Conversational assessment following traumatic brain injury: a comparison across two control groups

Abstract

Although changes in discourse are frequently referred to in the traumatic brain injury TBI literature, they are difficult to objectify and measure. It is not always easy, therefore, for clinicians to differentiate between discourse behaviours which may have been present premorbidly, and those which are uniquely associated with TBI. The major aim of this study was to systematically examine and describe the nature of conversational impairment following severe TBI, with particular reference to the pre morbid sociolinguistic characteristics of the TBI population. A second aim of the study was to examine the relationship between discourse impairment following TBI and severity of injury. Twenty six TBI participants were compared with 26 non brain injured orthopaedic patients, and 26 university stu dents, using Damico s Clinical Discourse Analysis CDA. As predicted, global measures derived from the CDA did not differentiate the groups. The TBI group was, however, found to differ significantly from both control groups on a modified measure CDA M which removes discourse errors that occurred with similar frequency across the three groups. Performance on this measure correlated significantly with severity of injury. Further, it was found that there were quantitative and qualitative differences between two severity subgroups in the TBI group with respect to their CDA M profiles. While nearly all members of the TBI group made errors associated with information transfer, only the more severely injured TBI participants made errors in parameters which seem to be associated with more fundamental rules of conversational interaction. The results are discussed in relation to the psychosocial implications of the findings, together with issues in sampling and measuring conversa tional discourse in the TBI population.