Daniel P. Ferris, Ph.D. - US grants

[unreadable] DESCRIPTION (provided by applicant): Recent research suggests that locomotor training can improve human walking ability after neurological injury. When stroke and spinal cord injury patients practice stepping with manual assistance, they recover mobility more quickly due to task-specific motor learning. Although multiple studies support the efficacy of this rehabilitation method, there is considerable debate about the extent of motor adaptation possible in the human locomotor pattern. Some animal and clinical studies indicate that muscle activation patterns during locomotion are hardwired into the nervous system and incapable of substantial modification. This would suggest that there are limits to locomotor training as a therapeutic tool. The proposed research project will use powered ankle-foot orthoses to study human locomotor adaptation. The powered orthoses will exert a torque about the ankle joint, altering normal lower limb kinematics if muscle activity patterns are not modified. As a result, these studies will test the relative invariance of muscle activity patterns and lower limb kinematics during human locomotion. This will not only provide the opportunity to study human locomotor adaptation under controlled experimental conditions, it will also provide a means to test the hypothesis that the nervous system controls lower limb movements during locomotion based on kinematics. The overall objectives of the proposed research are 1) to determine the extent of motor adaptation possible in the human locomotor pattern and 2) to test and hypothesized neural control strategy for human walking. Healthy human subjects will walk while wearing carbon fiber ankle-foot orthoses that are powered by artificial pneumatic muscles and controlled via proportional myoelectrical control. The studies will test the hypothesis that subjects will modify their muscle activity patterns when walking with powered orthoses to maintain joint kinematics similar to normal walking. In addition to providing important insight into the neural control of human locomotion, the project will advance robotic technologies for assisting gait rehabilitation and controlling powered lower limb prostheses.

0347479
Ferris
This five-year CAREER Development project will examine the biomechanics and energetics of human locomotion with powered lower limb exoskeletons. The Human Neuromechanics Laboratory at The University of Michigan has developed carbon fiber lower limb exoskeletons that can comfortably supply active torque assistance at the ankle, knee, and hip during walking and running. Artificial pneumatic muscles attached to a carbon fiber shell provide high power outputs while minimizing exoskeleton weight. Myoelectrical signals from biological muscles control force in the artificial muscles in a physiologically appropriate manner. Although the exoskeletons are limited to laboratory use because they require a large source of compressed air, they are ideal for studying human responses to powered locomotor assistance.

The objective of the research plan is to quantify the effects of powered assistance on the energetics of walking and running. The investigators will measure the metabolic efficiency of external power assistance at the ankle, knee, and hip during walking and running over a range of speeds and added loads. The results will provide important insight into the mechanical factors that determine the metabolic cost of locomotion and much needed guidance for creation of future lower limb exoskeletons. The biomechanical and metabolic benefit of adding external power to the ankle vs. knee vs. hip will be quantified. These data will be instrumental in performing cost-benefit analyses of actuator and exoskeleton design for gait rehabilitation and human performance augmentation.

The objective of the educational plan is to use exoskeleton research to introduce problem-based discovery learning into the curriculum of students preparing for health science careers. The plan includes: a) creating an upper division course on gait biomechanics that incorporates hands-on experimentation and testing related to exoskeletons for human augmentation and rehabilitation, b) recruiting and training female and minority undergraduate students for exoskeleton research projects in the Human Neuromechanics Laboratory, and c) creating an interactive web page on robotic exoskeletons that can be used as an educational resource for secondary and undergraduate students.

DESCRIPTION (provided by applicant): We have developed a powered ankle-foot orthosis that can assist human walking. The ankle-foot orthosis has an artificial pneumatic muscle providing plantar flexor torque in response to soleus muscle activation (i.e. proportional myoelectric control). We focus on robotic assistance for the ankle because plantar flexion during stance is a major source of mechanical power during walking and is directly related to walking ability in individuals with neurological disability. Neurologically intact subjects wearing the orthoses rapidly adapt their muscle activation patterns to compensate for the added mechanical power provided by the orthoses. We propose to determine if subjects with incomplete spinal cord injury benefit from practice walking with the powered orthoses. Our preliminary data suggest that proportional myoelectric control provides a powerful stimulus for re-shaping muscle activation patterns in subjects with incomplete spinal cord injury. The orthosis effectively makes the muscle stronger. This provides the nervous system with enhanced proprioceptive feedback linking muscle recruitment to joint motion. This innovative approach is unique as other robotic rehabilitation devices rely on an external agent (i.e. a computer) to control the timing and magnitude of mechanical assistance rather than the patient's own nervous system as we propose. We will measure H-reflexes, electromyography, kinematics, kinetics, and metabolic cost in individuals with incomplete spinal cord injury before and after eight weeks of practice walking with the orthoses. The results will provide sufficient data to design an extended randomized clinical trial of the powered orthosis. PUBLIC HEALTH RELEVANCE: We will study people with incomplete spinal cord injury walking with robotic braces on their legs to determine if the braces can improve their walking ability. The results may lead to new robotic therapies for improving rehabilitation after spinal cord injury or stroke.

DESCRIPTION (provided by applicant): There is an important clinical need to develop functional imaging techniques that can quantify brain processes during human locomotion and relate them to body dynamics. Mobile brain imaging could assist with the diagnosis and treatment of patients with numerous movement disorders and neurological injuries. We propose that Independent Component Analysis of high-density electroencephalography (EEG) can quantify distinct brain processes involved in the control of human gait. Furthermore, we contend that electrocortical brain processes identified using Independent Component Analysis of EEG correlate with whole body dynamics. We will study healthy young subjects performing various locomotor tasks while we record movement kinematics and 256-channel EEG using active scalp electrodes. In Specific Aim 1, we will examine subjects walking at a range of speeds to determine if intra-stride patterns of activation and deactivation synchronized to the gait cycle are consistent across walking speeds. In Specific Aim 2, we will examine subjects performing passive recumbent stepping and active recumbent stepping to determine the relative effects of sensory feedback vs. motor feed forward commands with sensory feedback on electrocortical brain processes. We hypothesize that passive recumbent stepping will engage fewer electrocortical sources than active recumbent stepping. We will also compare active recumbent stepping with treadmill walking to determine the similarities between recumbent stepping and walking in activating cortical brain processes. In Specific Aim 3, we will examine subjects walking on a split-belt treadmill to quantify sensorimotor hemispheric independence using coherence. In Specific Aim 4, we will study subjects walking on a narrow treadmill-mounted balance beam to identify the electrocortical processes involved in maintaining and monitoring balance. The results from this study will advance our understanding of electrocortical dynamics related to the control of human walking, and will lead to new studies probing mechanisms of neurological gait impairments. The findings could also facilitate new brain- machine interface technologies for controlling robotic orthoses or prostheses. PUBLIC HEALTH RELEVANCE: We will use head mounted electrodes and signal processing techniques to identify brain activity related to the control of human walking. The results may lead to new imaging techniques for studying brain function during diagnosis and rehabilitation of movement disorders.

? DESCRIPTION (provided by applicant): The 2016 Biomechanics and Neural Control of Movement meeting will bring together experts in musculoskeletal biomechanics, neuroscience, muscle physiology, clinical medicine, and biomedical engineering on the 20th anniversary of a seminal meeting on the same topic. The 1996 meeting had a profound impact on human movement science. Many of the world's best scientists and engineers studying motor control and rehabilitation interacted directly with postdoctoral scholars and graduate students at a small, isolated conference center. A large percentage of the graduate students and postdoctoral scholars that attended the 1996 meeting went on to become leaders in their fields. We will hold the 2016 Biomechanics and Neural Control of Movement meeting at the same conference center in Mt. Sterling, OH, and use a similar meeting format to generate open discussion and debate about the current state of the science of human movement control and rehabilitation. The meeting will have a single presentation track to bring together all 120 attendees in one room and extensive time will be scheduled for discussions around the presentations. This proposal seeks to obtain funding for 20 graduate student/postdoctoral researcher travel awards in order to defray costs of attendance for the next generation of human movement science scholars. At least half of the travel awards will go to individuals from underrepresented backgrounds based on race, ethnicity, disability status, or sex. The meeting will also include a one-to-one mentoring program for graduate students and postdoctoral scholars to foster networking and interaction between attendees from different institutions. The requested funds will help make the meeting available to a wider possible audience and encourage the success of future biomedical research leaders.

On June 12-17, 2016, experts on the biology and engineering of human and animal movement will assemble at the Deer Creek Conference Center and Lodge in Mt. Sterling, OH, for a conference entitled, "Biomechanics and Neural Control of Movement". The goal of the meeting is to promote intensive open-ended debate about the current state of knowledge and areas of future research on human and animal movement. Specific sessions will cover muscle, bone, locomotion, reaching and grasping, modeling, and rehabilitation. The unique venue, isolated from distractions, and the inclusion of experts from many different scientific fields should make this conference different from many annually occurring conferences that are focused on narrower aspects of human and/or animal movement. The proposal seeks funding to publish the consensus findings of the expert panels of the meeting to serve as a roadmap for scientists, engineers, and program managers for federal funding agencies. The outcome should lead to greater scientific advances in the treatment of individuals with movement disabilities, creation of new technology for assisting human movement, and the design of robots emulating biological movement.

This conference proposal requests support for journal publication charges. 45 invited experts in muscle biology, movement energetics, skeletal biomechanics, neuromotor adaptation, locomotion, sensorimotor control, rehabilitation robotics, and neuromusculoskeletal modeling will come together in a conference center isolated from a major city. The remote location, relatively small size (140 attendees), and ample discussion time in the program should provide for considerable opportunity to have productive debate on current understanding of the physiology and engineering of movement. Roboticists, computer scientists, physiologists, kinesiologists, clinicians, and biomedical engineers will bring their disparate perspectives to the meeting. There are 9 invited panels with five speakers each. Each panel will prepare a summary review journal paper for publication in a special issue of an open access journal (e.g. Journal of Neural Engineering) to disseminate the discussion and findings of the panel. The funding from this award will go towards the page charges for the special issue.

Technology for mobile brain imaging with electroencephalography (EEG) has advanced in recent years, but it is still difficult to capture electrical brain dynamics while people move in the real world. The body movement of walking and running creates considerable motion and muscle artifacts, making it difficult to determine what is true brain activity. This project proposes to advance electrode technology and signal processing of EEG to enable measurement of brain electrical activity outside the laboratory in the real world, including playing tennis, a complex, active, goal-directed motor task. The project will use novel methods to measure brain electrical activity as people walk on a university campus. Some subjects will be physically intact; some will have lower limb amputations. The technological and scientific advancements from these studies will permit future use of mobile EEG for clinical diagnosis and rehabilitation, as well as development of new mobile brain computer interfaces.

To understand how the human brain works in the real world, it is necessary to study human brain dynamics in real-world environments and tasks. Stationary functional brain imaging techniques like magnetic resonance imaging and magnetoencephalography are inherently limited in studying brain function of people moving through the real world. Creating and validating new mobile brain imaging methods with both good temporal and spatial resolution are necessary to advance neuroscience and facilitate non-invasive brain computer interfaces for real-world use. This project will combine high-density EEG with independent component analysis and source localization to identify brain areas involved in the control and active perception of moving in real-world urban and natural environments and in playing tennis. Motion and muscle artifacts complicate interpretation of EEG data during active whole body movement. New hardware and software solutions are necessary to increase the quality of EEG as a mobile brain imaging tool during locomotion. This project will advance novel dual-layer EEG electrodes that can cancel motion artifacts and improve the fidelity of electrocortical measures. The project combines cognitive neuroscience, signal processing, sensor technology, biomechanics, and motor control to make recordings of human brain dynamics that have never been made before. The advances and validation of neurotechnology will provide neuroscientists with new capabilities to transform the study of human brain function in the real world. This research will advance technology for mobile brain imaging and provide new insight into the cortical control of human movement in health and disability.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

Title Supraspinal Control of Human Locomotor Adaptation Abstract Advances in electroencephalography (EEG) technology have made it feasible to study electrical brain dynamics during human gait. Active electrodes, novel signal processing approaches, and subject-specific inverse electrical head models allow for unprecedented insight into how the human brain controls locomotion. Further advances in EEG based mobile brain imaging will increase our fundamental understanding of how the human brain works in real world situations, improve diagnosis and treatment of movement disorders, and result in new brain- computer interfaces. We recently developed a novel noise-cancelling EEG system that can greatly improve the signal to noise ratio for EEG. We propose to use our novel EEG system to investigate human locomotor adaptation. Many studies have used blood-oxygen-level dependent imaging (e.g. fMRI or fNIRS) to study supraspinal control of upper limb motor adaptation or imagined human walking, but the timescale of those imaging modalities do not allow for identifying brain activity relative to the biomechanics of the gait cycle. We propose to use our novel EEG system to document the brain areas involved in locomotor adaptation. Specifically, we will quantify brain activity spectral fluctuations within the gait cycle that demonstrate correlations with locomotor adaptation. We expect that multiple brain areas, including the anterior cingulate, cerebellum, somatosensory cortex, and motor cortex are likely involved in the control and adaptation of walking. We also expect that areas involved in locomotor adaptation will decrease spectral power fluctuations with improvements in locomotor performance during challenging gait tasks. The specific tasks that we will investigate are walking at different speeds, walking on a split-belt treadmill, walking with a unilateral robotic ankle exoskeleton, and walking on a balance beam with visual perturbations. The high temporal resolution of EEG provides particularly valuable insight into both amplitude and timing of brain activity within the gait cycle. Our preliminary data suggest that there are more cortical areas involved in controlling human walking than are generally recognized in the literature. The results from these studies will increase our basic science understanding of the supraspinal control of human locomotor adaptation and should lead to further advances in EEG mobile brain imaging technology.