Exoskeleton Variability Optimization for Reducing Gait Variability for Patients With Peripheral Artery Disease
Exoskeleton Variability Optimization for Reducing Gait Variability for Patients With Peripheral Artery Disease
Exoskeletons, wearable devices that assist with walking, can improve mobility in clinical populations. With exoskeletons, it is crucial to optimize the assistance profile. Recent studies describe algorithms (i.e., human-in-the-loop) to optimize the assistance profile with real-time metabolic measurements. The needed duration of current human-in-the-loop (HITL) algorithms range from 20 minutes to 1 hour which is longer than the average duration that most patients with peripheral artery disease (PAD) can walk. Because of this limited walking duration, it is often not possible for patients with PAD to reach steady-state metabolic cost, which makes these measurements are not useful for optimizing exoskeletons. In this study, investigators intend to develop and evaluate HITL optimization methods for exoskeletons and use the information to design and evaluate a portable hip exoskeleton. Shorter and more clinically feasible HITL optimization strategies based on experiments in healthy adults might allow utilizing these optimization strategies to become available for patient populations such as patients with PAD.
Exoskeletons, wearable devices that assist with walking, can improve mobility in clinical populations. With exoskeletons, it is crucial to optimize the assistance profile. Recent studies describe algorithms (i.e., human-in-the-loop) to optimize the assistance profile with real-time metabolic measurements. The needed duration of current human-in-the-loop (HITL) algorithms range from 20 minutes to 1 hour which is longer than the average duration that most patients with peripheral artery disease (PAD) can walk. Because of this limited walking duration, it is often not possible for patients with PAD to reach steady-state metabolic cost, which makes these measurements are not useful for optimizing exoskeletons. Shorter and more clinically feasible HITL optimization strategies based on experiments in healthy adults might allow utilizing these optimization strategies to become available for patient populations such as patients with PAD.
This study will test different methods for optimizing exoskeletons. It will consist of an habituation session to the hip exoskeleton, an optimization session to find the optimal actuation settings using an algorithm that converges toward the optimum based on real-time measurements (human-in-the-loop algorithm) and a post-test at the end of optimization session to compare different conditions. The outcomes will be evaluated by surface electromyography, exoskeleton sensors, ground reaction force, walking speed, indirect calorimetry, and motion capture (Vicon).
Inclusion Criteria:
Ability to provide written consent
Chronic claudication history
Ankle-brachial index < 0.90 at rest
Stable blood pressure, lipids, and diabetes for > 6 weeks
Ability to walk on a treadmill for multiple five-minute spans
Ability to fit in exoskeleton
Exclusion Criteria:
Resting pain or tissue loss due to peripheral artery disease (PAD, Fontaine stage III and IV)
Foot ulceration
Acute lower extremity event secondary to thromboembolic disease or acute trauma
Walking capacity limited by diseases unrelated to PAD, such as:
Acute injury or pain in lower extremity
Current illness
Inability to follow visual cues due to blindness
Inability to follow auditory cues due to deafness
Pregnant