Anxiety’s role in freezing of gait

Up to 80 percent of people with Parkinson’s disease will eventually experience freezing in place, a debilitating symptom precipitating falls and curbing people’s independence.

At the University of Waterloo, Assistant Professor Kaylena Ehgoetz Martens, a neuroscientist, studies whether anxiety helps cause or results from freezing of gait.

“Previously, a lot of my work focused on whether anxiety was an underlying factor that led the brain to jam because of all this information it was trying to process,” says Ehgoetz Martens.

Now, she wants to understand “whether anxiety lies at the core of all of freezing of gait episodes, or only in a select subset – in certain situations or in a certain subset of people.”

Working with people who have Parkinson’s, Ehgoetz Martens will show them pictures of environments that could cause freezing, as well as place them in virtual situations that could provoke freezing of gait. She’ll measure their movements, heart, and brain wave activity during these virtual reality exercises to determine the role anxiety plays.

“Ideally, at the end of this two years, we’re going to understand whether different subtypes of freezing of gait exist, and if people need different treatment strategies, we can make different recommendations.”

In one exercise, for example, people will “walk” across a virtual high plank versus a flat surface. Another virtual scenario would see them maneuvering across thresholds or around corners in an apartment.

“We expect that heart rate is going to increase prior to freezing of gait episodes, particularly in people who are highly anxious,” Ehgoetz Martens says.

If anxiety causes freezing of gait only in a sub-cohort of people, then heart rate should not increase in people who aren’t usually anxious, she says. If anxiety is at the core of freezing of gait, however, then heart rate should increase in everyone before all freezing of gait episodes.

In the final level of the project, people will stay for 24 hours in an apartment at the Schlegel-UW Research Institute for Aging. There they will be equipped with wearable smart technology to measure and eventually predict their responses to environments that could trigger freezing.

Working with colleagues in engineering, Ehgoetz Martens hopes eventually to create algorithms that predict freezing episodes, and ultimately design ways to interrupt or circumvent freezing.

“Ideally, at the end of this two years, we’re going to understand whether different subtypes of freezing of gait exist, and if people need different treatment strategies, we can make different recommendations,” she says.

Ehgoetz Martens has been interested in anxiety’s role in freezing of gait for 15 years, ever since she began volunteering with a woman whose severe freezing of gait derailed her rehabilitation progress.

At the time, there was scant research to suggest stress or anxiety was related to freezing at all, Ehgoetz Martens says. She ended up dedicating her PhD to exploring whether anxiety was a causal factor.

Ehgoetz Martens hopes her work will result in the use of mindfulness or other cognitive strategies to help people reduce or avoid freezing of gait, one of the most troubling symptoms of Parkinson’s disease.