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The combining of a central field cueing device with spectacles is offering patients with Parkinson’s disease (PD) a light for their path — literally — and enabling improved freedom.

The new device, referred to as Visual Cueing Spectacles (VCS), has been incorporated into spectacle prototypes by Enhanced Vision Systems under a licensing agreement from HMD Therapeutics for patients suffering from akinesia. Patients have to resort to techniques such as getting a push start, marching to a cadence, rocking the body, walking over objects and walking to music, just to “unfreeze.”

The spectacles create the phenomenon known as kinesia paradoxa, which allows patients to move more naturally by providing obstacles or an illusion of obstacles at their feet for them to step over.

In a study recently published by the Department of Veterans Administration, Journal of Rehabilitation Research and Development, VCS has been found to decrease the shuffling and freezing gait of PD patients suffering from akinesia.

VCS may be worn over their own prescription glasses and has been designed with a light-emitting diode display on one side that generates stationary horizontal lines of light on the ground in front of the patient, much like rungs on a ladder. As the patient raises their head slightly to look out ahead of their feet, the lines appear--giving the wearer a virtual walking surface or “step over” target as they walk forward. When they look straight ahead, the light display turns itself off but then reappears if participants’ heads tilt downward.

Visual cues for PD patients have been studied using other cues affixed to or projected on a surface, such as modified walking sticks and projected laser beam sticks and even VCS in laboratory environments. But the purpose of this small, but significant study was to determine the functional mobility using VCS in patient homes and around the community.

Lead author and primary researcher on the study, Tatiana Kaminsky, called the results “moderately successful.”

“This is not the first study that’s been done with them. It’s just the first study that was done in the community with them,” Kaminsky said. “Up until now, they were only tested in a laboratory environment. This study only had six participants, so you can’t say it was revolutionary, but it was encouraging. All of the participants said it was helpful to them. It didn’t necessarily stop the freezing, but it enabled them to get themselves out of it more easily.”

Kaminsky said she heard from study participants they felt more confident knowing if they get stuck they can get themselves out of it. Freezing gait also increases the risk for falls. It typically occurs about 10 years after onset of PD. Studies report prevalence of akinesia ranging from 32 to 60 percent among people with PD. It’s worse when patients feel stressed, pressured, or are in a doorway, elevator, or other narrow space.

“This was the first time these glasses had been taken out of a lab environment into the real world,” Kaminsky said. “It was small but it was the next phase of the study because people don’t live in labs. We wanted to know if the things we see in the lab carried over into the real world. There haven’t been any studies in the community because it’s very complicated. You can’t control things like you can in a lab.”

Tom Riess, former podiatrist and inventor of the spectacles — and a PD patient himself — said he came up with the idea when he developed a freezing and festinating gait.

“I first noticed that I didn’t have these problems while walking up or down stairs,” Riess said. “I discovered that there was something about the visual cadence of the stairs that was gait enabling. After much experimentation and observation, I realized the same effects could be obtained by using marks or cues on the floor--for example, (placing) playing cards spaced at stride length intervals and stepping over them like rungs of a ladder. Unfortunately, there are no playing cards on the floor in real life environments, so I wondered if these cues couldn’t be made portable, available on demand in a socially acceptable package (such as) glasses that would project these cues on the floor. I eventually hooked up with the Human Interface Technology Lab, a virtual reality research center, where we applied for and received an NIH grant to do a proof of concept study.”

Max Thomas, physical therapist and certified strength and conditioning specialist for Jackson Sports Medicine and Rehabilitation, said the spectacles make perfect sense and should make it easier for patients outside the physical therapy center.

“A big part of what we do with athletes is balance, agility training and coordinating training,” Thomas said. “The interesting thing is that if you take Parkinson’s patients through the same obstacle course, they typically start to look normal again. We literally will put down an agility ladder and have the patients walk through it. It’s really shocking that you put that ladder in front of them or different obstacles, medicine balls or whatever, and they’ll do them pretty easy, but have trouble without them. The same training carries over from athletes, whether a jet pilot or astronaut. The only difference is that with them, we’re taking them to a super level, and with PD patients, we’re trying to get them to function at a higher level of agility. That sounds like a great thing for them to use outside physical therapy.”

Lisa Indest, a physical therapist at Methodist Outpatient Rehabilitation, said she takes a different approach with PD patients.

“I haven’t heard of the spectacles, but we take patients outside and have them go up and down curbs and around things,” Indest said. “It’s not so much having the obstacles that do the work, but that training them using obstacles provides them with different types of functional activity needed when they are in a normal environment.”

Riess said he has licensed his patent to a company based in Newport Beach, Calif., Enhanced Vision Systems, which is currently developing a commercial version of the glasses.

“They send me the prototype periodically for testing and we are very close — maybe weeks — away from going into production,” Reiss said.



October 2007

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