Award Partner: Praxis Spinal Cord Institute

An advanced wearable robotic exoskeleton for assisting people with lower limb disabilities

Human locomotion is influenced by many factors, including neuromuscular and joint disorders that affect the functionality of joints and can cause partial or complete paralysis. Reduced mobility is estimated to affect over 1.5 million people in the United States alone. Many individuals require mobility assistive technologies to keep up with their daily life, and the demand for these devices increases with age.

A wearable robotic exoskeleton is an external structural mechanism with joints and links corresponding to those of a human body. It is synchronized with the motion of a human body to enhance or support natural body movements. The exoskeleton transmits torques through links to the human joints and augments human strength.

Dr. Arzanpour has developed a novel wearable robotic exoskeleton for assisting people with lower limb disabilities, such as spinal cord injury patients. The robot is highly versatile and capable of guiding the lower limb joints to perform all normal and complex movements. The technology is light, modular, portable, programmable and relatively inexpensive, and is particularly innovative in its versatile hip, knee and ankle joint mechanism, such that the normal range of motion of the natural joints is preserved.

So far, a proof-of-concept prototype of the proposed lower limb exoskeleton has been fabricated and successfully tested on an anthropomorphic test dummy. With further progress this technology could help people with lower limb disabilities to walk again and greatly improve their quality of life.

Near infrared spectroscopy for the hemodynamic monitoring of acute spinal cord injury

One of the only treatments that could potentially improve paralysis in patients who have suffered an acute traumatic spinal cord injury (SCI) is the elevation of the mean arterial blood pressure (MAP) to provide enough blood supply to the injured spinal cord. It is, however, difficult to know what the MAP target should be for a given patient to optimize their neurologic recovery.

Currently there is no measurement tool that provides real-time information about the spinal cord blood supply and oxygenation, and allows them to know if their efforts to elevate blood pressure are actually improving (or worsening) the injured spinal cord. Such a tool would provide information to guide clinicians in their treatment decisions and allow them to personalize their care and optimize neurologic outcomes.

Dr. Kwon will explore the potential of near-infrared spectroscopy (NIRS) as a monitoring tool to provide this information, with the explicit goal of developing this technology into a device that can be commercialized to be used in SCI patients. NIRS works by shining near-infrared (NIR) light through tissues and then recording how much light is transmitted versus how much is absorbed by molecules within the tissue. By measuring near infrared light absorption in tissue, NIRS can measure how much oxygen and blood is being delivered, potentially informing us of whether cells within the tissue are being irreversibly injured due to oxygen deprivation.

Dr. Kwon’s research will translate a promising technology (NIRS) into a clinical application for acute SCI patients. His initiative is focused on providing a tool that will assist clinicians in their hemodynamic management of acutely injured patients during a time when their efforts greatly impact patients’ neurologic outcomes.

End of Award Update: February 2023

 
Most exciting outputs

Product/technology – Near Infrared Spectroscopy (NIRS) Biosensor for the Spinal Cord. We managed to bring the technology forward to the point of implanting an NIRS sensor into a human spinal cord injury (SCI) patient.
 

Impact so far

We are still very early in our human testing, and from our first patient have identified the need for sensor refinement and further safety/performance testing (which this award is helping us to conduct).
 

Potential influence

We will ultimately change how the hemodynamic management of acute SCI is conducted.
 

Next steps

Right now, the most pressing issue is to get our newly refined sensors (arriving soon) and then conduct further safety/performance testing.

The acute impact of spinal cord injury on cardiac function, and novel hemodynamic management in SCI patients

Following acute spinal cord injury (SCI), one of the only presently available neuroprotective strategies is to try and optimize management of spinal cord blood flow. This treatment specifically aims to immediately increase blood flow to the injured spinal cord tissue to prevent the spread of injury to surrounding spinal cord tissues.
Currently, vasopressors are administered to increase blood pressure to a similar threshold in all patients; however, its efficacy in improving neurological outcomes has not been consistent, and in some patients has been found to actually worsen outcomes. A more optimized and individualized approach to blood flow management in SCI patients is needed.

High-thoracic SCI immediately impairs the brainstem and neural control of the heart. Our pilot data suggest this decentralization of the heart immediately impairs cardiac function, which could have significant implications for the acute management of blood flow in SCI patients. Dr. Williams will investigate the immediate and acute cardiac responses to high-thoracic SCI, and determine whether improvements to cardiac function can improve spinal cord blood flow and neurological outcomes in SCI patients.

Dr. Williams will conduct translational studies utilizing a porcine model of SCI. She will test the efficacy of potential novel management strategies, including restoring cardiac function alone or in combination with vasopressor therapy. A simultaneous study will look at acutely injured individuals with SCI at Vancouver General Hospital, examining heart function during the first three days after injury.

To date, very little work has characterized the impact of SCI on cardiac function in the initial period following injury. Combining invasive and integrative studies in pigs and humans provides us with the unique opportunity to conduct highly translatable studies that could have an immediate impact on SCI patient outcomes.

 

End of Award Update – July 2022

Most exciting outputs
Our research to date has identified how high-level spinal cord injuries (i.e. at or above the mid-back level) impact the heart immediately after the injury occurs. We found that those injuries impact the heart’s output within the first hours post-injury, and further identified a treatment that could harness the heart to support blood pressure and potentially reduce secondary damage to the spinal cord.

 

Impacts so far
The award has allowed us to examine alternative approaches to treating acute spinal cord injury which could ultimately improve outcomes if that approach is effective in the clinical setting. Moreover, as a trainee this award has provided the critical opportunity for me to expand my skillset in the realms of clinical and pre-clinical research, and apply gold-standard techniques to answer questions about the heart that have traditionally been overlooked in the field of spinal cord injury research.

 

Potential future influence
With the support of this award I have made significant strides in my training toward becoming an established cardiovascular researcher. First, it has allowed me to expand my expertise in the heart and its neural control. Second, I have gained invaluable experience in clinical and pre-clinical research, which truly round out my training as a physiologist. Finally, I have been able to produce and output impactful research across those domains and in doing so built strong collaborations with local and international leaders in these respective fields.

 

Next steps
We have yet to publish additional research that has stemmed from this award, looking at the long-term benefits of heart-focused approaches to treating spinal cord injury, and would like to pursue opportunities to implement such an approach in the clinical setting.

 

Useful links

Cardiac responses to spinal cord injury and exercise

The prognosis for the 2.5 million North Americans living with spinal cord injury (SCI) is poor. These wheelchair bound individuals are subjected to a number of physical, social, and environmental barriers that compound paralysis and limit daily physical activity. The five-fold increase in risk for heart disease reduces life-expectancy and costs the North American healthcare system $3 billion per annum.

Heart disease is the number one cause of illness and death in the SCI population. On a daily basis, these individuals are tasked with managing abnormal blood pressure control, fatigue, and a host of other bowel and bladder problems. Chronic management of these ‘secondary’ conditions can be poor, owing primarily to a lack of understanding of the underlying mechanisms. In able-bodied individuals, regular physical activity has multiple cardiovascular benefits. Although numerous attempts have been made to engage SCI individuals in regular physical activity, there is limited information available on the cardiovascular benefits of exercise in SCI individuals.

The primary aim of this research project is to investigate the effects of daily physical activity and structured exercise on heart function after SCI.

To improve our understanding of how the heart changes after SCI and the effectiveness of exercise, Dr. West will conduct simultaneous studies in rodents and humans with SCI. The use of a clinically relevant rodent model of SCI will allow Dr. West to answer fundamental questions about cardiac structure and function, and what mechanisms are responsible for the changes that occur after SCI and exercise. The findings will then be translated through conducting assessments of the heart in individuals with SCI.

This project is unique as it will be the first to use ultrasound to make identical measures of heart function in both rodents and humans. Additionally, Dr. West will be able to conduct direct assessments of heart function in the rodent model and follow this up with a detailed examination of the structure of the heart. Finally, he will conduct novel experiments into the effect of lower-limb passive cycling in rodents with SCI and follow this up by assessing how the heart responds to a novel passive leg energetic arm exercise intervention in humans.

Results from this study will yield vital information that can be used to assist in the rehabilitation and management of individuals with SCI.