Brain imaging identifies ways to help stroke patients regain speech

6 June 2008

An important breakthrough in understanding how the brain works could help stroke patients to regain their speech. The UK charity Action Medical Research has announced the results of the study as a "leap forward in understanding".

The charity says that patients could benefit from this discovery within the next three to five years.  Up to one quarter of stroke patients suffer from speech impairment of some degree. This can mean difficulty with speaking and understanding what is said to them or even trouble with reading and writing.

Some people find that, over time, their speech and understanding improves but many more face an uphill struggle and some never recover; even with therapy. Until now little was known about why some patients make progress and some do not.

However, the Action Medical Research study has found that an answer lies in the complex pathways that exist between the speech processing areas on both sides of the brain.

Dr Jane Warren, who is based at Imperial College London, has used specialised brain imaging techniques to identify areas of the brain that are responsible for understanding speech and their connections with each other. She has compared the way that nerve cells function in healthy brains with those in patients who have been affected by stroke.

She has discovered that the brains of stroke sufferers may have to 'relearn' how to put together different types of information in order to understand speech by using different parts of the brain to compensate for damaged areas.

This may mean using new pathways so that one side of the brain can talk to the other more effectively. Therefore, the better that these two sides of the brain can co-operate then the better the chance of speech recovery for the patient.

This breakthrough could assist the development of new drug and therapy-based treatments to help patients to learn to speak again.  Dr Yolande Harley of Action Medical Research said, "This really is a leap forward in understanding and is likely to be of benefit to patients in the near future.

"Language difficulties can have a devastating, long term effect well after someone has recovered from the shock and immediate physical impact of having a stroke. Simple, everyday activities that we take for granted; making a phone call, doing the shopping or simply holding a conversation can become an ordeal.

"We all have those moments where a word is on the tip of our tongue and know that frustration; imagine constantly feeling as if you are struggling to find a word and that you cannot get across exactly what you want to say. Then you may get a sense of the distress that a stroke patient feels."

Dr Warren explains, "We've known for a long time that different parts of the brain do different things; but one aspect of the brain that we knew little about is how the brain creates and uses language systems.

"During the course of my work I have been able to find out what is happening within the brain as stroke sufferers recover their speech. Researchers already know that the front left hand side of the temporal lobe seems to be concerned with finding meaning whilst the right hand side is more concerned with inflection or pitch.

"When a stroke occurs, the blood supply to part of the brain is blocked and, as a result, it doesn't get any oxygen or nutrients and dies. My work has shown that the brain has a remarkable range of alternative strategies to bypass these dead areas and resume normal service.

"There are several circuits that link different parts of the brain together. Whether or not these circuits are damaged by a stroke is likely to be a big factor in determining how well a stroke sufferer recovers language.

"If we can find ways to get the left and right sides of the brain co-operating with one another better after a stroke, we could improve the chances of recovery. It's a very exciting result."  

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