Individualized vs. global assessments of quality of life after head injury and their susceptibility to response shift

Primary objective: The aim was to compare individualized and global assessments of quality of life (QoL) after traumatic brain injury (TBI) and to investigate perceived changes in QoL. Methods and procedures: The Schedule for the Evaluation of Individual Quality of Life (SEIQoL-DW) and Hadorn's overall 1-10 QoL Scale were administered to 28 participants 1-10 years post-injury together with the GOS-E, HADS and SF-36. Perceived change in quality of life after TBI was investigated by comparing current and retrospective judgements. Main outcome and results: Correlations between the QoL measures confirm validity of the SEIQoL-DW; however, correlations were generally stronger for the simpler 1-10 Scale. Paradoxically, there was little overall change in the mean QoL when current and retrospective judgements were compared; with some participants reporting worse quality of life before injury. A positive change in perceived QoL was associated with better overall functioning. Conclusions: Where an overall rating of QoL is required it seems that Hadorn's 1-10 Scale is a simpler and more direct measure than the SEIQoL-DW. The greater detail provided by the SEIQoL-DW may mean it is of benefit when looking at individual differences. The results suggest that both the SEIQoL-DW and Hadorn's scale are susceptible to response shift (where a person changes the basis on which they evaluate QoL); and this has implications for the interpretation of QoL assessments.