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Research in motion

Mike Fahning’s freezing of gait may literally stop
him in his tracks up to eight times a day, but he never
freezes while he is biking—a freeing activity for him
and many others who have Parkinson’s disease. (Photo: Scott Streble)

U scientists explore freezing of gait, a debilitating complication of Parkinson’s disease, and actions that can get patients moving again

Up until about four years ago, Mike Fahning thought of his Parkinson’s disease as an irritant. His medications seemed to be managing the involuntary movements that are a hallmark of the disease, with which he was diagnosed at age 38.

But one Sunday afternoon in 2010, Fahning was at home doing housework when suddenly he couldn’t move. His medications, which he has to take every few hours, had worn off, and he was stuck.

“It was literally like having cement shoes,” he recalls. “I was really frustrated. I had this laundry basket on the ground, and I started kicking it down the hall. As I kicked this laundry basket with my feet, it prompted me to walk. It was a really weird deal.”

Fahning brushed off the incident, until he went to his job as chief financial officer of an auto dealership the next day and it happened again—in the middle of the busy dealership’s showroom. So he did the only thing he could think of. He set down the soda bottle he was holding and kicked it toward his office.

“It prompted me to walk,” he says. “It was just bizarre.”

Though Fahning wasn’t familiar with the term at the time, he was experiencing “freezing of gait,” a complication of Parkinson’s disease that is simply described as a temporary and involuntary inability to move. It can happen any time but most commonly occurs when a person is changing directions or walking through a cluttered room or narrow space like a doorway. Because the start and end of a freezing episode are unpredictable, falling becomes a risk, too.

“About 70 percent of people with advanced Parkinson’s disease will have freezing,” says Colum MacKinnon, Ph.D., a movement disorders researcher and an assistant professor of neurology in the University of Minnesota Medical School. “If you ask them what their number-one problem with quality of life is, they’ll tell you it’s issues with their mobility. It’s a big deal for these patients.”

Understanding cues

The freezing phenomenon is not well understood. Nor is it understood why certain actions, or “cues,” can put an end to a freezing episode.

For Fahning, kicking an object can often get him moving again. (His three sons even rigged up a tennis ball on a rope that he often carries around in his pocket in case he gets stuck when no one is around to help him.) Stepping on to a new tile on a tile floor or aiming a laser pointer on the floor in front of him can also help. Other cues that can work to “unfreeze” people who have Parkinson’s disease include a tap on the shoulder, a countdown (3-2-1-go), or watching a clock (planning to take a step when the second hand reaches 12, for instance), MacKinnon says.

The University’s Colum MacKinnon, Ph.D. (center), with research partners Jackie Vachon, M.S., and Chiahao Lu, Ph.D., record muscle and brain activity in their lab. They hope to learn what’s going on in the brains of people who have Parkinson’s as they prepare to move and then actually move. (Photo: Scott Streble)

But cues don’t always work, and they seem to work best when the stimulus is coming from another person or a machine rather than from the person with Parkinson’s. “No one really knows what’s going on in the brain that makes that happen,” MacKinnon says.

That’s why he and his colleagues are investigating the most effective ways to use cues and how clinicians and caregivers should present cues to most reliably overcome freezing episodes. A subsequent series of experiments will examine the brain physiology behind freezing and why cueing works. These studies are funded by the National Institutes of Health.

The group’s current research involves measuring movement with high-speed cameras and recording muscle and brain activity of people with Parkinson’s disease and healthy people as a comparison as they prepare to move and then when they actually move. They’re studying the timing and intensity of auditory cues, visual cues, and vibrotactile cues (such as the buzz of a vibrating phone) to help figure out how clinicians should teach patients to use them.

These experiments will help to answer two important questions: Which paradigms let people who have freezing episodes best prepare to move? And why do they work?

‘Something significant’

It’s only through understanding the problem that solutions may be found.

“Dr. MacKinnon is focusing on an aspect of Parkinson’s disease that brings great disability but has not received much attention,” says University of Minnesota neurologist Paul Tuite, M.D. “His research strives to provide technical insight into understanding freezing and, therefore, may yield treatments. As clinicians, we have little to offer [today] in ameliorating this problem.”

Department of Neurology chair Jerrold Vitek, M.D., Ph.D., believes MacKinnon’s work stands to make a real difference in how people who have Parkinson’s address their gait freezing. “I am convinced his work will greatly benefit patient care in the future,” Vitek says.

And that’s music to Fahning’s ears. He deals with freezing episodes up to eight times a day as his medications wear off. And sometimes they happen at inopportune times, like this past winter when he crossed his dark street in the evening to get his mail and got stuck outside for 20 minutes.

Fahning, 50, was one of the first in line to participate in MacKinnon’s research studies. Now he’s encouraging others to join him to help advance knowledge about Parkinson’s disease.

“A great mentor of mine said, ‘Mike, it doesn’t matter what you do in life, but try to do something significant,’” Fahning says. “I’m not sure what that’s going to be, but if being a part of a clinical study can help me feel like I’m a part of something, whether it’s today or whether it’s down the road, that’s what I want to do.”

To learn more or make a gift to this research, contact Tracy Ketchem of the University of Minnesota Foundation at 612-625-1906 or

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