Cross-cultural adaptation of the German version of the Quality of Life in Alzheimer ’ s Disease scale-Nursing Home version ( QoL-AD NH ) Dementia

Cross-cultural adaptation of the German version of the Quality of Life in Alzheimer’s Disease scale Nursing Home version (QoL-AD NH) Dementia is a chronic and currently incurable syndrome. Therefore, quality of life (QoL) is a major goal when caring for people with dementia (Gibson et al., 2010) and a major outcome in dementia research (Moniz-Cook et al., 2008). The measurement of QoL, especially proxy-rating, is challenging because of the proxy-perspective (Pickard and Knight, 2005), reliability (Dichter et al., 2016), validity (O’Rourke et al., 2015), and responsiveness (Perales et al., 2013). Probably due to these challenges, it has not been possible to show positive effects for QoL in almost all non-pharmacological interventions for people with dementia (Cooper et al., 2012). One recommended (Moniz-Cook et al., 2008) and frequently used instrument is the Quality of Life in Alzheimer’s Disease scale (QoL-AD), which was originally developed in the US for community-dwelling people with dementia. The QoL-AD consists of 13 items based on a 4-point Likert scale ranging from “1”=poor to “4”=excellent (Logsdon et al., 1999). The original instrument has been adapted for people living in nursing homes (NH) by Edelmann et al. (2005). For the NH version, two items of the original version (Money, Marriage) were removed and four items added (People who work here, Ability to take care of oneself, Ability to live with others, and Ability to make choices in one’s life). Both the original version and the NH version allow self-rating of QoL by people with dementia themselves as well as proxy-rating by family members or professional caregivers (Logsdon et al., 1999). Whereas a detailed user manual is available for self-rating, none is available for proxy-rating. Thus, it is unclear whether the items have to be rated from a proxy-proxy or patient-proxy perspective. Based on a proxy-proxy perspective, the caregiver assesses the QoL of a person with dementia from the proxy perspective. This perspective differs more from a QoL self-rating than it does from a patientproxy perspective. In the latter perspective, a proxy assesses the QoL of a person with dementia just as he/she thinks that the person with dementia would rate him or herself (Pickard and Knight, 2005). Ratings of patients’ QoL from a proxy perspective differ more from patients’ self-ratings than ratings of a proxy taken from the patient’s perspective (Pickard and Knight, 2005). Since only the Qol-AD 13-item version was available in German, we carried out a crosscultural adaptation of the QoL-AD NH, applying an established guideline (Beaton et al., 2000) consisting of five steps (translation, synthesis, backtranslation, expert committee review, pretesting). During the forward translation process, two persons independently translated items and response options into German. Both translators were native German speakers with excellent English language skills. Both forward translations were synthesized into one preliminary German version after discussion of ambiguities and discrepancies. Two English native speaker translators performed the back-translation. These translators have excellent skills in German and both have been involved with translation issues in research before. Both were blinded to the original English version of the QoL-AD. The two backward translated versions were compared and discrepancies were highlighted. All four translators, one additional dementia researcher, one NH manager experienced in the field of dementia care, and the project coordinator discussed the results. Agreement was achieved for all items except one. For item 2 (Energy) the expert committee was not confident whether only the single word “Energy” or the alternative term “Motivation” could convey the meaning regarding the physical and psychological components of the item. Therefore, two translations of item 2 (Energy) and one for each of the remaining 14 items were looked at carefully in cognitive interviews with caregivers as proxy-raters (Willis, 2005). The convenience sample consisted of 29 professional caregivers from four NHs who were interviewed individually (n = 14) or in three focus groups (n = 15). NHs collaborating in previous and recent studies were asked for participation (Köpke et al., 2012; Richter et al., 2015). In all NHs both a focus group interview and individual interviews were conducted. Participants were recruited by NH managers and could choose between participation in focus groups or individual interviews. Before the interview participants were not familiar with the QoL-AD NH. At the beginning of the interview, each caregiver rated (patient-proxy) a person with a formal dementia diagnosis whom he/she knew well. Ratings lasted 3.2 minutes on average (see table S1). Afterwards, each caregiver was asked about his understanding of the QoL-AD NH items based on different cognitive probes (Willis, 2005). The study was approved by the ethic committee of the University of Lübeck (14–239).