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

Parkinson’s disease: initiating movement

Parkinson’s disease is a slow, debilitating, degenerative neurological disease which develops as a result of the death of cells in a part of the brain known as the substantia nigra. The disease is characterized by tremor, muscle rigidity, stiffness, difficulty in bending one’s arms or legs, a loss of balance, and changes in gait—including the development of a slow shuffling walk. People with Parkinson’s disease can experience extreme difficulty in initiating voluntary movements, sometimes to the extent that they might even appear “frozen” while they are struggling in the moments before they actually begin moving.

A great deal of research in recent years has focussed on ways in which the cells in the substantia nigra might be replaced, and many (if not most) of the patents relating to Parkinson’s disease focus on biological or pharmaceutical treatments. What is proposed here, however, is far simpler — an intervention that might possibly provide immediate help to those people who have difficulty with the initiation of movement. If the proposed device worked in the way intended, it would be unlikely to pose any manufacturing difficulties, and be of relatively low cost. But first a little background …

You might remember the film “Awakenings”, starring Robert De Niro and Robin Williams. The film was based on the experiences of Dr Oliver Sacks who had written a book with the same title. In one scene in the film, patients (who did not have Parkinson’s disease but nonetheless had difficulty with initiating voluntary movement) are shown being able to walk across a patterned floor more easily than they would have been able to negotiate a homogeneously tiled floor. The patients used some of the coloured tiles as stepping stones on which to pace out their steps. It was as if the pattern provided the patient with a method of timing their steps once they had been initiated, as well as with the initiation of movement.

In the proposed device, the person with Parkinson’s disease would listen to a sound whose tonal characteristics (including amongst other things, volume, loudness variation, pitch, pitch variation, rhythm, and rhythmic variation) were set so as to maximize the person’s ability to initiate a desired movement. A triple-beat tone, for example, sounded loud-soft-soft, or high-low-low, might aid the initiation and maintenance of movement in the same way that a musician calling out “ONE-two-three ONE-two-three ONE” indicates to his or her fellow musicians when they should commence playing.

The development of the device would proceed hand-in-hand with a series of small experimental studies, and if the device were found to be of any benefit, it could be enhanced in several obvious ways including the following.

  • Many different pre-programmed tonal mixtures each suited to a different movement.
  • Analysis of an individual patient’s movement pattern could provide the appropriate parameters for walking, washing, washing up, polishing and indeed any kind of movement one wished.
  • The appropriate sound could be activated in several different ways including activation by artificial voice-recognition of a spoken command, such as “walk”, or activation by pressing a button on the device.
  • Existing music tracks could be analyzed for their rhythmic qualities to determine which tracks would provide the appropriate sound for a particular movement. That way, the person would be able to choose to listen to music rather than to a boring sound.

Obviously, sound is not the only method by which the appropriate movement-initiating stimulus could be delivered. Tactile and visual stimuli could both be used and programmed for the same kinds of variations as described above. 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.

Contributors: Mark R. Diamond