Talking topically, as it is understood intuitively and evoked metadiscursively, requires constructing an intersubjective orientation to talk that must be continually renewed. Analysis of interactants' ability to orient to topic emergence provides evidence of what is achieved in interaction, as well as why conversational coordination can lapse (Gumperz 1982), resulting in disorientation. Examination of topic emergence is particularly effective for characterizing the disoriented discourse that often follows from acquired brain injury (Coelho, Ylvisaker, and Turkstra 2005), as such discourse-pragmatic impairments are not easily delineated by standard speech-language pathology testing (e.g., of articulation, syntactic complexity, naming); further, the most suitable way to evaluate discourse-pragmatic impairments is through analysis of naturally occurring, dyadic everyday conversation (Cummings 2009). However, the practice of eliciting this everyday conversation presents an inherent contradiction: the intrinsic constraints, goals, and participant roles of clinical discourse elicitation activities used to produce samples of elicitees' talk are in conflict with the less constrained, more symmetrical features of the everyday conversation activity type sought (Hamilton 1994). In this dissertation, I first conceptualize the intuitive notion of topic through analysis of a corpus of naturally occurring conversations among peers, incorporating attention to intersubjective concepts, jointly appreciated salient reasons for talk and interaction, and control of the emergence of talk. I then employ this topic framework to examine three types of clinical elicitation of everyday conversation (participant-managed collection, unstructured interviewing, and clinical protocol), represented in three corpora comprised of speakers with different neurological disorders that commonly result in discourse-pragmatic impairments (stroke, Alzheimer's disease, and traumatic brain injury). The analyses demonstrate that the contrasting patterns of topic emergence in the three clinical discourse elicitation activity types reconstruct and highlight the institutional roles, constraints, and goals in each, particularly regarding pragmatic intersubjectivity of knowledge; understanding of the underlying expectations of the interaction, or frame (e.g., Goffman 1974; Tannen 1993); and levels of control that interactants claimed and surrendered throughout. Thus, the resulting discourse samples manifest more features of asymmetrical institutional interaction than of everyday conversation. This finding has implications for the practice of clinical discourse elicitation and the subsequent evaluation and textualization of discourse-pragmatic impairment. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]