Factor structure of patient and caregiver ratings on the dementia quality of life instrument.

Preliminary evidence suggests that quality of life reports from patients diagnosed with mild cognitive impairment (MCI) and mild Alzheimer's disease (AD) are as reliable and valid as data provided by caregivers. To date, no studies compared the factor structure of data provided by caregivers and patients. Factor analyses are important to conduct because they are an indicator of validity. This study compared the factor structure of patient and caregiver reports on the Dementia Quality of Life scale (DQoL). Participants (N=67) were patients diagnosed with amnestic MCI or mild AD and their caregivers. Principal axis factor analyses were run separately on patient and caregiver report data. The three-factor solutions for patient and caregiver data were nearly identical. Three factors corresponding to positive affect, negative affect, and aesthetics emerged reliably from analyses. Thus, data from patients demonstrated a factor structure that was highly consistent with caregiver report data and conformed to meaningful psychological constructs.