Plasticity in Human Brain Language Areas After Stroke: What Can the Right Hemisphere Do?

Among the most devastating effects stroke can have on the lives of survivors and those around them are language production and comprehension impairments. The most notable of them - often given the joint diagnostic label of "aphasia" despite their heterogeneity and dissociability - are associated with damage to the brain's left hemisphere, which, in large part for this reason, is considered the "language-dominant" hemisphere. However, the right hemisphere's contribution to language should not be underestimated and may in fact be key to understanding the possibilities and limitations of neuroplasticity for supporting language recovery after stroke. Thus, in this review, we focus on the role of the right hemisphere in supporting human language function, in the neurologically healthy brain and after stroke. We discuss the remarkable capability of the right hemisphere to support normal language abilities after a large left-hemisphere stroke early in life, the more limited capacity for right-hemisphere language support after left-hemisphere stroke in adulthood, and potential interactions between typically left-hemisphere dominant "core" language functions with language functions typically thought to be right-hemisphere dominant, such as emotional prosody. We conclude by highlighting gaps in current knowledge and suggesting areas for future research.