Evaluation of a finite state machine algorithm to measure stepping with ankle accelerometry: Performance across a range of gait speeds, tasks, and individual walking ability.

Wearable sensors, including accelerometers, are a widely accepted tool to assess gait in clinical and free-living environments. Methods to identify phases and subphases of the gait cycle are necessary for comprehensive assessment of pathological gait. The current study evaluated the accuracy of a finite state machine (FSM) algorithm to detect strides by identifying gait cycle subphases from ankle-worn accelerometry.

Link among apolipoprotein E E4, gait, and cognition in neurodegenerative diseases: ONDRI study.

Introduction: Apolipoprotein E E4 allele (APOE E4) and slow gait are independently associated with cognitive impairment and dementia. However, it is unknown whether their coexistence is associated with poorer cognitive performance and its underlying mechanism in neurodegenerative diseases.

Methods: Gait speed, APOE E4, cognition, and neuroimaging were assessed in 480 older adults with neurodegeneration.

Advances in mobility aid use reporting: situational context and objective measurement improve understanding of daily aid use in older adults.

Background: Understanding mobility aid use has implications for falls risk reduction and aid prescription. However, aid use in daily life is understudied and more complex than revealed by commonly used yes/no self-reporting.

Aims: To advance approaches for evaluating mobility aid use among older adults using a situational (context-driven) questionnaire and wearable sensors.

Emotional state as a modulator of autonomic and somatic nervous system activity in postural control: a review.

Advances in our understanding of postural control have highlighted the need to examine the influence of higher brain centers in the modulation of this complex function. There is strong evidence of a link between emotional state, autonomic nervous system (ANS) activity and somatic nervous system (somatic NS) activity in postural control. For example, relationships have been demonstrated between postural threat, anxiety, fear of falling, balance confidence, and physiological arousal.

User-centered design of feedback regarding health-related behaviors derived from wearables: An approach targeting older adults and persons living with neurodegenerative disease.

Objective: There has been tremendous growth in wearable technologies for health monitoring but limited efforts to optimize methods for sharing wearables-derived information with older adults and clinical cohorts. This study aimed to co-develop, design and evaluate a personalized approach for information-sharing regarding daily health-related behaviors captured with wearables.

Methods: A participatory research approach was adopted with: (a) iterative stakeholder, and evidence-led development of feedback reporting; and (b) evaluation in a sample of older adults (n  =  15) and persons living with neurodegenerative disease (NDD) (n  =  25).

Association of Dual-Task Gait Cost and White Matter Hyperintensity Burden Poststroke: Results From the ONDRI.

Background: Acute change in gait speed while performing a mental task [dual-task gait cost (DTC)], and hyperintensity magnetic resonance imaging signals in white matter are both important disability predictors in older individuals with history of stroke (poststroke). It is still unclear, however, whether DTC is associated with overall hyperintensity volume from specific major brain regions in poststroke.

Methods: This is a cohort study with a total of 123 older (69 ± 7 years of age) participants with history of stroke were included from the Ontario Neurodegenerative Disease Research Initiative.

Wrist Accelerometer Estimates of Physical Activity Intensity During Walking in Older Adults and People Living With Complex Health Conditions: Retrospective Observational Data Analysis Study.

Background: Accurate measurement of daily physical activity (PA) is important as PA is linked to health outcomes in older adults and people living with complex health conditions. Wrist-worn accelerometers are widely used to estimate PA intensity, including walking, which composes much of daily PA. However, there is concern that wrist-derived PA data in these cohorts is unreliable due to slow gait speed, mobility aid use, disease-related symptoms that impact arm movement, and transient activities of daily living.

White matter hyperintensity burden predicts cognitive but not motor decline in Parkinson's disease: results from the Ontario Neurodegenerative Diseases Research Initiative.

Background And Purpose: The pathophysiology of Parkinson's disease (PD) negatively affects brain network connectivity, and in the presence of brain white matter hyperintensities (WMHs) cognitive and motor impairments seem to be aggravated. However, the role of WMHs in predicting accelerating symptom worsening remains controversial. The objective was to investigate whether location and segmental brain WMH burden at baseline predict cognitive and motor declines in PD after 2 years.

Characteristics of the Ontario Neurodegenerative Disease Research Initiative cohort.

Introduction: Understanding synergies between neurodegenerative and cerebrovascular pathologies that modify dementia presentation represents an important knowledge gap.

Methods: This multi-site, longitudinal, observational cohort study recruited participants across prevalent neurodegenerative diseases and cerebrovascular disease and assessed participants comprehensively across modalities. We describe univariate and multivariate baseline features of the cohort and summarize recruitment, data collection, and curation processes.

Can we use peripheral vision to create a visuospatial map for compensatory reach-to-grasp reactions?

Perturbation-induced reach-to-grasp reactions are dependent on vision to capture environmental features of potential support surfaces. Previous research proposed the use of an intrinsic visuospatial map of the environment to reduce delays in motor responses (e.g.

Detecting accelerometer non-wear periods using change in acceleration combined with rate-of-change in temperature.

Background: Accelerometery is commonly used to estimate physical activity, sleep, and sedentary behavior. In free-living conditions, periods of device removal (non-wear) can lead to misclassification of behavior with consequences for research outcomes and clinical decision making. Common methods for non-wear detection are limited by data transformations (e.

Standing, Transition, and Walking Ability in Older Adults: The Case for Independently Evaluating Different Domains of Mobility Function.

Background: Independent mobility is a complex behavior that relies on the ability to walk, maintain stability, and transition between postures. However, guidelines for assessment that details what elements of mobility to evaluate and how they should be measured remain unclear.

Methods: Performance on tests of standing, sit-to-stand, and walking were evaluated in a cohort of 135 complex, comorbid, and older adults (mean age 87 ± 5.

Feasibility of a continuous, multi-sensor remote health monitoring approach in persons living with neurodegenerative disease.

Background: Remote health monitoring with wearable sensor technology may positively impact patient self-management and clinical care. In individuals with complex health conditions, multi-sensor wear may yield meaningful information about health-related behaviors. Despite available technology, feasibility of device-wearing in daily life has received little attention in persons with physical or cognitive limitations.

Older Adults' Drop in Cerebral Oxygenation on Standing Correlates With Postural Instability and May Improve With Sitting Prior to Standing.

Background: Impaired blood pressure (BP) recovery with orthostatic hypotension on standing occurs in 20% of older adults. Low BP is associated with low cerebral blood flow but mechanistic links to postural instability and falls are not established. We investigated whether posture-related reductions in cerebral tissue oxygenation (tSO2) in older adults impaired stability upon standing, if a brief sit before standing improved tSO2 and stability, and if Low-tSO2 predicted future falls.

A History of Concussion Affects Relevancy-Based Modulation of Cortical Responses to Tactile Stimuli.

Modulating cortical excitability based on a stimulus' relevance to the task at hand is a component of sensory gating, and serves to protect higher cortical centers from being overwhelmed with irrelevant information (McIlroy et al., 2003; Kumar et al., 2005; Wasaka et al.

Exploring the role of applied force eccentricity after foot-contact in managing anterior instability among older adults during compensatory stepping responses.

Background: The specific mechanisms responsible for age-related decline in forward stability control remain unclear. Previous work has suggested reactive control of net ground reaction force (GRF) eccentricity may be responsible for age-related challenges in mediolateral stability control during the restabilisation phase of forward compensatory stepping responses.

Research Questions: Does reactive control of GRF eccentricity play a role in managing forward stability control during the restabilisation phase of a forward stepping response to external balance perturbation?

Methods: Healthy younger (YA) (n = 20) and older adults (OA) (n = 20) were tethered to a rigid frame, via adjustable cable.

A role for the lower visual field information in stair climbing.

Background: Locomotion on stairs is challenging for balance control and relates to a significant number of injurious falls. The visual system provides relevant information to guide stair locomotion and there is evidence that peripheral vision is potentially important.

Research Question: This study investigated the role of the lower visual field information for the control of stair walking.

Online Learning of Gait Models From Older Adult Data.

This paper proposes a novel approach for online, individualized gait analysis, based on an adaptive periodic model of any gait signal. The proposed method learns a model of the gait cycle during online measurement, using a continuous representation that can adapt to inter- and intra-personal variability by creating an individualized model. Once the algorithm has converged to the input signal, key gait events can be identified based on the estimated gait phase and amplitude.

Activity in Functional Cortical Networks Temporally Associated with Postural Instability.

Human bipedal balance control is proposed to be the integrated activity of distributed neural areas. There is growing understanding about the cortical involvement in this highly automated behavior. While evidence exists for cortical activity temporally linked to reactive balance control, little is known about the functional interaction of potential cortical regions.

Stroke.

Stroke, or cerebrovascular accident, involves injury to the central nervous system as a result of a vascular cause, and is a leading cause of disability worldwide. People with stroke often experience sensory, cognitive, and motor sequelae that can lead to difficulty walking, controlling balance in standing and voluntary tasks, and reacting to prevent a fall following an unexpected postural perturbation. This chapter discusses the interrelationships between stroke-related impairments, problems with control of balance and gait, fall risk, fear of falling, and participation in daily physical activity.

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

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.

Dual-Task Elderly Gait of Prospective Fallers and Non-Fallers: A Wearable-Sensor Based Analysis.

Wearable sensors could facilitate point of care, clinically feasible assessments of dynamic stability and associated fall risk through an assessment of single-task (ST) and dual-task (DT) walking. This study investigated gait changes between ST and DT walking and between older adult prospective fallers and non-fallers. The results were compared to a study based on retrospective fall occurrence.

SYNERGIC TRIAL (SYNchronizing Exercises, Remedies in Gait and Cognition) a multi-Centre randomized controlled double blind trial to improve gait and cognition in mild cognitive impairment.

Background: Physical exercise, cognitive training, and vitamin D are low cost interventions that have the potential to enhance cognitive function and mobility in older adults, especially in pre-dementia states such as Mild Cognitive Impairment (MCI). Aerobic and progressive resistance exercises have benefits to cognitive performance, though evidence is somewhat inconsistent. We postulate that combined aerobic exercise (AE) and progressive resistance training (RT) (combined exercise) will have a better effect on cognition than a balance and toning control (BAT) intervention in older adults with MCI.

Frontal alpha asymmetry and aerobic exercise: are changes due to cardiovascular demand or bilateral rhythmic movement?

The left and right prefrontal cortices are linked to networks that control approach and withdrawal motivation, respectively. The relationship between activity in the left and right prefrontal activity is used to assess brain states and specifically their link to motivational behaviours and tendencies. The most common measure used in this context is called the frontal alpha asymmetry (FAA), which compares alpha (8-13Hz) power at each region.