Recovery and treatment of aphasia after stroke: functional imaging studies

In this review of papers published between May 2006 and May 2007, we discuss functional neuroimaging studies of recovery and treatment of patients with aphasia after stroke.Studies of recovery of aphasia have highlighted the importance of right inferior frontal gyrus activation, especially early after stroke, when it correlates with language recovery. In contrast, in the later stages after stroke left hemisphere activations predict chronic aphasia; speech production recovery appears to depend on left frontal activation, whereas speech comprehension depends on left temporal activation. There have been few studies of treatment of aphasia, but preliminary evidence suggests that treatment of speech production difficulties, even years after stroke, may be effective and deserves further study.Recent studies of aphasia recovery allow a deeper appreciation of the changing neuronal activation patterns associated with time after stroke. The distinction between neuronal reorganization that does and does not sustain recovery in the chronic phase after stroke, either spontaneous or in response to treatment, remains controversial and further studies are necessary. Clinical diagnosis and treatment of aphasia requires many more longitudinal studies with larger patient numbers and more detailed behavioural and lesion characterization of stroke patients.