Response shift in hearing related quality of life after cochlear implantation - effect size and clinical significance: a then-test study

BackgroundQuality of life questionnaires are often used in the assessment of rehabilitation of hearing-impaired patients with a cochlear implant. However, a prospective study with a systematic retrospective evaluation of the preoperative quality of life after surgery has not yet been conducted and may reveal a change in internal standards, such as a response shift, due to the implantation and hearing rehabilitation.MethodsThe Nijmegen Cochlear Implant Questionnaire (NCIQ) was used for assessing hearing related quality of life. It has three general domains (physical, psychological and social) and six subdomains. Seventeen patients were tested before (t(0)) and retrospectively (then-test; pre-t(1)) and acutely postoperative (post-t(1)) after cochlear implantation. Observed changes, then-test changes, response shifts and effect sizes were calculated. Non-parametric statistical methods were used.ResultsThe NCIQ total score was 52.32 +/- 18.69 (mean, standard deviation) for t(0), 59.29 +/- 14.06 for pre-t(1) and 67.65 +/- 26.02 for post-t(1) questioning. The observed change was statistically significant in all domains but in speech production. Response shift was statistically significant in the total score and in part of the domains. The effect sizes for the response shift were moderate (> 0.5) in the total score, psychological, social general scores and subdomains.ConclusionsIn this study we found that response shift does exist in adults with severe to profound hearing loss undergoing cochlear implantation. By advising the participants to deactivate the implant for the then-test, recall bias and noise were minimized. The clinical significance of the response shift was present in the total score and in the social and psychological domains.