Subjective Evaluation of Quality of Life After Brain Injury: Measuring quality of life and the impact of response shift

Abstract

Introduction: After a brain injury there are often long term consequences impacting on QoL. However, this is a complex issue influenced by many factors. As someone recovers and adjusts it is likely that the way in which they evaluate QoL will also change. The theory of response shift suggests people will change the way they evaluate QoL in the face of changes in their life. The aim of this thesis is to investigate what influences a QoL judgement; examining the possibility of response shift. Methods: Quantitative and qualitative methods were used in 4 studies. These were a cross-sectional design utilising an individualised QoL measure (SEIQoL-DW); a longitudinal study utilising a ‘then-test’ approach; a cross-sectional questionnaire study; and a qualitative study using Interpretative Phenomenological Analysis. Study 1 (Ch.3) Results: Correlations between the QoL measures confirm the validity of the SEIQoL-DW; however, correlations were generally stronger for the simpler Hadorn Scale. There was little overall change in mean QoL when current and retrospective judgements were compared. There was evidence for a change in what areas of life were considered most important to QoL following injury. Study 2 (Ch.4) Results: Improvements in reported QoL between baseline and follow-up were small. A then-test indicates that any effect of response shift is small, and non-significant in the current research. There was also little evidence for reprioritisation or re-conceptualisation. Examination of other factors associated with QoL suggest that brain-injury specific factors (BIGI, RBANS) play a role in predicting QoL. Study 3 (Ch.5) Results: QoL was reported as worse post-injury on both Hadorn’s scale and the QOLIBRI-OS; a difference that was more pronounced on the QOLIBRI-OS. Differences were also reported in the importance of different areas of functioning. Change in QoL as measured by the QOLIBRI-OS was significantly influenced by disability as measured by the GOSE, emotional and informational support, and upwards social comparison. Optimism as measured by the LOT, but not upwards social comparison was a significant predictor of change on Hadorn’s scale; GOSE and emotional and informational support remain significant predictors. The GOSE, emotional and informational support, emotional coping styles and optimism were significant predictors of current QoL on the QOLIBRI-OS; and emotional and informational support and optimism were significant predictors of QoL on Hadorn’s scale. Little evidence was found to suggest that the factors proposed in Sprangers and Schwartz’s (1999) model of response shift have predicted relationships with QoL. Two candidate variables were studied: optimism and social support. However neither showed the predicted pattern of relationships. Nonetheless the study supports previous work indicating an influence of optimism and social support on QoL, and indicates that these warrant further study. There were systematic difference between current and retrospective ratings of importance of domains. The level of importance given to the areas of life defined by the QOLIBRI-OS is higher after injury than before, with the exception of “personal and social life” for which there is no significant difference. The areas of life chosen to reflect that which is measured by the GOSE (“work”, “close relationships”, and “social and leisure activities”) are rated as less important with the exception of “close relationships”. These findings provide further support for the idea that QoL domains are re-evaluated after brain injury.

Study 4: This was an in depth qualitative investigation of the experience of recovery and adjustment following TBI. Semi-structured interviews and Interpretative Phenomenological Analysis (IPA) were used. Interviews were conducted with 4 men who were 3, 7, 12, and 18 years post injury. Main Outcome and Results: Themes emerging from the analysis were ‘Change: In Self and World’; ‘Reaching a point of realisation’; ‘Support’; ‘Adjusting to change/Coping with day to day life’; and ‘Participation, Goals and Focus’. These themes cover how participants felt both they and their lives had changed as a consequence of their injury; ways they went about coping and adjusting to changes; the importance of support; and the significance of social integration and participation in feeling satisfied with life. Summary and Conclusions: These studies provide evidence for response shift in different ways. There is little evidence for recalibration but there is some indication that reprioritization or reconceptualization may take place. Changes in how important different areas of life are before and after injury suggest that participants are changing the way they view and make evaluations of QoL. Factors identified as being important to QoL judgements were disability, social support (emotional and informational support identified in the questionnaire study and support in the IPA), upwards social comparison, and optimism. The IPA study suggests that functional outcome and participation are important after TBI; while also identifying ways of coping and providing an insight into the experience of recovery from brain injury. The different QoL measures used provides both evidence for their validity, but also evidence for the different conceptualisations of QoL that are measured by different instruments. The findings have implications both for understanding the QoL of the individual and for research on QoL after TBI.