Validity, reliability, and feasibility of a quality of life questionnaire for people with dementia.

The present study investigates the validity, reliability, and applicability of the German version of the QUALIDEM, which is used to measure the quality of life of people with dementia in nursing homes. The sample consists of data from 203 people (average age 84 ± 9 years, 74% female) with mild to moderate dementia and 283 persons (average age 86 ± 8 years, 79% female) with severe to very severe dementia. These are baseline data from two lighthouse projects on dementia (STI-D and InDemA). The investigation of the feasibility is based on four expert interviews. The construct validity of the 37-item version of the QUALIDEM shown by the factors satisfied behavior, unapproachable and unsatisfied behavior, positive self-image, negative affect, social relations, feeling at home, restless tense behavior, and having something to do were identified. Furthermore, for the 18-item version the following four factors were computed: satisfied behavior, unapproachable and unsatisfied behavior, restless tense behavior, and negative affect. Cronbach's α values for the determined factors are between 0.64 and 0.87 (37-item version) and between 0.61 and 0.83 (18-item version), which corresponds with a medium to high reliability (internal consistency). Furthermore, the student assistants assessed the QUALIDEM as applicable and practical.