Brain Advance Access originally published online on March 18, 2008
Brain 2008 131(5):1391-1401; doi:10.1093/brain/awn043
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Association between therapy outcome and right-hemispheric activation in chronic aphasia
Department of Biological and Clinical Psychology, Friedrich Schiller University; Am Steiger 3/1; D-07743 Jena, Germany
Correspondence to: Thomas Straube, PhD, Department of Biological and Clinical Psychology, Friedrich Schiller University, Am Steiger 3/1; D-07743 Jena, Germany E-mail: straube{at}biopsy.uni-jena.de
The role of the right hemisphere for language processing and successful therapeutic interventions in aphasic patients is a matter of debate. This study explored brain activation in right-hemispheric areas and left-hemispheric perilesional areas in response to language tasks in chronic non-fluent aphasic patients before and after constraint-induced aphasia therapy (CIAT). In particular, we analysed the relation between brain responses and therapy outcome. Using functional magnetic resonance imaging (fMRI), brain activation was measured during word-reading (REA) and word-stem completion (COM) in 16 chronic non-fluent aphasic and 8 healthy subjects. Before therapy, activation in right inferior frontal gyrus/insula (IFG/IC) was stronger in aphasics compared to controls during REA and in precentral gyrus (PCG) during COM. Therapeutic intervention per se did not change brain activation for either task across all aphasic subjects. However, therapeutic success correlated with a relative decrease of activation in right-hemispheric areas, including the IFG/IC. Most importantly, initial activation in right IFG/IC and other right-hemispheric areas correlated positively with subsequent therapy success. Thus, right-hemispheric activation prior to aphasia therapy strongly predicts therapeutic success, suggesting that brain activation in chronic aphasia indicates the patients potential for further language improvement.
Key Words: aphasia; recovery; CI aphasia therapy; right hemisphere; functional MRI
Abbreviations: AAT, Aachen Aphasia test; BI, behavioural improvement; CIAT, constraint-induced aphasia therapy; fMRI, functional magnetic resonance imaging
Received October 4, 2007. Revised January 25, 2008. Accepted February 21, 2008.