia 2019 criteria. Linear regression analysis and ordinal logistic regression analysis were employed to investigate the relationship between baseline sarcopenia status and follow-up cognition, as well as the association of baseline cognition with follow-up sarcopenia status, respectively. A cross-lagged panel analysis was performed to simultaneously evaluate the bidirectional association and the strength of the temporal relationship.

Results

Of 2689 participants, the median age was 65.0 years and 1249 (46.5%) were female. After adjusting for potential confounders and baseline measurements, baseline sarcopenia status was dose-dependently associated with subsequent cognitive scores (β = -0.45; P for trend = 0.001), and baseline cognitive scores (in tertiles) were also dose-dependently associated with subsequent sarcopenia status (odds ratio (OR) = 0.86; P for trend = 0.017). The cross-lagged panel analysis indicated that the standardised effect size of sarcopenia status on cognitive function (β = -0.09; P < 0.001) is larger relative to the effect of cognitive function on sarcopenia status (β = -0.05; P = 0.019).

Conclusions

There is a longitudinal, bidirectional relationship between sarcopenia status and cognitive function in older Chinese adults. Sarcopenia is likely the driving force in these dynamic associations. These findings imply that interventions in either sarcopenia or cognitive decline may have the ability to generate reciprocal benefits over time. More research is warranted to confirm these findings and to further elucidate underlying causal pathways.

Uneven surface and cognitive dual-task independently affect gait quality in older adults

BACKGROUND

Real-world mobility involves walking in challenging conditions. Assessing gait during simultaneous physical and cognitive challenges provides insights on cognitive health.

RESEARCH QUESTION

How does uneven surface, cognitive task, and their combination affect gait quality and does this gait performance relate to cognitive functioning?

METHODS

Community-dwelling older adults (N = 104, age=75 ± 6 years, 60 % females) performed dual-task walking paradigms (even and uneven surface; with and without alphabeting cognitive task (ABC)) to mimic real-world demands. Gait quality measures [speed(m/s), rhythmicity(steps/minute), stride time variability (%), adaptability (m/s2), similarity, smoothness, power (Hz) and regularity] were calculated from an accelerometer worn on the lower back. Linear-mixed modelling and Tukey analysis were used to analyze independent effects of surface and cognitive task and their interaction on gait quality. Partial Spearman correlations compared gait quality with global cognition and executive function.

RESULTS

No interaction effects between surface and cognitive task were found. Uneven surface reduced gait speed(m/s) (β = -0.07). Adjusted for speed, uneven surface reduced gait smoothness (β = -0.27) and increased regularity (β = 0.09), Tukey p < .05, for even vs uneven and even-ABC vs uneven-ABC. Cognitive task reduced gait speed(m/s) (β = -0.12). Adjusted for speed, cognitive task increased variability (β = 7.60), reduced rhythmicity (β = -6.68) and increased regularity (β = 0.05), Tukey p < .05, for even vs even-ABC and uneven vs uneven-ABC. With demographics as covariates, gait speed was not associated with cognition. Gait quality [lower variability during even-ABC (ρp =-.31) and uneven-ABC (ρp =-.28); greater rhythmicity (ρp between.22 and.29) and greater signal-adaptability AP (ρp between.22 and.26) during all walking tasks] was associated with better global cognition. Gait adaptability during even (ρp =-0.21, p = 0.03) and uneven(ρp =-0.19, p = 0.04) walking was associated with executive function.

SIGNIFICANCE

Surface and cognitive walking tasks independently affected gait quality. Our study with high-functioning older adults suggests that task-related changes in gait quality are related to subtle changes in cognitive functioning.

The Bidirectional Association Between Cognitive Function and Gait Speed in Chinese Older Adults: Longitudinal Observational Study

BACKGROUND

Cognitive and gait speed decline are common conditions in older adults and are often associated with future adverse consequences. Although an association between cognitive function and gait speed has been demonstrated, its temporal sequence remains unclear, especially in older Chinese adults. Clarifying this could help identify interventions to improve public health in older adults.

OBJECTIVE

This study aims to examine the longitudinal reciprocal association between gait speed and cognitive function and the possible temporal sequence of changes in both factors in a national longitudinal cohort.

METHODS

Data were derived from 2 waves (2011 baseline and 2015 follow-up) of the China Health and Retirement Longitudinal Study (CHARLS). Participants 60 years or older, without dementia or Parkinson disease at baseline, and with completed data on gait speed and cognition at both baseline and follow-up were included. Usual gait speed was measured over two 2.5-m walks. Mental intactness and episodic memory were used to assess global cognitive function. Cross-lagged panel models and linear mixed-effects models were used to examine the association between cognition and gait speed over time. Standardized coefficients were reported.

RESULTS

A total of 3009 participants (mean age 66.4 years, SD 5.4 years; 1422/3009, 47.26%, female participants) were eligible for inclusion in our analyses. Cross-lagged panel analyses revealed that after accounting for baseline gait speed, cognition, and potential confounders, baseline global cognition (β=.117, 95% CI 0.082-0.152; P<.001), mental intactness (β=.082, 95% CI 0.047-0.118; P<.001), and episodic memory (β=.102, 95% CI 0.067-0.137; P<.001) were associated with subsequent gait speed. Simultaneously, baseline gait speed was also associated with subsequent global cognition (β=.056, 95% CI 0.024-0.087; P=.001), mental intactness (β=.039, 95% CI 0.008-0.069; P=.01), and episodic memory (β=.057, 95% CI 0.023-0.092; P=.001). The comparison of standardized cross-lagged coefficients suggested that the effect size of baseline global cognition on subsequent gait speed was significantly larger than the reverse effect (χ₁²=6.50, P for difference=.01). However, the effects of both mental intactness and episodic memory on subsequent gait speed were not significantly stronger than those of the reverse pathway (χ₁²=3.33, P for difference=.07 and χ₁²=3.21, P for difference=.07). Linear mixed-effects analyses further supported these bidirectional relationships, revealing that lower baseline cognitive scores predicted steeper declines in gait speed trajectory, and slower baseline gait speed predicted more declines in cognitive trajectory over time.

CONCLUSIONS

There is a longitudinal bidirectional association between usual gait speed and both global cognitive function and specific domains of mental intactness and episodic memory among Chinese older adults. Baseline global cognition is likely to have a stronger association with subsequent gait speed than the reverse pathway. This interlinkage is noteworthy and may have implications for public health. Maintaining normal cognitive function may be an important interventional strategy for mitigating age-related gait speed reduction.

Investigation of the gait parameters after donepezil treatment in patients with alzheimer' s disease

INTRODUCTION

Clinical studies remark that gait disturbance is common in patients with Alzheimer's disease (AD). However, the treatment response of gait disturbance in those patients may constitute a more interesting issue that is rarely addressed.

METHODS

In this prospective, interventional study, we included 14 consecutive patients with a new diagnosis of AD. Basal gait analysis was performed using a 'Gait Analyzer' program that was uploaded to a mobile phone. The gait parameters including Step time (ST), step length (SL), step number (SN), gait velocity (GV), and cadence were measured. Afterward, donepezil 5 mg daily was initiated, and the re-assessments were re-performed 8 weeks after the treatment.

RESULTS

The mean age was 71.78 ± 5.02 (F/M = 8/6). The evaluations after the donepezil treatment showed that there was a significant improvement in the SN (p = 0.021) and SL (p = 0.001) in comparison to the basal evaluations. The repeated analysis in the subgroup of early-stage AD subjects (n = 10) yielded that there were significant improvements in SN (p = 0.003), SL (p = 0.005), and cadence (p = 0.026) after treatment.

CONCLUSIONS

Our results support the efficiency of cholinergic treatment in gait functions in AD subjects.

Exercise modulates APOE expression in brain cortex of female APOE3 and APOE4 targeted replacement mice

Apolipoprotein E (ApoE) is the main cholesterol carrier of the brain and the ε4 gene variant (APOE4) is the most prevalent genetic risk factor for Alzheimer's disease (AD), increasing risk up to 15-fold. Several studies indicate that APOE4 modulates critical factors for neuronal function, including brain-derived neurotrophic factor (BDNF) and peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α). Both proteins show exercise-induced upregulation, which is presumed to mediate many of the beneficial effects of physical activity including improved cognition; however, there is variability in results between individuals potentially in-part due to genetic variations including APOE isoform. This study aimed to determine if the two most prevalent human APOE isoforms influence adaptive responses to exercise-training. Targeted replacement mice, homozygous for either APOE3 or APOE4 were randomized into exercised and sedentary groups. Baseline locomotor function and voluntary wheel-running behavior was reduced in APOE4 mice. Exercised groups were subjected to daily treadmill running for 8 weeks. ApoE protein in brain cortex was significantly increased by exercise in both genotypes. PGC-1α mRNA levels in brain cortex were significantly lower in APOE4 mice, and only tended to increase with exercise in both genotypes. Hippocampal BDNF protein were similar between genotypes and was not significantly modulated by treadmill running. Behavioral and biochemical variations between APOE3 and APOE4 mice likely contribute to the differential risk for neurological and vascular diseases and the exercise-induced increase in ApoE levels suggests an added feature of the potential efficacy of physical activity as a preventative and therapeutic strategy for neurogenerative processes in both genotypes.

Association of diabetes mellitus with gait and falls in community-dwelling older adults: Serial mediation of vision and cognition

BACKGROUND/OBJECTIVE

Diabetes mellitus (DM) is associated with walking performance, but potential underlying mechanisms of this association remain unclear. The present study aims to disentangle the pathways linking DM to gait and falls through the serial mediation effect of vision and cognition among the older population.

METHODS

Data were taken from wave 9 (2018-2019) of the English Longitudinal Study of Aging (ELSA), including 5496 participants aged 60 years and older. DM was identified based on medical diagnosis and laboratory tests. Vision and falls were self-reported. Cognition was evaluated using questionnaire. Gait speed was measured by the "timed walking test". Serial mediation analysis was performed using Mplus 8.3.

RESULTS

DM was associated with impaired gait speed (c = 0.085, P < 0.05) and falls (c = 0.061, P < 0.05). The serial mediation model revealed that vision and cognition significantly mediated the association of DM with impaired gait speed, with 17.97% and 23.60% of the total effects explained by vision and cognition respectively, and 3.37% explained by the path through vision and then cognition. Similarly, vision and cognition significantly mediated the association of DM with falls, with 14.99% and 6.67% of the total effects explained by vision and cognition respectively, and 1.67% explained by the path through vision and then cognition.

CONCLUSIONS

These findings contribute to deeper understanding of the mechanism underlying the association of DM with walking performance. Evaluation and intervention targeted at vision and the cognition may be beneficial for improving gait or reducing falls in older adults with DM.

Reproducibility of isokinetic measures of the knee and ankle muscle strength in community-dwelling older adults without and with Alzheimer's disease

BACKGROUND

To interpret changes of muscle strength in older adults with Alzheimer's disease (AD), determining the reliability of outcome measures is necessary. Therefore, the purpose of the present study was to investigate the relative and absolute intra-rater reliability of concentric isokinetic measures of the knee and ankle muscle strength in community-dwelling older adults without and with AD in the mild and moderate stages.

METHODS

A methodological study was conducted. The participants were submitted to two isokinetic evaluations with an interval of three to seven days. The evaluations consisted of knee extension and flexion at 60°/s (five repetitions) and 180°/s (15 repetitions) and plantar flexion and dorsiflexion of the ankle at 30°/s (five repetitions). The measures of interest were peak torque, average peak torque and total work. The intraclass correlation coefficient two-way mixed model of a single-measure (ICC_3,1), standard error of measurement (SEM) and minimal detectable change at the 95% confidence interval (MDC₉₅) were calculated. The ICC_3,1 was interpreted based on Munro's classification. Standard error of measurement and MDC₉₅ were analyzed in absolute and relative values (percentage of error [SEM%] and change [MDC₉₅%]).

RESULTS

A total of 62 older adults were included and allocated to the three groups: mild-AD (n = 22, 79.9 years, 15 female and seven male), moderate-AD (n = 20, 81.6 years, 15 female and five male) and without-AD (n = 20, 74.3 years, 10 female and seven male). The ICCs_3,1 of the measures of knee were high/very high in the three groups (0.71-0.98). The ICCs_3,1 of the measures of ankle were high/very high in the mild-AD group (0.78-0.92), moderate/high/very high in the moderate-AD group (0.63-0.93) and high/very high in the group without-AD (0.84-0.97). The measurements of knee extensors at 60°/s, knee extensors (peak torque and total work), with the exception of peak torque in the mild-AD group, and flexors (average peak torque) at 180°/s, and ankle dorsiflexors at 30°/s had the lowest of SEM% and MDC95% in the three groups.

CONCLUSION

Concentric isokinetic measures are reliable for the assessment of knee and ankle muscle strength in community-dwelling older adults without and with AD in the mild and moderate stages.

The Role of Sleep Quality and Physical Activity Level on Gait Speed and Brain Hemodynamics Changes in Young Adults-A Dual-Task Study

Walking requires attentional resources, and the studies using neuroimage techniques have grown to understand the interaction between cortical activity and motor performance. Previous studies reported a decline in gait performance and changes in the prefrontal cortex (PFC) activity during a dual-task performance compared to walking only. Some lifestyle factors, such as sleep and physical activity (PA) levels, can compromise walking performance and brain activity. Nonetheless, the studies are scarce. This study aimed to assess gait speed and hemodynamic response in the PFC during a cognitive dual-task (cog-DT) compared to walking only, and to analyze the correlation between PA and sleep quality (SQ) with gait performance and hemodynamic response in the PFC during a single task (ST) and cog-DT performance in young adults. A total of 18 healthy young adults (mean age ± SD = 24.11 ± 4.11 years) participated in this study. They performed a single motor task (mot-ST)—normal walking—and a cog-DT—walking while performing a cognitive task on a smartphone. Gait speed was collected using a motion capture system coupled with two force plates. The hemoglobin differences (Hb-diff), oxyhemoglobin ([oxy-Hb]) and deoxyhemoglobin ([deoxy-Hb]) concentrations in the PFC were obtained using functional near-infrared spectroscopy. The SQ and PA were assessed through the Pittsburg Sleep Quality Index and International Physical Activity Questionnaire-Short Form questionnaires, respectively. The results show a decrease in gait speed (p < 0.05), a decrease in [deoxy-Hb] (p < 0.05), and an increase in Hb-diff (p < 0.05) and [oxy-Hb] (p > 0.05) in the prefrontal cortex during the cog-DT compared to the single task. A positive correlation between SQ and Hb-diff during the cog-DT performance was found. In conclusion, the PFC’s hemodynamic response during the cog-DT suggests that young adults prioritize cognitive tasks over motor performance. SQ only correlates with the Hb-diff during the cog-DT, showing that poor sleep quality was associated with increased Hb-diff in the PFC. The gait performance and hemodynamic response do not correlate with physical activity level.

Six-month change in gait speed to discriminate between those with and without falls history in older people with Mild Cognitive Impairment and mild Alzheimer disease

BACKGROUND AND PURPOSE

The purposes of this study were to identify differences in gait speed performance over 6 months between older people with Preserved Cognition (PrC), with Mild Cognitive Impairment (MCI) and with Alzheimer disease (AD) in mild stage; and to verify if the change in gait speed could discriminate fallers in older people with MCI and AD in a mild stage METHODS: A longitudinal study was conducted with community-dwelling older adults, including 40 with PrC, 36 with MCI and 34 with AD in the mild stage. Gait speed (in m/s) changes were captured through a 10-meter walk test. We documented the number of self-reported falls by monthly calendars that were returned after a 6-month follow-up. During this period, the participants received monthly telephone calls to remind them to fill in the calendar RESULTS: There was a significant difference in terms of sex and age between the groups: 23%, 31% and 19% were female and had a mean age of 72.8, 75.9 and 76.9 years in the PrC, MCI and AD groups respectively. During the follow-up, 45%, 52.7% and 52.9% of the PrC, MCI and AD groups fell. The MCI and AD groups presented lower gait speed compared to the PrC Group at both moments. There was no significant difference in the change of gait speed between groups. In the model adjusted by age, the change in gait speed failed to discriminate fallers in older people with MCI and with AD CONCLUSION: Older people with MCI and AD in the mild stage present lower gait speed compared to older people with PrC. Changes in gait speed over a short period of time do not discriminate fallers in older people with MCI or AD in a mild stage.

Contributions of sex and genotype to exploratory behavior differences in an aged humanized APOE mouse model of late-onset Alzheimer's disease

Age, genetics, and chromosomal sex have been identified as critical risk factors for late-onset Alzheimer's disease (LOAD). The predominant genetic risk factor for LOAD is the apolipoprotein E ε4 allele (APOE4), and the prevalence of LOAD is higher in females. However, the translational validity of APOE4 mouse models for AD-related cognitive impairment remains to be fully determined. The present study investigated the role of both sex and genotype on learning and memory in aged, humanized APOE knock-in mice. Aged (23.27 mo ± 1.21 mo; 39 male/37 female) APOE3/3, APOE3/4, and APOE4/4 mice performed a novel object recognition (NOR) assay. Task-related metrics were analyzed using two-way sex by genotype ANOVAs. Sex differences were more prominent relative to APOE genotype. Prior to NOR, female mice exhibited thigmotaxic center zone avoidance during the open field task relative to males, regardless of genotype. Within object familiarization and NOR tasks, females had greater object interaction and locomotion. Interestingly, only APOE4/4 females on average recognized the novel object. These results suggest that APOE4, although strongly related to LOAD pathogenesis, does not drive cognitive decline in the absence of other risk factors even in very aged mice. Chromosomal sex is a key driver of behavioral phenotypes and thus is a critical variable for translatability of interventions designed to preserve learning and memory in animal models of LOAD. Last, there was a very high degree of variability in behavioral performance across APOE genotypes. A cluster analysis of the behavioral data revealed a low-activity and a high-activity cluster. APOE4 carriers were overrepresented in the low-activity cluster, while male:female distributions did not differ. Collectively, the behavioral data indicate that chromosomal sex has the greatest impact on behavioral phenotype, and APOE4 carrier status may confer greater risk for cognitive decline in some animals.

Impact of Behavioral Assessment and Re-Test as Functional Trainings That Modify Survival, Anxiety and Functional Profile (Physical Endurance and Motor Learning) of Old Male and Female 3xTg-AD Mice and NTg Mice with Normal Aging

Longitudinal approaches for disease-monitoring in old animals face survival and frailty limitations, but also assessment and re-test bias on genotype and sex effects. The present work investigated these effects on 56 variables for behavior, functional profile, and biological status of male and female 3xTg-AD mice and NTg counterparts using two designs: (1) a longitudinal design: naïve 12-month-old mice re-tested four months later; and (2) a cross-sectional design: naïve 16-month-old mice compared to those re-tested. The results confirmed the impact as (1) improvement of survival (NTg rested females), variability of gait (3xTg-AD 16-month-old re-tested and naïve females), physical endurance (3xTg-AD re-tested females), motor learning (3xTg-AD and NTg 16-month-old re-tested females), and geotaxis (3xTg-AD naïve 16-month-old males); but (2) worse anxiety (3xTg-AD 16-month-old re-tested males), HPA axis (3xTg-AD 16-month-old re-tested and naïve females) and sarcopenia (3xTg-AD 16-month-old naïve females). Males showed more functional correlations than females. The functional profile, biological status, and their correlation are discussed as relevant elements for AD-pathology. Therefore, repetition of behavioral batteries could be considered training by itself, with some variables sensitive to genotype, sex, and re-test. In the AD-genotype, females achieved the best performance in physical endurance and motor learning, while males showed a deterioration in most studied variables.

Rehabilitation in Dementia

Dementia is an eurodegenerative disorder, which causes significant disability, especially among the elderly population worldwide. The affected person shows a progressive cognitive decline, which interferes with the independence in performing the activities of daily living. Other than the cognitive domain, the patient tends to have neuropsychiatric, behavioral, sensorimotor, speech, and language-related issues. It is expected that the global burden of the disease will rise with more people entering the geriatric age group. By 2050 close, to 140 million people will be living with one or the other type of dementia. Alzheimer's disease contributes to more than 60% of cases worldwide, followed by vascular dementia. Pharmacotherapy has a limited role to play in the treatment, and at present, no drug is available, which can halt or reverse the progress of the disease. World Health Organization has mandated rehabilitation as a core recommendation in the global action plan on the public health response to dementia. Rehabilitation services are widely recognized as a practical framework to maximize independence and community participation in dementia care. The rehabilitation program is customized to achieve the desired goals, as each person has different experiences, preferences, motivations, strengths, and requirements based on type, course, and severity of the illness. It is an interdisciplinary-team approach with the involvement of several health care professionals. This article reviews the existing literature and outlines the effective rehabilitation strategies concisely in dementia care.

Longitudinal relation between structural network efficiency, cognition, and gait in cerebral small vessel disease

Background

To investigate changes in gait performance over time and how these changes are associated with the decline in structural network efficiency and cognition in older patients with cerebral small vessel disease (SVD).

Methods

In a prospective, single-center cohort with 217 older participants with SVD, we performed 1.5T MRI scans, cognitive tests, and gait assessments evaluated by Timed UP and Go (TUG) test twice over 4 years. We reconstructed the white matter network for each subject based on diffusion tensor imaging tractography, followed by graph-theoretical analyses to compute the global efficiency. Conventional MRI markers for SVD, that is, white matter hyperintensity (WMH) volume, number of lacunes, and microbleeds, were assessed.

Results

Baseline global efficiency was not related to changes in gait performance, while decline in global efficiency over time was significantly associated with gait decline (ie, increase in TUG time), independent of conventional MRI markers for SVD. Neither baseline cognitive performance nor cognitive decline was associated with gait decline.

Conclusions

We found that disruption of the white matter structural network was associated with gait decline over time, while the effect of cognitive decline was not. This suggests that structural network disruption has an important role in explaining the pathophysiology of gait decline in older patients with SVD, independent of cognitive decline.

Associations Between Polypharmacy and Gait Speed According to Cognitive Impairment Status: Cross-Sectional Study in a Japanese Memory Clinic

BACKGROUND

Polypharmacy, usually defined as the use of 5 or more drugs, is associated with reduced quality of life, adverse events, and frailty. Slow gait speed is a component of physical frailty, and some studies have suggested an association between polypharmacy and slow gait speed.

OBJECTIVE

We aimed to determine the effects of polypharmacy on the gait difference according to stages of cognitive decline in a cross-sectional study of memory clinic patients.

METHODS

Participants were 431 outpatients aged 65 year or older who were cognitively normal (CN) or had mild cognitive impairment (MCI) or dementia due to Alzheimer's disease. Participants were divided into a polypharmacy group and a non-polypharmacy group in each group. Multiple regression analysis and logistic analysis were used for data analysis.

RESULTS

There were 182 patients in the polypharmacy group and 249 patients in the non-polypharmacy group. Multiple regression analysis revealed that gait speed had significant negative associations with number of medications and polypharmacy status in the CN group (β: -0.026 [-0.041 to -0.0018] and -0.128 [-0.022 to -0.0033], respectively) and MCI group (-0.018 [-0.028 to -0.0009] and -0.100 [-0.166 to -0.0034]). Logistic regression analysis also showed that number of medications was associated with slow gait status (< 1 m/s) in the CN group (OR: 1.336 [1.115 to 1.601]) and MCI group (1.128 [1.022 to 1.244]).

CONCLUSION

CN and MCI patients with polypharmacy have slower gait speed. Attention should be paid to decreased gait speed in older adults with polypharmacy even when their cognitive function is relatively preserved.

Feasibility of improving strength and functioning and decreasing the risk of falls in older adults with Alzheimer's dementia: a randomized controlled home-based exercise trial

PURPOSE

To determine the effects of a Home-based multimodal exercise program for older people with Alzheimer's disease (AD-HOMEX) on muscle strength, mobility, the risk of falls and functioning.

MATERIALS AND METHODS

A trial with a blinded assessor was conducted involving 40 older people with mild to moderate AD randomized to an intervention group (IG) or control group (CG). The IG participated in a 16-week protocol with three 60-minute sessions per week. The sessions were performed at the participant's home by a physiotherapist and involved progressive individualized physical exercises. Muscle strength (5X Sit-to-Stand Test [5XSTS], 30-Second Chair Stand test, isokinetic and hand-grip dynamometer), functioning (DAFS-R and ADL-Q), mobility and the risk of falls (TUG) were assessed at baseline and after training. Intention-to-treat analysis was adopted.

RESULTS

There was a significant group-evaluation time interaction for the 5XSTS (p = 0.011). The IG demonstrated an improved performance on the 5XSTS (p = 0.020) and a reduced risk of falls (p = 0.000), whereas the CG exhibited a worse functional limitation (p = 0.008) after 16 weeks. The CG had an increased risk of falls (p = 0.006) and worse performance on the ADL-Q (p = 0.047) at the follow-up evaluation. An improvement in the IG and worsening in the CG were found regarding transition patterns between severity levels of functional limitation based on the ADL-Q.

CONCLUSIONS

Home-based physical exercise for older people with mild to moderate AD is an effective strategy that decreases the risk of falls and improves strength and functioning.

The efficacy of exergaming in people with major neurocognitive disorder residing in long-term care facilities: a pilot randomized controlled trial

BACKGROUND

It is currently unknown whether exergaming is efficacious in people with major neurocognitive disorder (MNCD) residing in long-term care facilities. This pilot randomized controlled trial (RCT) explored the efficacy of a stepping exergame program on gait speed, balance, mobility, reaction time, cognitive and neuropsychiatric outcomes, quality of life, and daily life functioning in people with MNCD residing in long-term care facilities.

METHODS

Participants were randomly assigned to 8 weeks, three times weekly, 15 min of exergaming versus watching preferred music videos. The exergame device consisted of a pressure-sensitive step training platform on which participants performed stepping movements to play the games. The device automatically adapted the training level to the participants' capabilities. The Short Physical Performance Battery (SPPB), step reaction time test (SRTT), Montréal Cognitive Assessment (MoCA), Neuropsychiatric Inventory (NPI), Cornell Scale for Depression in Dementia (CSDD), Dementia Quality of Life (DQoL), and Katz Activities of Daily Living (Katz ADL) were assessed at baseline and post-intervention. A Quade's non-parametric ANCOVA controlling for baseline values with post hoc Bonferroni correction (p < 0.00625) was used to analyze pre- and post-differences between the groups. Partial eta-squared (η²p) effect sizes were calculated.

RESULTS

Forty-five of 55 randomized inpatients with mild to moderate MNCD (Mini-Mental State Examination score = 17.2 ± 4.5; aged 70-91; 35 women) completed the study. The exergame group (n = 23) demonstrated improvements in gait speed (p < 0.001, η²_p = 0.41), total SPPB (p < 0.001, η²_p = 0.64), SRTT (p<0.001, η²_p = 0.51), MoCA (p<0.001, η²_p = 0.38), and reductions in CSDD (p<0.001, η²_p = 0.43) compared to the control group (n = 22). There were no differences in NPI (p = 0.165, η²_p = 0.05), DQoL (p = 0.012, η²_p = 0.16), and ADL (p = 0.008, η²_p = 0.16) post-intervention scores between the experimental and control group, albeit DQol and ADL measures showed large effect sizes in the exergame group. The mean attendance rate was 82.9% in the exergame group and 73.7% in the music control group. There were no study-related adverse events reported by the participants, nor observed by the research team.

CONCLUSIONS

The findings of this pilot RCT suggest that an individually adapted exergame training improves lower extremity functioning, cognitive functioning and step reaction time and symptoms of depression in inpatients with MNCD residing in long-term care facilities.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT04436302.

Prevalence of Falls and Fractures in Alzheimer's Patients Compared to General Population

Introduction Alzheimer's disease (AD), found in the aging elderly population, is a progressive neurodegenerative disorder that leads to worsening memory loss and cognitive impairment. Falls and fractures are common in the overall elderly population. Hence, the purpose of this study is to determine the prevalence of falls and fractures in Alzheimer's patients compared to the general population. Methodology This longitudinal study was conducted at the neurology outpatient department (OPD) in a tertiary healthcare setup in Pakistan from November 2019 till April 2020. Previously confirmed diagnosed Alzheimer's patients from neurology OPD were included in one group. Equal number of gender and age-matched healthy participants were included in the reference group. Participants were followed for 12 months to determine the incidence of falls and non-vertebral fractures. Results The incidence of fall was significant in the Alzheimer group compared to the reference group (22.8% vs. 10.9%; relative risk (RR): 2.08; P-value: 0.01). Fractures were also significantly more common in the Alzheimer group compared to the reference group (12.8% vs. 5.1%; RR: 2.51; P-value: 0.03). Conclusion This study demonstrated a higher incidence of falls and fractures in Alzheimer's patients compared to healthy non-Alzheimer individuals. Management of AD should include measures to reduce falls and fractures in addition to standard therapy.

Decreased nesting behavior, selective increases in locomotor activity in a novel environment, and paradoxically increased open arm exploration in Neurogranin knockout mice

Aims

Neurogranin (NRGN) is a postsynaptic protein kinase substrate that binds calmodulin in the absence of calcium. Recent studies suggest that NRGN is involved in neuropsychiatric disorders, including schizophrenia, ADHD, and Alzheimer's disease. Previous behavioral studies of Nrgn knockout (Nrgn KO) mice identified hyperactivity, deficits in spatial learning, impaired sociability, and decreased prepulse inhibition, which suggest that these mice recapitulate some symptoms of neuropsychiatric disorders. To further validate Nrgn KO mice as a model of neuropsychiatric disorders, we assessed multiple domains of behavioral phenotypes in Nrgn KO mice using a comprehensive behavioral test battery including tests of homecage locomotor activity and nesting behavior.

Methods

Adult Nrgn KO mice (28‐54 weeks old) were subjected to a battery of comprehensive behavioral tests, which examined general health, nesting behavior, neurological characteristics, motor function, pain sensitivity, locomotor activity, anxiety‐like behavior, social behavior, sensorimotor gating, depression‐like behavior, and working memory.

Results

The Nrgn KO mice displayed a pronounced decrease in nesting behavior, impaired motor function, and elevated pain sensitivity. While the Nrgn KO mice showed increased locomotor activity in the open field test, these mice did not show hyperactivity in a familiar environment as measured in the homecage locomotor activity test. The Nrgn KO mice exhibited a decreased number of transitions in the light‐dark transition test and decreased stay time in the center of the open field test, which is consistent with previous reports of increased anxiety‐like behavior. Interestingly, however, these mice stayed on open arms significantly longer than wild‐type mice in the elevated plus maze. Consistent with previous studies, the mutant mice exhibited decreased prepulse inhibition, impaired working memory, and decreased sociability.

Conclusions

In the current study, we identified behavioral phenotypes of Nrgn KO mice that mimic some of the typical symptoms of neuropsychiatric diseases, including impaired executive function, motor dysfunction, and altered anxiety. Most behavioral phenotypes that had been previously identified, such as hyperlocomotor activity, impaired sociability, tendency for working memory deficiency, and altered sensorimotor gating, were reproduced in the present study. Collectively, the behavioral phenotypes of Nrgn KO mice detected in the present study indicate that Nrgn KO mice are a valuable animal model that recapitulates a variety of symptoms of neuropsychiatric disorders, such as schizophrenia, ADHD, and Alzheimer's disease.

We found that Neurogranin knockout mice exhibit decreased nesting behavior, selective increases in locomotor activity in a novel environment, and paradoxically increased open arm exploration. Considering the behavioral phenotypes that had been previously identified, we propose that Neurogranin KO mice are a valuable animal model that recapitulates a variety of symptoms of neuropsychiatric disorders, such as schizophrenia, ADHD, and Alzheimer's disease.

Antidepressant use and orthostatic hypotension in older adults living with mild-to-moderate Alzheimer disease

OBJECTIVES

Antidepressant use is often reported as a risk factor for Orthostatic Hypotension (OH), however this relationship has never been explored in those with mild/moderate Alzheimer Disease (AD), who may represent a particularly vulnerable cohort.

METHODS

We performed a cross-sectional analysis of baseline data from the NILVAD study. Participants with mild-moderate AD were recruited from 23 centres in nine countries. Systolic and Diastolic Blood Pressure (SBP/DBP) was recorded in the seated position and after both 1 and 5 minutes of standing. OH was defined as a drop of ≥20 mmHg SBP/≥10 mmHg DBP. We examined the relationship between antidepressant use, orthostatic BP drop and the presence of OH, controlling for important covariates.

RESULTS

Of 509 participants (72.9 ± 8.3 years, 61.9% female), two-fifths (39.1%; 199/509) were prescribed a regular antidepressant. Antidepressant use was associated with a significantly greater SBP and DBP drop at 5 minutes (β: 1.83, 0.16-3.50, P = .03 for SBP; β: 1.13, 0.02-2.25, P < .05 for DBP). Selective Serotonin Reuptake Inhibitor (SSRI) use was associated with a significantly greater likelihood of OH (OR 2.0, 1.1-3.6, P = .02). Both findings persisted following robust covariate adjustment.

CONCLUSIONS

In older adults with AD, antidepressants were associated with a significantly greater SBP/DBP drop at 5 minutes. SSRI use in particular may be a risk factor for OH. This emphasises the need to screen older antidepressant users, and particularly those with AD, for ongoing orthostatic symptoms in order to reduce the risk of falls in this vulnerable cohort.

The Importance of Exercise in Alzheimer's Disease and the Minds in Motion® Program: An Editorial

Alzheimer's Disease (AD) and other dementias are prevalent neurodegenerative diseases characterized by decreased cognition, physical function, and quality of life. Currently, millions of people are living with AD and other dementias. With no cure, research has examined the use of non-pharmacological treatment options including exercise. Many high-quality studies demonstrate that physical activity slows the progression of AD's many outcomes, and is beneficial to overall quality of life in those living with AD. However, creating exercise interventions at the community level that individuals will adhere to is often a challenge. The Alzheimer's Society of Canada developed a unique program that combines physical activity with cognitive stimulation in a social atmosphere: The Minds in Motion® program. Minds in Motion® addresses many of the barriers often linked to poor physical activity participation in chronic diseases (such as inclusion of the care partner), to ensure the best program uptake. The Minds in Motion® program has anecdotally been successful in helping to increase physical function and social skills in those living with dementia. However, it is important to connect community-driven programs with the academic research community, to create an opportunity for high quality evaluation metrics that can be disseminated at multiple levels: to research audiences, clinical audiences, and to those in the community. With ongoing collaborations between research and community programs, there is a greater opportunity to understand the positive impact of a program, which ultimately increases the chance of funding for the program. In this editorial, we highlight that community-integrated research is an important priority for future collaborations.