Susan Muir-Hunter

Motoric cognitive risk syndrome Multicountry prevalence and dementia risk

Objectives: Our objective is to report prevalence of motoric cognitive risk syndrome (MCR), a newly described predementia syndrome characterized by slow gait and cognitive complaints, in multiple countries, and its association with dementia risk. Methods: Pooled MCR prevalence analysis of individual data from 26,802 adults without dementia and disability aged 60 years and older from 22 cohorts from 17 countries. We also examined risk of incident cognitive impairment (Mini-Mental State Examination decline ≥4 points) and dementia associated with MCR in 4,812 individuals without dementia with baseline Mini-Mental State Examination scores ≥25 from 4 prospective cohort studies using Cox models adjusted for potential confounders. Results: At baseline, 2,808 of the 26,802 participants met MCR criteria. Pooled MCR prevalence was 9.7% (95% confidence interval [CI] 8.2%–11.2%). MCR prevalence was higher with older age but there were no sex differences. MCR predicted risk of developing incident cognitive impairment in the pooled sample (adjusted hazard ratio [aHR] 2.0, 95% CI 1.7–2.4); aHRs were 1.5 to 2.7 in the individual cohorts. MCR also predicted dementia in the pooled sample (aHR 1.9, 95% CI 1.5–2.3). The results persisted even after excluding participants with possible cognitive impairment, accounting for early dementia, and diagnostic overlap with other predementia syndromes. Conclusion: MCR is common in older adults, and is a strong and early risk factor for cognitive decline. This clinical approach can be easily applied to identify high-risk seniors in a wide variety of settings.

The Motor Signature of Mild Cognitive Impairment: Results From the Gait and Brain Study

Background. Early motor changes associated with aging predict cognitive decline, which suggests that a “motor signature” can be detected in predementia states. In line with previous research, we aim to demonstrate that individuals with mild cognitive impairment (MCI) have a distinct motor signature, and specifically, that dual-task gait can be a tool to distinguish amnestic (a-MCI) from nonamnestic MCI. Methods. Older adults with MCI and controls from the “Gait and Brain Study” were assessed with neurocognitive tests to assess cognitive performance and with an electronic gait mat to record temporal and spatial gait parameters. Mean gait velocity and stride time variability were evaluated under simple and three separate dual-task conditions. The relationship between cognitive groups (a-MCI vs nonamnestic MCI) and gait parameters was evaluated with linear regression models and adjusted for confounders. Results. Ninety-nine older participants, 64 MCI (mean age 76.3±7.1 years; 50% female), and 35 controls (mean age 70.4±3.9 years; 82.9% female) were included. Forty-two participants were a-MCI and 22 were nonamnestic MCI. Multivariable linear regression (adjusted for age, sex, physical activity level, comorbidities, and executive function) showed that a-MCI was significantly associated with slower gait and higher dual-task cost under dual-task conditions. Conclusion. Participants with a-MCI, specifically with episodic memory impairment, had poor gait performance, particularly under dual tasking. Our findings suggest that dual-task assessment can help to differentiate MCI subtyping, revealing a motor signature in MCI.

Association of Dual-Task Gait With Incident Dementia in Mild Cognitive Impairment: Results From the Gait and Brain Study

Importance Gait performance is affected by neurodegeneration in aging and has the potential to be used as a clinical marker for progression from mild cognitive impairment (MCI) to dementia. A dual-task gait test evaluating the cognitive-motor interface may predict dementia progression in older adults with MCI. Objective To determine whether a dual-task gait test is associated with incident dementia in MCI. Design, Setting, and Participants The Gait and Brain Study is an ongoing prospective cohort study of community-dwelling older adults that enrolled 112 older adults with MCI. Participants were followed up for 6 years, with biannual visits including neurologic, cognitive, and gait assessments. Data were collected from July 2007 to March 2016. Main Outcomes and Measures Incident all-cause dementia was the main outcome measure, and single- and dual-task gait velocity and dual-task gait costs were the independent variables. A neuropsychological test battery was used to assess cognition. Gait velocity was recorded under single-task and 3 separate dual-task conditions using an electronic walkway. Dual-task gait cost was defined as the percentage change between single- and dual-task gait velocities: ([single-task gait velocity – dual-task gait velocity]/ single-task gait velocity) × 100. Cox proportional hazard models were used to estimate the association between risk of progression to dementia and the independent variables, adjusted for age, sex, education, comorbidities, and cognition. Results Among 112 study participants with MCI, mean (SD) age was 76.6 (6.9) years, 55 were women (49.1%), and 27 progressed to dementia (24.1%), with an incidence rate of 121 per 1000 person-years. Slow single-task gait velocity (<0.8 m/second) was not associated with progression to dementia (hazard ratio [HR], 3.41; 95% CI, 0.99-11.71; P = .05) while high dual-task gait cost while counting backward (HR, 3.79; 95% CI, 1.57-9.15; P = .003) and naming animals (HR, 2.41; 95% CI, 1.04-5.59; P = .04) were associated with dementia progression (incidence rate, 155 per 1000 person-years). The models remained robust after adjusting by baseline cognition except for dual-task gait cost when dichotomized. Conclusions and Relevance Dual-task gait is associated with progression to dementia in patients with MCI. Dual-task gait testing is easy to administer and may be used by clinicians to decide further biomarker testing, preventive strategies, and follow-up planning in patients with MCI. Trial Registration clinicaltrials.gov: NCT03020381.

Donepezil Improves Gait Performance in Older Adults with Mild Alzheimer's Disease: A Phase II Clinical Trial

BACKGROUND Gait deficits are prevalent in people with dementia and increase their fall risk and future disability. Few treatments exist for gait impairment in Alzheimers disease (AD) but preliminary studies have shown that cognitive enhancers may improve gait in this population. OBJECTIVE To determine the efficacy of donepezil, a cognitive enhancer that improves cholinergic activity, on gait in older adults newly diagnosed with AD. METHODS Phase II clinical trial in 43 seniors with mild AD who received donepezil. Participants had not previously received treatment with cognitive enhancers. Primary outcome variables were gait velocity (GV) and stride time variability (STV) under single and dual-task conditions measured using an electronic walkway. Secondary outcomes included attention and executive function. RESULTS After four months of treatment, participants with mild AD improved their GV from 108.4 ± 18.6 to 113.3 ± 19.5 cm/s, p = 0.010; dual-task GV from 80.6 ± 23.0 to 85.3 ± 22.3 cm/s, p = 0.028. Changes in STV were in the expected direction although not statistically significant. Participants also showed improvements in Trail Making Tests A (p = 0.030), B (p = 0.001), and B-A (p = 0.042). CONCLUSION Donepezil improved gait in participants with mild AD. The enhancement of dual-task gait suggests the positive changes achieved in executive function as a possible causal mechanism. This study yielded a clinically significant estimate of effect size; as well, the findings are relevant to the feasibility and ethics considerations for the design of a Phase III clinical trial.

Gait cost of using a mobility aid in older adults with Alzheimer's disease

malist shoes and to barefoot walking in general could explain the greater variance in gait variables during this condition. In summary, it may not be advisable for older adults to change abruptly from standard stable shoes to minimalist shoes or barefoot in everyday life because they reduce balance control and cause acute alterations in gait patterns. Nevertheless, the regular use of minimalist shoes may also improve balance control and walking ability over time. In a protected environment, these shoes could be a cheap and easy way to exercise balance control and reduce long-term fall risk. Further studies are necessary to confirm this hypothesis.

Serum Parathyroid Hormone but Not Vitamin D Is Associated with Impaired Gait in Community-Dwelling Older Adults

AG043548–04 to MDN. Author Contributions: Neuman M.D.: obtaining funding; study concept and design; acquisition, analysis, and interpretation of data; writing first draft of manuscript; critical revision of manuscript; final approval of submitted manuscript. Mehta S.: study concept and design, analysis and interpretation of data, critical revision of manuscript, final approval of submitted manuscript. Bannister E.R.: acquisition, analysis, and interpretation of data; critical revision of manuscript; final approval of submitted manuscript. Hesketh P.J.: acquisition and analysis of data, critical revision of manuscript, final approval of submitted manuscript. Horan A.D. and Elkassabany N.M.: study concept and design, interpretation of data, critical revision of manuscript, final approval of submitted manuscript. Sponsor’s Role: The study sponsor had no role in the design, methods, subject recruitment, data collections, analysis, or preparation of the paper.

Defining rehabilitation success in older adults with dementia–results from an inpatient geriatric rehabilitation unit

ObjectiveTo quantify the magnitude of functional recovery in older adults with and without dementia admitted to an inpatient geriatric rehabilitation program by measuring change in measures of global physical function and physical therapy treatment outcomes.DesignRetrospective cohort study.SettingRehabilitation academic hospital.ParticipantsConsecutive subjects, with (N=65, age 81.9±6.0 y) and without (N=157, age 82.8±7.2 y) a dementia diagnosis, had assessment data at admission and discharge from inpatient geriatric rehabilitation unit.InterventionsNot applicable.MeasurementsThe Functional Independence Measure (FIM) was used to estimate level of independence on activities of daily living. The Berg Balance Scale (BBS), Timed Up & Go Test (TUG) and 2 Minute Walk Test (2MWT) were used to estimate functional mobility and endurance. The FIM (total, motor subscale, cognitive subscale scores) were used to calculate rehabilitation efficacy and efficiency scores.ResultsAfter controlling for confounding, there was no group difference for gains on the BBS, TUG, 2MWT; there was no group difference on rehabilitation efficacy and efficiency values based on the FIM motor subscale. The magnitude of the rehabilitation gain using the total FIM score was statistically different between groups, people with dementia having smaller gains.ConclusionOlder adults with a diagnosis of dementia are capable of making motor function recovery during inpatient sub-acute rehabilitation comparable to their peers without a dementia diagnosis. The metric used to evaluate functional recovery influences the determination of rehabilitation success between groups. Rehabilitation success should be defined among people with a dementia diagnosis by a change in the motor subscale of the FIM, rather than the total FIM score or the gain relative to the maximal FIM score.

Motor and Cognitive Trajectories Before Dementia: Results from Gait and Brain Study: Motor and Cognitive Trajectories Before Dementia

To compare the trajectories of motor and cognitive decline in older adults who progress to dementia with the trajectories of those who do not. To evaluate the added value of measuring motor and cognitive decline longitudinally versus cross‐sectionally for predicting dementia.

Consensus on Shared Measures of Mobility and Cognition: From the Canadian Consortium on Neurodegeneration in Aging (CCNA)

Abstract Background A new paradigm is emerging in which mobility and cognitive impairments, previously studied, diagnosed, and managed separately in older adults, are in fact regulated by shared brain resources. Deterioration in these shared brain mechanisms by normal aging and neurodegeneration increases the risk of developing dementia, falls, and fractures. This new paradigm requires an integrated approach to measuring both domains. We aim to identify a complementary battery of existing tests of mobility and cognition in community-dwelling older adults that enable assessment of motor-cognitive interactions. Methods Experts on mobility and cognition in aging participated in a semistructured consensus based on the Delphi process. After performing a scoping review to select candidate tests, multiple rounds of consultations provided structured feedback on tests that captured shared characteristics of mobility and cognition. These tests needed to be sensitive to changes in both mobility and cognition, applicable across research studies and clinics, sensitive to interventions, feasible to perform in older adults, been previously validated, and have minimal ceiling/floor effects. Results From 17 tests appraised, 10 tests fulfilled prespecified criteria and were selected as part of the “Core-battery” of tests. The expert panel also recommended a “Minimum-battery” of tests that included gait speed, dual-task gait speed, the Montreal Cognitive Assessment and Trail Making Test A&B. Conclusions A standardized assessment battery that captures shared characteristics of mobility and cognition seen in aging and neurodegeneration may increase comparability across research studies, detection of subtle or common reversible factors, and accelerate research progress in dementia, falls, and aging-related disabilities.

Do depressive symptoms affect balance in older adults with mild cognitive impairment? Results from the “gait and brain study”

ABSTRACT Background: Mild cognitive impairment (MCI) and depression independently affect balance control in older adults. However, it is uncertain whether depressive symptoms would amplify balance problems in older adults with MCI. Aim: To evaluate if the presence of significant depressive symptoms affects postural sway under somatosensory challenges in a MCI population. Methods: Eighty two participants (mean of 75.3±6.4years of age; 46% women) with MCI completed cognitive and balance assessments. Participants were grouped by severity of depressive symptoms using the Geriatric Depression Scale‐15, as MCI with depressive symptoms (MCI‐D=14, score≥5) and MCI without depressive symptoms (MCI=68, score<5). Postural sway area was evaluated during eyes open (EO) and eyes closed (EC) while standing on a rigid flat force plate platform, and compared across groups. Analyses were controlled for age, sex, comorbidities, anti‐depressant medication use, executive function, and baseline sway. Results: MCI‐D showed larger postural sway area when compared with MCI irrespective of visual feedback conditions (p=0.03). This difference remained significant after adjusting for anti‐depressant use and executive function performance. The lack of interaction between groups and visual condition was associated with group differences in postural sway during EO condition (Beta=0.08, CI −257.5–621.9; p=0.41) and by comparable sway increase from EO to EC in both groups. Conclusion: Depressive symptoms in individuals with MCI worsened postural stability during both eyes open and eyes closed conditions independently of cognitive function. Significant depressive symptoms may affect balance in MCI populations, potentially increasing the risk of falls. HIGHLIGHTSMCI and depression are independently associated with falls.Depressive symptoms may amplify balance problems in MCI during sensorimotor challenges.In MCI populations depressive symptoms impair balance independently of cognitive function.Affective dysfunction in MCI may increase the risk of falls.