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

Can rhythm help people with Parkinson’s disease

This is a proposal for a series of research studies related to a device for assisting people with Parkinson’s disease. For some background, have a look at the description of the device.

An interesting and informative research project could be conceived on a fairly small scale, and enlarged as time went by and more data accrued. I can imagine that the first stage of the research would suit an honours project in human movement, occupational therapy, bioengineering or psychology.

First, discover whether auditory pulses can assist those people who have difficulty in initiating voluntary movement. I have mentioned people with Parkinson’s disease, but there are other groups of people with similar difficulties. The first experiment would probably need no more equipment than a sound generator for producing a pulsed tone, and perhaps a method of enhancing the rhythmic quality of the sound (either by changes in volume, pitch, or timbre). Even if the method does not help all patients, is it capable of helping some of them.

The second stage might be an exploration of different sorts of stimulus (auditory, visual, tactile) to determine whether some sensory modalities worked better than others, and to discover the kinds of changes in each (e.g., amount of pressure in the case of tactile stimuli, or colour changes in the case of visual stimuli) that worked best as an indicator of rhythm.

Later experiments might explore the extent to which stimuli could be optimized for individual patients, whether different stimuli were maximally effective for different movements (walking, washing, chewing, etc.), the production of a small programmable device, and the inclusion of voice activation of the different stimulus combinations.

Contributors: Mark R. Diamond