Mon, 28 Jan 2013 08:44 UTC
Clinical researchers at Glasgow University are aiming to help patients overcome some of the physical disabilities caused by a stroke.
The team from the university's Institute of Cardiovascular and Medical Sciences will undertake the world's first in-human trial of vagus nerve stimulation in stroke patients.
Strokes, which affect 280 per 100,000 people in Scotland annually, can result in the loss of brain tissue and negatively affect various bodily functions from speech to movement, depending on the location of the stroke.
The study, which will be carried out at the Western Infirmary in Glasgow, will recruit 20 patients who suffered a stroke around six months ago and who have been left with poor arm function despite receiving the best available treatment.
Each participant will receive three one-hour sessions of intensive physiotherapy each week for six weeks to help improve their arm function.
Half of the group will also receive an implanted Vivistim device, a vagus nerve stimulator, which connects to the vagus nerve in the neck. When they are receiving physiotherapy to help improve their arm, the device will stimulate the nerve.
Lead researcher Dr Jesse Dawson, a stroke consultant and clinical senior lecturer in medicine, said: "It's a little bit like a cardiac pacemaker. It's a small device that sits under the skin in the chest, but instead of connecting to the heart, it connects to a nerve in the neck.
"That nerve is one of the major nerves that goes to the brain. By stimulating the nerves, you can cause upstream changes in the brain without having to go into the brain."
It is hoped that the device will stimulate release of the brain's own chemicals, called neurotransmitters, that will help the brain form new neural connections which might improve participants' arm mobility.
Dr Dawson added: "When the brain is damaged by stroke, important neural connections that control different parts of the body can be damaged which impairs function.
"Evidence from animal studies suggests that vagus nerve stimulation could cause the release of neurotransmitters which help facilitate neural plasticity and help people re-learn how to use their arms after stroke, particularly if stimulation is paired with specific tasks.
"A slightly different type of vagus nerve stimulation is already successfully used to manage conditions such as depression and epilepsy.
"This study is designed to provide evidence to support whether this is the case after stroke but our primary aim is to assess feasibility of vagus nerve stimulation after stroke."
The study is being sponsored by Dallas-based Microtransponder Inc, a medical device company that has developed the Vivistim device and has received substantial support for its work from the US National Institutes of Health. A similar study into vagus nerve stimulation for the treatment of tinnitus is also being explored.
The company approached Glasgow doctors because of the city's track record on stroke research and the success of the Pisces study (Pilot Investigation of Stem Cells in Stroke) led by Professor Keith Muir at the Institute of Neurological Sciences at Glasgow's Southern General Hospital.
Participants in that study, in which stem cells were implanted into damaged brain tissue, experienced better thumb and finger movement, better strength and stability in the legs and improved speech.
Dr Jesse Dawson has been involved for some time in research into the use of robotic devices on the rehabilitation of upper limb function after stroke.
He said: "It remains to be seen how much we can improve function, but if we can help people perform even small actions again, like being able to hold a cup of tea, it would greatly improve their quality of life."
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