Background and objective: Providing care to people with Parkinson-related dementia (PwPRD) may result in significant stress, strain, and burden for life partners. A common measurement of life partner burden is the Zarit Burden Interview (ZBI), which considers "burden" as a unitary concept; however, burden is highly complex and most likely comprises several dimensions. This study aimed to explore the factor structure of the ZBI in life partners of PwPRD and to examine the relationships among the emerging factors and the demographic and clinical features.
Methods: Life partners of PwPRD participated in home-based quantitative assessments and self-completed postal questionnaires. The assessment battery included ZBI, measures of relationship satisfaction, mood, stress, resilience, health, quality of life, feelings related to care provision, and sociodemographic questions. Data on PwPRDs' motor and neuropsychiatric symptom severity were also elicited in home-based assessments.
Results: An exploratory factor analysis (principal axis factoring) of ZBI, conducted with 127 life partners, revealed five burden dimensions: social and psychological constraints, personal strain, interference with personal life, concerns about future, and guilt. These burden factors were associated with lower relationship satisfaction, mental health, and resilience, and higher stress, anxiety, depression, resentment, negative strain, and PwPRD motor severity. In multiple linear regression analyses, where each factor score was the dependent variable, stress, negative strain, and resentment emerged as significant predictors of specific burden dimensions.
Conclusions: Burden is a complex and multidimensional construct. Interventions should address specific types of burden among life partners of PwPRD to support couples' relationships and maintain quality of life.
Keywords: Lewy body dementia; Parkinson disease dementia; Zarit Burden Interview; caregiver burden; factor analysis.