Technological advancements have led to the development of numerous wearable robotic devices for the physical assistance and restoration of human locomotion. While many challenges remain with respect to the mechanical design of such devices, it is at least equally challenging and important to develop strategies to control them in concert with the intentions of the user. This work reviews the state-of-the-art techniques for controlling portable active lower limb prosthetic and orthotic (P/O) devices in the context of locomotive activities of daily living (ADL), and considers how these can be interfaced with the user’s sensory-motor control system. This review underscores the practical challenges and opportunities associated with P/O control, which can be used to accelerate future developments in this field. Furthermore, this work provides a classification scheme for the comparison of the various control strategies. As a novel contribution, a general framework for the control of portable gait-assistance devices is proposed. This framework accounts for the physical and informatic interactions between the controller, the user, the environment, and the mechanical device itself. Such a treatment of P/Os – not as independent devices, but as actors within an ecosystem – is suggested to be necessary to structure the next generation of intelligent and multifunctional controllers. Each element of the proposed framework is discussed with respect to the role that it plays in the assistance of locomotion, along with how its states can be sensed as inputs to the controller. The reviewed controllers are shown to fit within different levels of a hierarchical scheme, which loosely resembles the structure and functionality of the nominal human central nervous system (CNS). Active and passive safety mechanisms are considered to be central aspects underlying all of P/O design and control, and are shown to be critical for regulatory approval of such devices for real-world use. The works discussed herein provide evidence that, while we are getting ever closer, significant challenges still exist for the development of controllers for portable powered P/O devices that can seamlessly integrate with the user’s neuromusculoskeletal system and are practical for use in locomotive ADL.

/pdf/control-strategies-for-active-lower-extremity-prosthetics-5ojhkwsifh.pdf

Control strategies for active lower extremity prosthetics and orthotics: a review

Stroke patients have impaired physical fitness and this may exacerbate their disability. It is not known whether improving physical fitness after stroke reduces disability. Objectives The primary aims were to establish whether physical fitness training reduces death, dependence and disability after stroke. The secondary aims included an investigation of the effects of fitness training on secondary outcome measures (including, physical fitness, mobility, physical function, health and quality of life, mood and the incidence of adverse events). Randomised controlled trials were included when an intervention represented a clear attempt to improve either muscle strength and/or cardiorespiratory fitness, and whose control groups comprised either usual care or a non-exercise intervention. A total of 12 trials were included in the review. No trials reported death and dependence data. Two small trials reporting disability showed no evidence of benefit. The remaining available secondary outcome data suggest that cardiorespiratory training improves walking ability (mobility). Observed benefits appear to be associated with specific or 'task-related' training.

/pdf/physical-fitness-training-for-stroke-patients-29s61ki4l4.pdf

Physical fitness training for stroke patients

Annually, 700 000 people in the United States suffer a stroke, or ≈1 person every 45 seconds, and nearly one third of these strokes are recurrent.1 More than half of men and women under the age of 65 years who have a stroke die within 8 years.1 Although the stroke death rate fell 12% from 1990 to 2000, the actual number of stroke deaths increased by 9.9%. This represents a leveling off of prior declines.2 Moreover, the incidence of stroke is likely to continue to escalate because of an expanding population of elderly Americans; a growing epidemic of diabetes, obesity, and physical inactivity among the general population; and a greater prevalence of heart failure patients.3 When considered independently from other cardiovascular diseases, stroke continues to be the third leading cause of death in the United States.

Improved short-term survival after a stroke has resulted in a population of an estimated 4 700 000 stroke survivors in the United States.1 The majority of recurrent events in stroke survivors are recurrent strokes, at least for the first several years.4 Moreover, individuals presenting with stroke frequently have significant atherosclerotic lesions throughout their vascular system and are at heightened risk for, or have, associated comorbid cardiovascular disease.5,6 Accordingly, recurrent stroke and cardiac disease are the leading causes of mortality in stroke survivors.

Both coronary artery disease (CAD) and ischemic stroke share links to many of the same predisposing, potentially modifiable risk factors (hypertension, abnormal blood lipids and lipoproteins, cigarette smoking, physical inactivity, obesity, and diabetes mellitus), which highlights the prominent role lifestyle plays in the origin of stroke and cardiovascular disease.5,7,8 Modification of multiple risk factors through a combination of comprehensive lifestyle interventions and appropriate pharmacological therapy is now recognized as the cornerstone of initiatives aimed …

Physical Activity and Exercise Recommendations for Stroke Survivors An American Heart Association Scientific Statement From the Council on Clinical Cardiology, Subcommittee on Exercise, Cardiac Rehabilitation, and Prevention; the Council on Cardiovascular Nursing; the Council on Nutrition, Physical Activity, and Metabolism; and the Stroke Council

The metabolic energy cost of walking is determined, to a large degree, by body mass, but it is not clear how body composition and mass distribution influence this cost. We tested the hypothesis tha...

https://www.physiology.org/doi/pdf/10.1152/japplphysiol.00767.2005

Effects of obesity and sex on the energetic cost and preferred speed of walking.

Energy expenditure and biomechanical characteristics of lower limb amputee gait:: The influence of prosthetic alignment and different prosthetic components

Robert L. Waters

Papers

The energy expenditure of normal and pathologic gait.

Energy expenditure in elderly patients using assistive devices