Laser Shoes Alleviate Gait Freezing in Parkinson’s Disease

Researchers at the University of Twente (UT; Enschede, The Netherlands) and Radboud University Medical Centre (Nijmegen, the Netherlands) conducted a study to test the new ambulatory visual cueing device on 21 patients with PD and freezing of gait (FOG) in a controlled laboratory. The researchers measured the number of FOG episodes and the percent time frozen occurring during a standardized walking protocol. Participants performed 10 trials with the shoes turned off and 10 trials with cueing. FOG was assessed using offline video analysis by an independent rater.

The results showed that cueing using the laser shoes was associated with a significant reduction in the number of FOG episodes, both with (45.9%) and without (37.7%) medication. Moreover, the laser shoes reduced the percent of time spent frozen by 56.5% when the patients were off medication; reduction while taking medication was slightly smaller (51.4%). While the effects mirrored the patients' subjective experience on the laser shoes' efficacy, there were no clinically meaningful changes in gait measures. The study was published on December 20, 2017, in Neurology.

“Our tests were administered in a controlled lab setting with and without medication. Of the 19 patients who tested the shoes, the majority would be happy to use them. The patients did not seem to mind that the laser was activated for each single step,” said senior author neuroscientist Murielle Ferraye, PhD, who developed the shoes. “Ideally, the laser should only be activated once the blockage is detected, but we're not quite there yet; freezing is a very complex phenomenon.”

Walking problems are common and very disabling in Parkinson’s disease; in particular, FOG is a severe symptom which generally develops in more advanced stages. It can last seconds to minutes, and is generally triggered by the stress of an unfamiliar environment or when medication wears off. Because the foot remains glued to the floor but the upper body continues moving forward, it can cause the person to lose balance and fall.

But PD patients also experience a unique phenomenon; by consciously looking at objects on the floor--such as the lines from a zebra crossing--and stepping over them, they are able to overcome FOG. With the laser shoes, these useful visual cues can be continuously applied in everyday life to walk better and safer. The principle behind the laser shoes is simple: upon foot contact, the left shoe projects a line on the floor in front of the right foot. The patient steps over or towards the line, which activates the laser on the right shoe, and so on (see video).

Related Links:
University of Twente
Radboud University Medical Centre