Freezing of gait is one of the most frustrating symptoms of Parkinson's Disease.
It is the sudden inability to take a step despite the intention to walk. Although there are several triggers, it often occurs when a person moves from one environment to another — for example, moving from one room to the next, getting up from a chair to walk, or getting on or off an elevator. During an episode of freezing of gait (FOG), the person's feet refuse to step forward. However, their upper body’s momentum continues forward, causing that person to fall.
What causes Freezing of gait and how can it be handled?
Freezing of gait in people with Parkinson’s is caused by a disconnect between the brain and the body causing the signal to walk to not get to the motor neurons that activate the muscles. Parkinson’s disease kills the cells in an area of the brain known as the substantia nigra. This section of the brain produces dopamine, the neurotransmitter essential to the control of movement. In the absence of brain cells, dopamine levels drop, resulting in mismatched and slow movements, tremors, and shaking.
External cues such as audio, visual, or touch help trick the brain into walking forward. These cues bypass the damaged neural pathway that is causing freezing, and allow you to use a different neural pathway to activate movement.
Over the years, people with Parkinson’s have used various methods to trick their brains into stepping forward. Some people find it helpful to focus on a floor pattern. One person even etched a line across his glasses, so when he looked down, he could see the line and begin walking. While the idea was helpful, it also obstructed his vision.
Another visual cue that people have found helpful is a beam of light. The downside to this technique is that it isn't conducive in a brightly lit place, and the beam from a flashlight spreads out too far, making it difficult for a person with Parkinson’s to focus.
The most helpful visual cue has been a laser beam or pointer, as the laser’s concentrated beam of light can be seen clearly and can be used as a goal to step over to overcome freezing of gait episodes.
What is a laser and how does it address freezing?
Laser stands for Light Amplification by Simulated Emission of Radiation. The light from a laser is tuned to a specific wavelength, making it a focussed and powerful beam.
The laser was invented in 1958 and is used across a variety of different industries, with some Laser beams being so intense that they can cut through steel and shape diamonds.
The NexStride, a portable mobility device, uses green laser light as a visual cue to overcome freezing of gait. The NexStride's laser acts as a goal (sort of like a finish line at the end of a race). The laser appears as a straight line in front of the person, providing a visual trigger to step towards the line.
The green laser is in the NexStride mobility aid that attaches to the walker, walking poles or cane, faces downwards (away from the user), and when turned on, the light is projected at the floor or ground in front of the user. The user visualizes themselves stepping over that line, and by adding that goal you change the way the brain activates that movement.
In the video below, you can see how the laser helps with the Freezing of Gait.
The NexStride uses audio and visual cues to help people with PD deal with episodes of freezing. The device also uses an in-built metronome to provide an audio alert, while the laser provides the visual signal. The downward-facing laser projects a green light on the floor, with an adjustable location. The mobility device is mounted on the person's cane, walker, or walking poles.
Is the laser harmful? What precautions should I take?
Lasers are widely used across many devices, technologies, and equipment. While the green laser provides much-needed relief to a person grappling with freezing of gait, it is advisable to use these devices with care.
DO NOT look directly at the laser's source as it can cause severe eye damage if you’re close enough to the laser. Please turn off the laser when not in use.