RECOVERY following a stroke can be difficult, but a new study gives an insight into potential recovery markers and new treatment options.
If a stroke occurs in the left hemisphere of the brain it is likely to affect language and speech-motor regions. One result of damaging these areas is aphasia, characterised by difficulties in speaking, naming, repeating, and understanding language. Many people undertake successful speech therapy, however, even intensive speech therapy does not guarantee a full recovery.
The study included 33 people who have been affected by a stroke in the left hemisphere within the last 2.5 years (average age of 58 years), and 13 healthy controls of a similar age who had never had a stroke. Aphasia of varying degrees of severity was observed in all those who had had a stroke. The participants in the study underwent a magnetic resonance imaging (MRI) scan of the brain, which using a special technique, focussed on tissue integrity and connectivity in various areas.
The MRI revealed that patients who performed better on speech-fluency tests were more likely to have higher structural integrity, in some areas, than the healthy controls, with better structural integrity potentially indicating more connectivity. Three areas stood out in particular: the right middle temporal gyrus, the right inferior frontal gyrus, and the right precentral gyrus. The analysis showed that there was a large contribution to speech-fluency from the right hemisphere, as including the right hemisphere information improved the correlation between connectivity and speech-fluency. This suggests there may be some reorganisation in the right hemisphere to account for injury to the left hemisphere.
Dr Anna Barrett, Director of Stroke Rehabilitation Research, Kessler Foundation, West Orange, New Jersey, USA, commented that: “This study suggests that a well-wired right brain actively supports recovery from aphasia.” Dr Barrett added that although further research exploring the cause of differences in structural integrity are needed, it may be possible to develop new therapeutic targets in the right brain for people with aphasia.
In this vein, study author, Dr Gottfried Schlaug, Associate Professor, Harvard Medical School, Boston, Massachusetts, USA, suggested that melodic intonation therapy may be a good therapeutic method as it is a targeted towards the right hemisphere.