Exploring the psychological impact of paediatric head-injury on noninjured siblings; and evaluating the validity of estimates of premorbid executive functioning in older adults
Introduction: The thesis had two objectives. The first was to explore the effects of paediatric traumatic brain injury (TBI) on non-injured siblings. A systematic review investigated psychosocial outcomes for young people with a brother or sister that had sustained a TBI. An empirical study explored the lived experience of being a sibling to a young person who has sustained a moderate or severe TBI. The second objective was to assess the validity of regression equations used to predict older adults expected (or premorbid) test performance on measures of executive functioning. An empirical study conducted external double cross validation of regression equations for three measures of executive function: the Trail Making Test, and the Hayling and Brixton Tests. Methods: Eleven studies were identified via systematic review using predefined criteria. The first empirical study recruited three young people who lived with their siblings who had sustained a moderate to severe TBI within the past five years. Participants engaged in a semi-structured interview and the transcripts were analysed in accordance with interpretative phenomenological analysis. The second empirical study compared observed test performance of 132 older adult participants to an estimate of their performance (as predicted by demographically-based regression equations). New predictive equations were generated. Results: The systematic review indicated that having a sibling who has sustained a TBI is a risk factor for experiencing problems with mood and self-esteem. Overwhelming emotion, ongoing emotional burden, altered family dynamics and resilience and growth were found to be pertinent themes in the empirical study. Caution is necessitated in generalising these results due to the small sample size. In the second study, existing regression equations did not generalise to a new sample and so were not recommended for further use. New predictive models indicate that age and estimated IQ predict performance on tests of executive function; and socioeconomic status and participant sex also influencing performance on the Hayling and Brixton tests respectively. Conclusions: Further high quality research which is adequately powered, has suitable control groups and incorporates child self-report in addition to parent report is needed to address the outcomes and experiences of siblings following paediatric TBI. Regression models for the prediction of test scores need to be validated in a further external sample prior to their application in clinical settings.