The Rick Hansen Foundation reported 86,000 people in Canada living with a spinal cord injury. Ashley Dalrymple, who hails from Wetaskiwin, is a student at the University of Alberta conducting research to help patients struggling with such injuries.
Dalrymple is a masters of science student based in the Faculty of Medicine and Dentistry and holds an undergraduate degree from the U of A in electrical biomedical engineering. Soon she will be transferring to a PhD program to continue her work. Her current research project uses a technology invented by the university lab she is working in, called intraspinal microstimulation (ISMS).
She and her fellow researchers implant microwires into the area of the spinal cord that goes to the leg muscles. The researchers are then able to activate these muscles by using very small electrical currents.
“The gist of the research is … below the injury, the spinal cord is still intact and it can still make connections with muscles. It’s just the brain isn’t able to communicate,” explained Dalrymple.
“The technology we’re developing is kind of like a substitution for the brain. Instead of the brain telling the spinal cord to tell the muscles to work, we’re telling the spinal cord to tell the muscles what to do through electrical stimulation.
“It’s a very natural way that the nervous system works, through electricity.”
Data is collected using different sensors placed around the body to record things like muscle activity, force production, and limb position and from there researchers can figure out information about the limb itself, such as where it is in space, how well it’s doing in producing body weight supporting forces.
“The muscle activity kind of gives us an idea of the intent to move,” said Dalrymple.
“For example, if you record from your hip muscles, you might record some activity there but there’s no movement and it could be that the brain is trying to tell the limb to ‘pick up’ but it’s just not functional enough to actually produce the movement.
“So we’ll provide the stimulation to the spinal cord to kind of augment that intention.”
For her part in the project, Dalrymple is writing the computer programs that control the patterns of stimulation to achieve walking.
“In each part of the walking cycle, you have different muscles active at different times, so you have to be providing stimulation you gotta have the most natural patter of muscles being activated,” said Dalrymple.
“I’m writing all the programs to control the stimulation based on different sensors. Eventually, with the machine learning and using very intelligent systems, it will be automatically adaptable to different injuries.”
The project focuses on incomplete spinal injuries, which allows for some communication from brain to muscle but it’s not enough to be functional, whereas a complete spinal cord injury sees no communication from the brain to the muscles.
“The trick with all the stuff that I’m developing is trying to work with the remaining function instead of completely replacing it,” said Dalrymple.
“Hopefully in the end, once you get people with an incomplete spinal injury up and walking again, you actually can produce some improvements, like restoring some connections that were lost due to the injury.”
She is hopeful that the research will have rehabilitative application as well.
“If we can get walking again, we’re going to produce movements to improve overall health,” said Dalrymple.
“There’s a lot of health benefits just from being upright and metabolic benefits just from walking and moving.
“We’re also trying to reinforce partial connections or weak connections in the spinal cord to maybe improve the movements over time. We’re trying to make it adaptable, to work with the body … but also try to improve the natural way that the body is working with the natural connections.”
For now, the work is focused on incomplete spinal injuries, but moving forward it may also be extendable to people with other injuries or diseases, including stroke and multiple sclerosis.
“The intended use right now is spinal cord injury because it’s easier model and it doesn’t deal with the brain at all, just spinal cord,” said Dalrymple.
“With the adaptability that I’m going to be building into the system, it could for sure be used to treat stroke, like severely impaired stroke patients that can’t walk.”
Sarah O. Swenson