Brain reorganisation: moving towards recovery after stroke

Caring for stroke sufferers Transcranial stimulation

Dr Nick Ward, Dr Jennie Newton, Dr Jon Marsden, Ms Gita Ramdharry, Professor John Rothwell, Dr Richard Greenwood, Dr Orlando Swayne, Dr Penelope Talelli, Dr Brian Day and Dr Binith Cheeran.
University College London.

How do patients recover from paralysis after stroke, the leading cause of long- term disability worldwide? New methods for speeding recovery will have an  enormous impact for the individuals involved and for the costs of providing long-term therapy, support and care. Techniques that allow the study of the working human brain show that reorganisation in undamaged parts of the brain may be the answer.

Nick Ward and his colleagues at the Institute of Neurology, University College London, use functional magnetic resonance imaging (fMRI) and transcranial magnetic stimulation (TMS) to explore how the brain reorganises to regain mobility in stroke patients. 'If we can find a means of prompting or speeding up this process we could potentially have an effective treatment', explains Nick.

Nick and his colleagues are one of a few teams worldwide taking this approach to stroke. 'Rather than trying to fix damaged areas we are looking for a way around it, by identifying how other parts of the brain take over'.

fMRI allows a person's brain to be scanned for activity whilst they perform a task, such as gripping an object. To see which parts of the brain are compensating for stroke damage, comparisons can be made between the areas of brain activity in normal subjects and stroke patients. Stroke patients can also be scanned over time to see how areas of brain activity change as they regain mobility.

With TMS, a magnetic field, created by a current running through a hand-held coil, is used to stimulate the brain. When held close to the skull the coil makes clicking noises, felt like 'taps'. The magnetic field creates electrical signals in the brain that are routed down the spinal cord to move particular muscles that visibly twitch. The level of stimulus needed, the time taken for a twitch and the power of the twitch itself, all indicate how intact the body's system is for controlling movement.