Valerie Power

Predicting falls in community-dwelling older adults: A systematic review of task performance-based assessment tools

INTRODUCTION: Falls among community-dwelling older adults are a common yet often preventable occurrence. Clinicians frequently use task-based assessment tools to evaluate clients’ balance and mobility with the aim of predicting falls and providing targeted fall prevention interventions, but no consensus exists on the optimum tool(s) to use for this purpose. This review aims to identify the task-based assessment tools that can best predict falls among community-dwelling older adults. METHODS: Online databases Academic Search Complete, AMED, Biomedical Reference Collection: Expanded, CINAHL Plus, MEDLINE, General Science, and SPORTDiscus were searched from 1983 to 2013 to identify prospective studies assessing the performance of specific tasks in order to predict falls. Following screening, the methodological quality of studies included for review was appraised using a checklist based on the Critical Appraisal Skills Programme tool for cohort studies [1]. RESULTS: Thirty-seven studies, dating from 1996 to 2013 and largely of high methodological quality, were included in this review. A range of task performance-based assessment tools suitable for use in both clinical and laboratory settings were identified. CONCLUSIONS: Strong evidence in favour of using the Timed Up-and-Go test, Five Times Sit-to-Stand test and assessments of gait speed to predict falls among this population in clinical settings was found, along with weaker evidence for tests of standing balance and reaching task performance. Laboratory-based assessments of postural sway and gait variability were also found to predict falls. Incorporating the recommended assessment tools into comprehensive assessments of community-dwelling older clients can lead to improved falls prediction by clinicians.

Rationale, implementation and evaluation of assistive strategies for an active back-support exoskeleton

Active exoskeletons are potentially more effective and versatile than passive ones, but designing them poses a number of additional challenges. An important open challenge in the field is associated to the assistive strategy, by which the actuation forces are modulated to the user’s needs during the physical activity. This paper addresses this challenge on an active exoskeleton prototype aimed at reducing compressive low-back loads, associated to risk of musculoskeletal injury during manual material handling (i.e., repeatedly lifting objects). An analysis of the biomechanics of the physical task reveals two key factors that determine low-back loads. For each factor, a suitable control strategy for the exoskeleton is implemented. The first strategy is based on user posture and modulates the assistance to support the wearer’s own upper body. The second one adapts to the mass of the lifted object and is a practical implementation of electromyographic control. A third strategy is devised as a generalized combination of the first two. With these strategies, the proposed exoskeleton can quickly adjust to different task conditions (which makes it versatile compared to using multiple, task-specific, devices) as well as to individual preference (which promotes user acceptance). Additionally, the presented implementation is potentially applicable to more powerful exoskeletons, capable of generating larger forces. The different strategies are implemented on the exoskeleton and tested on 11 participants in an experiment reproducing the lifting task. The resulting data highlights that the strategies modulate the assistance as intended by design, i.e., they effectively adjust the commanded assistive torque during operation based on user posture and external mass. The experiment also provides evidence of significant reduction in muscular activity at the lumbar spine (around 30%) associated to using the exoskeleton. The reduction is well in line with previous literature and may be associated to lower risk of injury.

Exploring User Requirements for a Lower Body Soft Exoskeleton to Assist Mobility

The XoSoft (www.xosoft.eu) project -- funded under the European Unions Horizon 2020 framework programme -- aims to develop a lower body soft exoskeleton to assist adults with mobility impairments. The XoSoft concept is being developed via an iterative user centered design process, with user requirements driving technical innovations. This paper describes a semi-structured interview study undertaken in the initial stages of the project to determine Primary User (PU) and Secondary User (SU) requirements in relation to the function and design of the XoSoft concept. Fifteen PUs and 26 SUs were interviewed to explore their needs for mobility assistance, their experiences and requirements of mobility-related assistive devices, and their opinions on an initial portrayal of the XoSoft concept. Users provided valuable insights into their requirements in the following domains: desired functions and benefits of a device, practicability, training and support, design and aesthetics, and costs. Opinions of PUs and SUs of the XoSoft concept were largely positive, and a number of valuable design considerations were highlighted. The findings of this study will inform the design brief and technical specifications for XoSoft, and will assist the development of an alpha-prototype of the concept. Our results will also contribute to the evidence base available to all involved in the research and development of assistive devices for mobility, by giving voice to users and describing their needs/ wants in relation to such devices.

User Centered Design and Usability of Bionic Devices

User Centered Design of bionic and assistive devices is growing in importance as many technologies are now moving from lab concepts to certified medical products for use in daily life. The enthusiasm to develop new technologies often focuses on the scientific requirements but often very practical user requirements are over looked. This presentation discusses the role of user centered design in bionics development and how this relates to usability in use. The presentation frames the importance of usability and user centered design on technology acceptance, generally by users, but also with focus on technology acceptance and adoption by older age adults.

XoSoft : a vision for a soft modular lower limb exoskeleton

XoSoft is an EU project that proposes the development of a modular soft lower-limb exoskeleton to assist people with mobility impairments. It aims to be user friendly and comfortable to wear, with a significant impact on the person’s mobility and health, on their independence and quality of life. Being a modular system, it comprises of ankle, knee and hip elements, which can be used individually or combined and used unilaterally or bilaterally.

The Effects of Rearfoot Position on Lower Limb Kinematics during Bilateral Squatting in Asymptomatic Individuals with a Pronated Foot Type.

The Effects of Rearfoot Position on Lower Limb Kinematics during Bilateral Squatting in Asymptomatic Individuals with a Pronated Foot Type Clinicians frequently assess movement performance during a bilateral squat to observe the biomechanical effects of foot orthotic prescription. However, the effects of rearfoot position on bilateral squat kinematics have not been established objectively to date. This study aims to investigate these effects in a population of healthy adults with a pronated foot type. Ten healthy participants with a pronated foot type bilaterally (defined as a navicular drop >9mm) performed three squats in each of three conditions: barefoot, standing on 10mm shoe pitch platforms and standing on the platforms with foam wedges supporting the rearfoot in subtalar neutral. Kinematic data was recorded using a 3D motion analysis system. Between-conditions changes in peak joint angles attained were analysed. Peak ankle dorsiflexion (p=0.0005) and hip abduction (p=0.024) were significantly reduced, while peak knee varus (p=0.028) and flexion (p=0.0005) were significantly increased during squatting in the subtalar neutral position compared to barefoot. Peak subtalar pronation decreased by 5.33° (SD 4.52°) when squatting on the platforms compared to barefoot (p=0.006), but no additional significant effects were noted in subtalar neutral. Significant changes in lower limb kinematics may be observed during bilateral squatting when rearfoot alignment is altered. Shoe pitch alone may significantly reduce peak pronation during squatting in this population, but additional reductions were not observed in the subtalar neutral position. Further research investigating the effects of footwear and the subtalar neutral position in populations with lower limb pathology is required.

Technology Acceptance and User-Centred Design of Assistive Exoskeletons for Older Adults: A Commentary

Assistive robots are emerging as technologies that enable older adults to perform activities of daily living with autonomy. Exoskeletons are a subset of assistive robots that can support mobility. Perceptions and acceptance of these technologies require understanding in a user-centred design context to ensure optimum experience and adoption by as broad a spectrum of older adults as possible. The adoption and use of assistive robots for activities of daily living (ADL) by older adults is poorly understood. Older adult acceptance of technology is affected by numerous factors, such as perceptions and stigma associated with dependency and ageing. Assistive technology (AT) models provide theoretical frameworks that inform decision-making in relation to assistive devices for people with disabilities. However, technology acceptance models (TAMs) are theoretical explanations of factors that influence why users adopt some technologies and not others. Recent models have emerged specifically describing technology acceptance by older adults. In the context of exoskeleton design, these models could influence design approaches. This article will discuss a selection of TAMs, displaying a chronology that highlights their evolution, and two prioritised TAMs—Almere and the senior technology acceptance model (STAM)—that merit consideration when attempting to understand acceptance and use of assistive robots by older adults.

Basic functionality of a prototype wearable assistive soft exoskeleton for people with gait impairments: a case study

XoSoft is a soft modular wearable assistive exoskeleton for people with mild to moderate gait impairments. It is currently being developed by a European Consortium (www.xosoft.eu) and aims to provide tailored and active lower limb support during ambulation. During development, user-centered design principles were followed in parallel with the aim of providing functional support during gait. A prototype was developed and was tested for practicability, usability, comfort and assistive function (summarized as basic functionality) with a potential end user. The prototype consisted of a garment, electromagnetic clutch-controlled elastic bands supporting knee- and hip flexion and a backpack containing the sensor and actuator control of the system. The participant had experienced a stroke and presented with unilateral impairment of the lower and upper extremities. In testing, he donned and doffed the prototype independently as far as possible, and performed walking trials with the system in both active (powered on) and passive (powered off) modes. Afterwards, the participant rated the perceived pressure and various elements of usability. Results highlighted aspects of the system for improvement during future phases of XoSoft development, and also identified useful aspects of prototype design to be maintained. The basic functionality of XoSoft could be assumed as satisfactory given that it was the first version of a working prototype. The study highlights the benefits of this participatory evaluation design approach in assistive soft robotics development.

AXO-SUIT - A Modular Full-Body Exoskeleton for Physical Assistance

This paper presents the design of a modular full-body assistive exoskeleton (FB-AXO) for older adults which was developed with funding under the AAL funded AXO-SUIT project. Processes used to formulate a prioritized set of functional and design requirements via close end-user involvement are outlined and used in realising the exoskeleton. Design of the resulting mechanics and electronics details for the lower- and upper-body subsystems (LB-AXO and (UB-AXO)) are described. Innovative designs of shoulder and spine mechanisms are presented. The FB-AXO system comprises 27 degrees of freedom, of which 17 are passive and 10 active. The exoskeleton assists full-body motions such as walking, standing, bending, as well as performing lifting and carrying tasks to assist older users performing tasks of daily living.

Development and Testing of Full-Body Exoskeleton AXO-SUIT for Physical Assistance of the Elderly

This paper presents the design and preliminary testing of a full-body assistive exoskeleton AXO-SUIT for older adults. AXO-SUIT is a system of modular exoskeletons consisting of lower-body and upper-body modules, and their combination as full body as well to provide flexible physical assistance as needed. The full-body exoskeleton comprises 27 degrees of freedom, of which 17 are passive and 10 active, which is able to assist people in walking, standing, carrying and handling tasks. In the paper, design of the AXO-SUIT is described. End-user testing results are presented to show the effectiveness of the exoskeleton in providing flexible physical assistance.