Related resources
Full-text held externally
Search for item elsewhere
University researcher(s)
Academic department(s)
Joint Independent Component Analysis of structural and functional images reveals complex patterns of functional reorganisation in stroke aphasia
Specht K, Zahn R, Willmes K, Weis S, Holtel C, Krause B.J, Herzog H, Huber W
Neuroimage. 2009;.
Access to files
Full-text and supplementary files are not available from Manchester eScholar. Full-text is available externally using the following links:
Full-text held externally
Abstract
Previous functional activation studies in patients with aphasia have mostly relied on standard group comparisons of aphasic patients with healthy controls, which are biased towards regions showing the most consistent effects and disregard variability within groups. Groups of aphasic patients, however, show considerable variability with respect to lesion localization and extent. Here, we use a novel method, joint Independent Component Analysis (jICA), which allowed us to investigate abnormal patterns of functional activation with O15-PET during lexical decision in aphasic patients after middle cerebral artery stroke and to directly relate them to lesion information from structural MRI. Our results demonstrate that with jICA we could detect a network of compensatory increases in activity within bilateral anterior inferior temporal areas (BA20), which was not revealed by standard group comparisons. In addition, both types of analyses, jICA and group comparison, showed increased activity in the right posterior superior temporal gyrus in aphasic patients. Further, whereas standard analyses revealed no decreases in activation, jICA identified that left perisylvian lesions were associated with decreased activation of left posterior inferior frontal cortex, damaged in most patients, and extralesional remote decreases of activity within polar parts of the inferior temporal gyrus (BA38/20) and the occipital cortex (BA19). Taken together, our results demonstrate that jICA may be superior in revealing complex patterns of functional reorganisation in aphasia.
Bibliographic metadata
- Reprints can be obtained from Roland Zahn or Amanda Hicks