Moderate-severe traumatic brain injury disrupts core mechanisms of online language processing and use.

Successful communication requires identifying and integrating relevant information from the context. When referring to entities in conversation, speakers must distinguish the intended referent from candidate referents in the relevant context, and addressees must interpret the unfolding linguistic expression with respect to the alternatives in that context. While the pressures of speaking and listening differ, both critically involve the online integration of contextual information to support the routine processes of language use. Notably, the contextually appropriate use of language is a common clinical complaint in the population of individuals with traumatic brain injury (TBI), a condition that affects nearly 2 million individuals in the United States annually. Here we test the hypothesis that moderate-severe TBI impacts the language processing mechanisms that support contextually situated language production and comprehension. Forty participants with moderate-severe TBI and forty non-injured comparison participants completed a communication game with a partner as their gaze was monitored. Analyses of the time-course of language use reveal deficits in the online production and comprehension of language, as well as deficits in memory for language. These findings demonstrate that moderate-severe TBI causes deficits not only in domain-general cognitive capacities but also in core language processing mechanisms.