Sandra Hundza

Sandra Hundza
Associate Professor
School of Exercise Science, Physical and Health Education

Research areas: Neural control of human movement; motor rehabilitation after injurywith disease and aging. Neural coordination of limbs and trunk during rhythmic movement and implications for balance control during walking; assistive technologies for those with disability

If you want to teach someone to walk, it helps to know how muscles are coordinated in rhythmic movement

Neuroscientist Dr. Sandra Hundza explores ways to teach people to walk again after a neurotrauma like a stroke or spinal cord injury, based on understanding the neural patterns that control rhythmic movement.

Dr. Sandra Hundza was drawn to neuroscience because of her experience as a physiotherapist, helping people learn to walk again after neurotrauma like stroke or spinal cord injury. During this clinical work, Hundza found herself wondering how you could improve therapies based on a more thorough understanding of what was going on between the brain, spine and limb muscles.

For instance, she noticed that if she gave a patient specific instructions on how to move an arm or leg during walking, patients often couldn't access the right set of muscles. However, if those same patients picked up the cadence of their walking, they often would automatically activate the appropriate muscles without thinking about it. It was if they were switching over to an automated neural control mechanism. Hundza wanted to further explore how these two modes of movement were controlled.

It was a natural fit, therefore, when Hundza chose to do a PhD under CBR director Dr. E. Paul Zehr, who studies the control of rhythmic movement like walking, cycling and swimming. Among other discoveries, Hundza helped Zehr show that rhythmic movement of the arms may influence people's ability to walk because of the way arms and legs are linked through neural networks during rhythmic motion (see CBR profile: The Leg Bone is Connected to the Arm Bone). She then went on to become an assistant professor in the same department, UVic's School of Exercise Science, Physical & Health Education, as well become an adjunct professor with the Island Medical Program.

Hundza's work remains complementary to Zehr's and to her initial questions from her clinical work. She specializes in studying the neural control of rhythmic movement, most specifically walking and balance control during walking, as well as what types of changes occur to this neural control as people age or after a neural or orthopedic trauma.

For instance, some of her current work is looking at tailoring common treadmill training programs for people learning to walk. In this therapy, part of a patient’s body weight is often relieved through an overhead harness. The idea is that if a patient can practice the motions of walking (even before they are able balance or stand up unassisted) they will strengthen the neural pathways needed for walking. Hundza wants to determine if there is an ideal level of body weight support or ideal cadence of walking to best re-train the neural pathways producing this automated rhythmic motion.

Hundza recently showed that as a person increases the cadence of rhythmic arm movement, the neural communication between arms and legs increases, resulting in a tighter link between the limbs. "You can see this yourself," she describes. "When you walk, you can easily keep your arms still if you want to. But as you go faster and begin to run, it gets harder. Part of this communication might be biomechanical, but part is neurological." She also found that an increase in the loading of the limbs does not affect the communication between arms and legs like the cadence of the movement. These results may suggest that during treadmill training physiotherapists should pay more attention to speed of the walking, rather than the level of weight that patients bear through their limbs.

To study these questions, Hundza probes neural pathways by electrically stimulating nerves to evoke reflexes and measures the muscle activation in the arms and the legs with electromyography. Basically, this is like when a doctor tests a reflex with a hammer, only instead of tapping a muscle, she stimulates it electrically. This method of measuring reflexes serves as a window into the function of the nervous system during motion. More specifically, it can tell Hundza about central pattern generators, which are networks of neurons that generate simple locomotor rhythm. For some of this research, she is collaborating with Dr. Tania Lam at UBC and with Zehr.

In the future, Hundza plans to look at role of trunk muscles and limb girdle muscles and how they are activated during rhythmic locomotion and their contribution to balance control during locomotion.

Her goal for all of her work is to provide the scientific ground work and data to develop new rehabilitation therapies based on a thorough understanding of how the nervous system controls walking and balance during walking in humans.

Dr. Sandra Hundza joins CanAssist to develop assistive devices based on detecting weak muscle movements

UVic's well-known CanAssist program has enjoyed incredible success over the past few years by creating assistive devices and technologies that improve the lives of people with special needs. One key reason for this success is that the program invites a multidisciplinary team of UVic professors, students, staff, and community volunteers to tackle a specific need for someone in the community.

UVic's neuroscientist Dr. Sandra Hundza joined CanAssist to help people by drawing on her clinical experience as a physiotherapist as well as her research on the neural control of movement. She is currently working on a CanAssist project to customize the use of electromyography (EMG) for several CanAssist clients.

EMG is a technique used to record muscle activation. EMG signals can be used to control many devices like a prosthetic limb or to activate a switch. For example an EMG signal from a forehead muscle can be used to activate a mouse click for a computer. An EMG signal can also indicate when a person is activating a muscle even when that muscle is too weak to move a limb.

Hundza is refining this technique by trying different muscles than the ones commonly used, such as forehead muscles. Some people do not wish to wear the headband needed to detect forehead muscle activity, or they find those muscles get easily fatigued, explains Hundza.

Hundza and other CanAssist team members are also working on the next-generation EMG controlled devices by exploring the possibility of getting more information out an EMG signal. By looking at different parameters of an EMG signal, Hundza believes they can differentiate between subtle muscle movements, expanding a person's movement repertoire to control devices.