Pedal power! | Action Medical Research

Touching Lives - March 2004

Pedal power!

Exercise can be an important therapy for some spinal injury and stroke patients — and may even contribute to their recovery. But if you have lost the use of your limbs due to illness or accident, taking regular exercise isn’t easy.

A study undertaken by a team at University College London has unearthed some exciting results that could have implications for the treatment and rehabilitation of the 100,000 people in the UK who suffer disability following stroke or spinal cord injury each year.

Dr Nick Donaldson heads the team who recently completed a six-month Action Medical Research study to test the effectiveness of a special exercise treatment where electronic pulses are applied to patients’ legs.

Muscle stimulation

Muscle stimulation is nothing new of course — ‘Superman’ actor Christopher Reeve is perhaps the best known patient trying muscle stimulation technology to regain mobility — but rather than rely on electrical impulse alone, the UCL team has tried to identify how much voluntary effort the patient is using in pushing a pedal during cycling exercise.

It is a difficult measurement to obtain, but identifying this voluntary effort is important, because the team hopes that a combination of voluntary movement, enhanced by electrical muscle stimulation, holds the key to new treatments and more effective therapy.

Electromyography (EMG) is a way of electrically recording muscle activity. A team of volunteers — six able-bodied and one patient with incomplete spinal injury — ‘cycled’ in the laboratory while the recordings were taken. The team could now compare EMG signals from muscles with and without stimulation.

Dr Donaldson said, “We were unsure of what we would find, but have been pleasantly surprised. We get a high correlation between the two sets of data when we measure one tenth of a second after giving the stimulation pulse.

“This data suggests that we can assess the level of voluntary effort despite the stimulation. We will have to design a stimulator that produces pulses with irregular intervals, rather than a steady frequency, and the intensity will depend on this voluntary effort from the patient. This would lead to the development of a special tricycle where the leg muscles are stimulated only if the patient makes a voluntary effort to turn the pedals.

Early days

“It’s very early days, but now that we know how to measure the voluntary effort, we have passed a major hurdle.

“Of course every stroke victim and every spinal injury patient has different needs,” Dr Donaldson continued, “but by measuring the level of muscle amplification needed we can develop equipment that can be used at home and that could play a major role in providing exercise and treatment for these groups.”

The team is now discussing the next stage in their study — embarking on any sort of clinical trial is a very big undertaking.

Dr Donaldson said: “The results of the six month study have been very encouraging. For the first time we can see how much voluntary effort a paralysed patient is making and this knowledge may be the key to better therapy, leading to increased functional recovery after the stroke or spinal cord injury.”

Grateful thanks go to SEARCH for their support of this grant.

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