fMRI Investigations of Recovery in Stroke Patients

fMRI is being used to investigate the mechanisms and factors influencing recovery of stroke patients. Novel test methods are developed on healthy volunteers before using them on stroke patients.

We detect brain activity associated with movment and one of the major challenges of this project has been to develop a new type of movement that stroke patients can perform reliably. We have developed a test based on wrist movement, where previous tests have usually nvolved finger movement. This type of movement recovers before finger movements and requires a lot less effort for a patient recovering from a stroke. This has enabled testing of a wider range of recovering stroke patients than previous studies.

Initial investigations have supported well-known theories about the recovery of stroke patients, in a wider range of cases. The results show that when a stroke sufferer receives damage to a motor cortex some movement can be regained, without the motor cortex recovering. The most successful recoveries seem to occur when the premotor cortex and/or the supplementary motor area take over the functions of the motor cortex. A more limited recovery is possible when the motor cortex on the healthy side of the brain takes over.

Our research is moving away from tests dependent on the patient's movement and towards tactile and attentional tests. These are new areas of research, which should prove more comfortable for the patients, and will examine different areas of recovery. Tactile tests will involve touch stimulation of patients. Attention can be studied on patients who are physically able to see but who cannot pay attention to objects in their field of vision.

Maps of brain activity acquired during a simple motor task for a stroke patient who recovered well.

Maps of brain activity acquired during a simple motor task for a stroke patient who recovered poorly.

Despite his lesions this patient shows a relatively normal pattern of activity, with movements of each hand associated with activation of the respective contralateral primary motor cortex.

Researchers

S Bethel and A Sunderland,
Division of Stroke Medicine

P Gowland, P Morris
Magnetic Resonance Centre

This work is funded by the Medical Research Council