Evaluating the outcome of interventions on quality of life in dementia: selection of the appropriate scale.
BACKGROUND: A literature study was conducted to contribute to an adequate use of quality of life (QoL) instruments for the evaluation of interventions in dementia care by providing an overview of properties of QoL measures that acknowledge domains important to dementia patients. METHODS: Domains important to patients, and domains that professional caregivers in different settings focus on, are compared to domains represented in nine QoL instruments. Data on psychometrics and applicability are generated. RESULTS: Four instruments best represent domains of QoL important to patients and domains professional caregivers in 24-h care and daytime activities focus on. Two are self-rating instruments: Schedule for the Evaluation of Individual Quality of Life, applicable in mild dementia, measuring individual QoL of patient and informal caregiver, and Quality of Life-Alzheimer's Disease Scale, which can be applied up to moderately severe dementia. For patients with advanced dementia receiving residential care, the observational instruments Qualidem and Discomfort scale-Dementia of Alzheimer Type are recommended. The first is easily administered by nurse assistants or occupational therapists and covers several QoL domains on which they focus in daily practice. The second can be used by various professionals. CONCLUSIONS: QoL assessment provides a format for patients and (in)formal caregivers to express whether an intervention has made an important difference to the patient's life. Improvement of QoL in dementia should have high priority in care, treatment and research. This study shows that severity of dementia, care type, setting, and the specific QoL domains an intervention focuses on, determine which QoL instrument is most appropriate in a specific situation.