CONVERSATIONAL ASSESSMENT FOLLOWING TRAUMATIC BRAIN INJURY - A COMPARISON ACROSS 2 CONTROL-GROUPS

Although changes in discourse are frequently referred to in the trauma tic brain injury (TBI) literature, they are difficult to objectify and measure. It is not always easy, therefore, for clinicians to differen tiate between discourse behaviours which may have been present premorb idly, 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 refer ence to the premorbid sociolinguistic characteristics of the TBI popul ation. A second aim of the study was to examine the relationship betwe en discourse impairment following TBI and severity of injury. Twenty-s ix TBI participants were compared with 26 non-brain-injured orthopaedi c patients, and 26 university students, using Damico's Clinical Discou rse Analysis (CDA). As predicted, global measures derived from the CDA did not differentiate the groups. The TBI group was, however, found t o differ significantly from both control groups on a modified measure (CDA-M) which removes discourse errors that occurred with similar freq uency across the three groups. Performance on this measure correlated significantly with severity of injury. Further, it was found that ther e were quantitative and qualitative differences between two severity s ubgroups in the TBI group with respect to their CDA-M profiles. While nearly all members of the TBI group made errors associated with inform ation transfer, only the more severely injured TBI participants made e rrors in parameters which seem to be associated with more fundamental 'rules' of conversational interaction. The results are discussed in re lation to the psychosocial implications of the findings, together with issues in sampling and measuring conversational discourse in the TBI population.