Making strides

Researchers have developed a pair of glasses which could help some people with Parkinson’s disease to walk more normally by giving visual cues in the periphery of their vision.

Researchers have developed a pair of glasses which could help some people with Parkinson’s disease to walk more normally by giving visual cues in the periphery of their vision.

INDIGO glasses display scrolling cues to stimulate paradoxical kinesis

People with Parkinson’s typically have a slow, shuffling gait. By wearing the spectacles, called INDIGO – INDependent I Go – some are able to regain a more normal length of stride.

The INDIGO glasses display moving lines at the edge of the field of vision. They were developed by the ParkService initiative, a project which is co-funded by the European Commission’s eTEN programme.

Reynold Greenlaw, Senior Consultant with Oxford Computer Consultants and coordinator of ParkService said: ‘We have been involved since 2000, when we met a man with Parkinson’s who was interested in his reaction to certain visual cues.

‘When he lined up pieces of paper on the floor, he could stand up straighter and walk almost normally. We thought, “Wouldn’t it be great if he could see them everywhere he went?” We set up a European project called PARREHA to develop a tool which would do that.’

Through PARREHA, Greenlaw and his colleagues formulated a rough prototype using virtual reality and moving visual images. As the project progressed, they formed ParkAid, which now owns the intellectual property rights for INDIGO, to further development.

‘The INDIGO glasses we now have are what we call augmented reality – in other words blending virtual reality with reality,’ said Greenlaw.

The system consists of a pair of spectacles with an embedded monitor, a simple box of electronics, a microcomputer and batteries, which can be clipped to a belt.

‘In the original design, the user would wear the glasses and motion detectors would overlay the appearance of paper on the floor, detect the wearer’s movements and keep the image on the floor,’ said Greenlaw.

‘We found it was effective, and discovered that true motion tracking wasn’t required. Now we just have a display scrolling different cues. We can change the direction speed, colour and effects on the cues, allowing us to get the best results for each individual. We found that black and white stripes moving upwards are generally effective.’

Not every person with Parkinson’s reacts to the cues. Greenlaw suggests that people with Parkinson’s first try attending a clinic or asking a friend to observe them to see if they can walk better with paper laid on the floor, or going upstairs rather than across a room.

Neurologists cannot fully explain how the visual cues work to promote movement, but the phenomenon is known as paradoxical kinesis.

Parkinson’s is a neurological condition which affects the substantia nigra, a pigmented area in the brain. In people with Parkinson’s, the dopamine-producing cells in this area die, which in turn causes problems accessing motor routines, particularly ones such as walking, talking or swallowing.

In certain circumstances, if patients are stimulated externally, such as throwing a ball towards them, the motor routines can be triggered.

‘If there is an emergency, people with Parkinson’s can sometimes find the ability to walk normally, and there are even examples of people running out of burning buildings. They are not accessing motor functions through the normal routes,’ said Greenlaw. ‘The idea with INDIGO is to replicate those conditions and make the brain think that things are not normal.’

Professor Marjan Jahanshahi, a Clinical Neuropsychologist at the Institute of Neurology (ION), University College London, said: ‘Function imaging shows that the brain activity in a person with Parkinson’s when externally stimulated shows less difference from normal activity that when an action is self-initiated.’

Jahanshahi and her colleagues at ION are carrying out clinical trials sponsored by The Parkinson’s Disease Society to study whether wearing INDIGO glasses improves walking.

Jahanshahi said: ‘We will compare Parkinson’s patients under four conditions: wearing the glasses with the stimuli activated, wearing the glasses without active stimuli, with stationary lines on the floor and unaided. Through this we will establish whether the glasses give better results than just putting lines on the floor.’

The glasses have already been used in Germany by three people with Parkinson’s and have produced striking results.

‘We want to see the results on a larger group in a formal clinical trial,’ said Jahanshahi.

The trials are beginning now with a sample of 70 people with Parkinson’s and will last a year.

Currently two people in every thousand develop Parkinson’s disease, a figure which is likely to go up in the future with an aging population and as diagnosis improves. Parkinson’s progresses in five stages; if the trials are successful, INDIGO glasses could help relieve the symptoms for 10 per cent of people in stages two, three or four.

Video clips of INDIGO in action can be seen here.