Fractionation of the components of role play in a right-hemispheric lesioned signer

Role play, a narrative device relying critically on the linguistic reference system of American Sign Language (ASL), also appropriates extrasyntactic devices such as signing style idiosyncrasies and facial caricature for the linguistic purpose of differentiating roles. Whereas the spatialized grammatical reference system has been shown to make demands on left hemisphere processing, role play may require right hemisphere processing. To investigate this issue we analysed role play in a 38-year-old, ASL-fluent, female hearing signer (A. S.) with a right parietal-occipital lesion. A.S, correctly reassigned first person reference, signalling attempted use of role play at the sentence level, despite its spatialized realization in ASL. However, she had difficulty with pragmatically appropriate changes in gaze direction, and with the use of caricature and shifts in body position, to distinguish roles. Analysis of the deficits in this right-lesioned signer's use of a single Linguistic construction that crucially requires both sentence-level and discourse-level devices helps us to refine our concept of the roles of the two cerebral hemispheres in language functions.