Parkinson’s disease: visual initiation of movement

Flashing key-chain light that might be used to initiate movement in Parkinson’s disease. Photo: Mark Diamond

Flashing key-chain light that might be used to initiate movement in Parkinson’s disease. Photo: Mark Diamond

In his new book Always Looking Up, Michael J. Fox makes the following remark …

“It takes some form of outside stimulus, like the movement of an obstacle or, curiously, the introduction of an obstacle, for me to move forward. Some Parkies who freeze when walking can resume again when a ruler is placed in front of their feet and they are forced to step over it.”

When last I wrote about Parkinson’s disease, it was to suggest the use of an auditory signal as a way of assisting Parkinson’s sufferers to initiate their movements. I also commented that “a patient might, for example, wear a pair of spectacle frames containing coloured, light emitting diodes which pulsed in a way that was analogous to the tonal variations in an auditory stimulus.”

What I had in mind was something which would simply provide a pulsed visual stimulus, probably in the peripheral visual field; but the following might serve much better and be closer in conception to Michael J. Fox’s ruler.

A small, very bright LED or laser pointer directs one or more temporally and spatially separated spots of light onto the floor in front of the person whose movement is frozen. The light source could be attached to clothing or to a belt, or, perhaps most usefully, to a headband which would enable the ‘frozen’ person to direct the light in the direction the wanted to move. The temporal and spatial parameters of the pulsing of the light could be adjustable to suit the particular characteristics of each individual’s movements and if, for any individual, pulsing the light spots proved distracting or immobilising, the light could always be made continuous.

There are already key-chain (pulsable) lights on the market, available for as little as a few dollars, that could serve as a test-bed for the idea.

Contributors: Mark R. Diamond