Vascular burden as a substrate for higher-level gait disorders in older adults. A review of brain mapping literature

Vascular brain burden, evaluated as white matter hyperintensities (WMH), may explain in part the higher-level gait disorders found in older adults. However, the magnitude and location of WMH as a determinant of higher-level gait disorders remain unknown. The purpose of this review was to determine if the magnitude and distribution of WMH would be associated with the presence of gait disorders in older adults. Medline was searched using the following keywords: "gait", "gait disorders, neurologic", "walking", "cerebrovascular disorders", "leukoaraiosis", "leukoencephalopathies" and "aged". Additional references were reviewed from the bibliographies, and from citation searches on key articles. Observational studies, without language restriction, published between 1995-2011 and exploring simultaneously WMH on MRI and gait performance were selected. Twenty-one studies met the selection criteria. The number of participants per study ranged from 14 to 3301 (35% to 75% female). The total WMH burden was associated with gait disorders in all studies. The largest WMH fractions associated with gait disorders were found in the frontal lobe, the centrum semiovale, the posterior limb of internal capsule, the genu and the splenium of corpus callosum. Gait velocity, stride length and step width were the gait parameters most commonly affected in the presence of WMH. The brain mapping literature supports the hypothesis that a high WMH burden is associated with gait disorders in the course of aging. This could give rise to new strategies for the prevention of higher-level gait disorders and falls in the elderly based on the management of cerebrovascular disease

The Attentional Demands of Ambulating with an Assistive Device in Older Adults with Alzheimer\u27s Disease

Ambulation with a mobility aid is a unique real-life situation of multi-tasking. These simultaneous motor tasks place increased demands on executive function in healthy young and older adults, but the demands have not been evaluated in people with Alzheimer\u27s disease (AD). Mobility problems are common among adults with AD, leading to provision of a mobility aid to optimize independent activity. The study objectives were: (i) to determine the dual-task cost (DTC) associated with the use of a mobility aid in straight and complex path walking, and (ii) to evaluate the association between executive function and ambulation with a mobility aid in older adults with AD and age-sex matched cognitively normal controls. Fourteen people (mean age±SD, 72.6±9.9years) with a diagnosis of probable AD (MMSE range 12-25) and controls (mean age±SD, 72.9±9.5) walked at a self-selected pace and using a 4-wheeled walker in a 6m straight path and a Figure of 8 Test. Ambulation with the walker in a straight path produced a low DTC that was not different between the groups. Ambulation with the 4-wheeled walker in the complex path produced a significantly different DTC in the group with AD at -38.1±23.5% compared to -19.7±21.4% (p=0.041). Lower scores on executive function were associated with longer times across test conditions. Ambulation with a 4-wheeled walker, in particular maneuvering around obstacles, requires greater attentional costs in dementia. Future research should explore the timing for safely introducing mobility aids in AD and the role of improving executive function

White matter integrity is associated with gait impairment and falls in mild cognitive impairment. Results from the gait and brain study

© 2019 The Authors Background: Mild Cognitive Impairment (MCI) is an intermediate state between normal cognition and dementia that is associated with twice the risk of falls. It is unknown whether white matter integrity (WMI) is associated with increased risk of falls in MCI. The purpose of this study was to evaluate if early changes in WMI were associated with gait impairment and falls. Methods: Forty-three participants with MCI from the Gait and Brain Study underwent standardized assessment of cognition, gait performance under single and dual-task conditions (walking while talking), and WMI using 3 Tesla diffusion tensor imaging (DTI). Macro-structural imaging characteristics (white and grey matter morphology) as well as microstructural WMI parameters were examined for associations with falls and gait performance. Significantly associated WM tracts were then used to test the interplay between WMI and history of falls, after adjusting for other important covariates. Results: Multiple WM tracts (corpus callosum, forceps minor, and the left inferior fronto-occipital fasciculus) were significantly associated with history of falls and lower dual-task gait performance. A multivariable regression model showed that fall history was associated with the radial diffusivity in the forceps minor, even after adjusting for education, sex, BMI, MMSE scores, comorbidities, gait velocity and WMH volume as covariates. Conclusions: Multiple WM tracts that are known to be involved in executive and visuospatial functions were preferentially affected in MCI individuals with history of falls. Our preliminary findings support the notion that WMI in key brain regions may increase risk of falls in older adults with MCI

Nutrient Biomarker Patterns, Cognitive Function, and Mri Measures of Brain Aging

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Gait and Cognition: A Complementary Approach to Understanding Brain Function and the Risk of Falling

Until recently, clinicians and researchers have performed gait assessments and cognitive assessments separately when evaluating older adults, but increasing evidence from clinical practice, epidemiological studies, and clinical trials shows that gait and cognition are interrelated in older adults. Quantifiable alterations in gait in older adults are associated with falls, dementia, and disability. At the same time, emerging evidence indicates that early disturbances in cognitive processes such as attention, executive function, and working memory are associated with slower gait and gait instability during single- and dual-task testing and that these cognitive disturbances assist in the prediction of future mobility loss, falls, and progression to dementia. This article reviews the importance of the interrelationship between gait and cognition in aging and presents evidence that gait assessments can provide a window into the understanding of cognitive function and dysfunction and fall risk in older people in clinical practice. To this end, the benefits of dual-task gait assessments (e.g., walking while performing an attention-demanding task) as a marker of fall risk are summarized. A potential complementary approach for reducing the risk of falls by improving certain aspects of cognition through nonpharmacological and pharmacological treatments is also presented. Untangling the relationship between early gait disturbances and early cognitive changes may be helpful in identifying older adults at risk of experiencing mobility decline, falls, and progression to dementia. J Am Geriatr Soc 60: 2127-2136, 2012

Spatio-temporal gait analysis based on human-smart rollator interaction

The ability to walk is typically related to several biomechanical components that are involved in the gait cycle (or stride), including free mobility of joints, particularly in the legs; coordination of muscle activity in terms of timing and intensity; and normal sensory input, such as vision and vestibular system. As people age, they tend to slow their gait speed, and their balance is also affected. Also, the retirement from the working life and the consequent reduction of physical and social activity contribute to the increased incidence of falls in older adults. Moreover, older adults suffer different kinds of cognitive decline, such as dementia or attention problems, which also accentuate gait disorders and its consequences. In this paper we present a methodology for gait identification using the on-board sensors of a smart rollator: the i-Walker. This technique provides the number of steps performed in walking exercises, as well as the time and distance travelled for each stride. It also allows to extract spatio-temporal metrics used in medical gait analysis from the interpretation of the interaction between the individual and the i-Walker. In addition, two metrics to assess users’ driving skills, laterality and directivity, are proposed.Peer ReviewedPostprint (author's final draft

Vitamin D and Brain Imaging in the Elderly: Should we Expect Some Lesions Specifically Related to Hypovitaminosis D?

Hypovitaminosis D is associated with cognitive decline in the elderly, but the issue of causality remains unresolved. Definitive evidence would include the visualization of brain lesions resulting from hypovitaminosis D. The aim of the present article is to determine, through a literature review, the location and nature of possible brain disorders in hypovitaminosis D. We found limited brain-imaging data, which reported ischemic infarcts and white matter hyperintensities in hypovitaminosis D, though did not provide their specific location or report any focal atrophy. Based on the finding of executive dysfunctions (i.e., mental shifting and information updating impairments) in the presence of hypovitaminosis D, we suggest that hypovitaminosis D is associated with a dysfunction of the frontal-subcortical neuronal circuits, particularly the dorsolateral circuit. Further imaging studies are required to corroborate this assumption and to determine whether hypovitaminosis D results in degenerative and / or vascular lesions

The apathy, gait impairment, and executive dysfunction (AGED) triad vascular variant

Apathy, gait disturbances, and executive dysfunction (AGED) often occur together. Although they can arise independently, the presence of one might portend another. This recognition suggests the possible etiology. We focus on the most common, the vascular. We explain the AGED vascular mechanism through the ambibaric brain concept. The brain contains two complementary blood pressure systems: One high in the primitive brain (brainstem, basal ganglia, and thalamus) and a low-pressure system in the Homo sapiens brain (cerebral hemispheres). Hypertension inflicts the most damage on the primitive brain. The frontal systems connect to the basal ganglia, then the thalamus and back to the cortex. Many connections converge on the primitive brain where they are damaged by vascular disease. We need methods of determining optimal, individual blood pressures. Although the AGED triad can result from other causes, it should first signal a vascular etiology, the most prevalent, treatable, and preventable one

Association of executive function impairment, history of falls and physical performance in older adults: A cross-sectional population-based study in Eastern France

To estimate: 1) the association between executive function (EF) impairment and falls; and 2) the association of EF impairment on tests of physical function used in the evaluation of fall risk.Cross-sectional study. Thirteen health examination centres in Eastern France. Four thousand four hundred and eighty one community-dwelling older adults without dementia aged 65 to 97 years (mean age 71.8 +/- 5.4, women 47.6%). Participants underwent a comprehensive medical assessment that included evaluations of EF using the Clock Drawing Test and of physical performance using the Timed Up & Go Test (TUG). Analysis used multivariable modified Poisson regression to evaluate the association between impaired EF and each of the fall outcomes (any fall, recurrent falls, fall-related injuries). Multivariable linear regression was used to evaluate the association between EF impairment and performance on the TUG and grip strength. EF impairment, assessed using the clock drawing test, was present in 24.9% of participants. EF impairment was independently associated with an increased risk of any fall (RR=1.13, 95% CI (1.03, 1.25)) and major soft tissue fall-related injury (RR= 2.42, 95% CI (1.47, 4.00)). Additionally, EF impairment was associated with worse performance on the TUG (p < 0.0001). EF impairment among older adults without dementia was highly prevalent and was independently associated with an increased risk for falls, fall-related injuries and with decreased physical function. The use of the Clock Drawing Test is an easy to administer measure of EF that can be used routinely in comprehensive fall risk evaluations