Age and gender differences in non-motor symptoms in people with Parkinson's disease.

Background: Non-motor symptoms of Parkinson's disease (PD) are highly prevalent and heterogenic. Previous studies aimed to gain more insight on this heterogeneity by investigating age and gender differences in non-motor symptom severity, but findings were inconsistent. Furthermore, besides examining the single effects of age and gender, the interaction between them in relation to non-motor functioning has -as far as we know- not been investigated before. Objectives: To investigate the association of age and gender identity -as well as the interaction between age and gender identity- with non-motor symptoms and their impact on quality of life. Methods: We combined three large and independent studies. This approach resulted in a total number of unique participants of 1,509. We used linear regression models to assess the association of age and gender identity, and their interaction, with non-motor symptoms and their impact on quality of life. Results: Older people with PD generally had worse cognitive functioning, worse autonomic functioning and worse quality of life. Women with PD generally experienced more anxiety, worse autonomic functioning and worse quality of life compared to men with PD, whereas men with PD generally had worse cognitive functioning. In interaction analyses by age and gender identity, depressive symptoms and anxiety were disproportionally worse with increasing age in women compared to men. Conclusion: Our findings indicate that both age and gender -as well as their interaction- are differentially associated with non-motor symptoms of PD. Both research and clinical practice should pay more attention to demographic subgroups differences and possible different treatment approaches with respect to age and gender. We showed how combining datasets is of added value in this kind of analyses and encourage others to use similar approaches.

Caregiver burden in Parkinson's disease: a mixed-methods study.

BACKGROUND: Providing informal care for a person with Parkinson's disease (PD) can be a demanding process affecting several dimensions of a caregiver's life and potentially causing caregiver burden. Despite the emerging literature on caregiver burden in people with PD, little is known about the inter-relationship between quantitative and qualitative findings. Filling this knowledge gap will provide a more holistic approach to develop and design innovations aiming at reducing or even preventing caregiver burden. This study aimed to characterize the determinants of caregiver burden among informal caregivers of persons with PD, in order to facilitate the development of tailored interventions that reduce caregiver burden. METHODS: We conducted a cross-sectional study in The Netherlands using a sequential mixed methods approach, entailing a quantitative study of 504 persons with PD and their informal caregivers as well as a qualitative study in a representative subsample of 17 informal caregivers. The quantitative study included a standardized questionnaire of caregiver burden (Zarit Burden Inventory) and patient-related (Beck Depression Inventory, State-Trait Anxiety Inventory, Acceptance of Illness Scale, MDS-Unified Parkinson's Disease Rating Scale part II on motor functions in daily life, Self-assessment Parkinson's Disease Disability Score), caregiver-related (Brief Coping Orientation to Problems Experience Inventory, Caregiver Activation Measurement, Multidimensional Scale of Perceived Social Support) and interpersonal determinants (sociodemographic variables including among others gender, age, education, marital status and working status). The qualitative study consisted of semi-structured interviews. Multivariable regression and thematic analysis were used to analyse quantitative and qualitative data, respectively. RESULTS: A total of 337 caregivers were women (66.9%), and the majority of people with PD were men (N = 321, 63.7%). The mean age of persons with PD was 69.9 (standard deviation [SD] 8.1) years, and the mean disease duration was 7.2 (SD 5.2) years. A total of 366 (72.6%) persons with PD had no active employment. The mean age of informal caregivers was 67.5 (SD 9.2) years. Most informal caregivers were female (66.9%), had no active employment (65.9%) and were the spouse of the person with PD (90.7%). The mean Zarit Burden Inventory score was 15.9 (SD 11.7). The quantitative study showed that a lack of active employment of the person affected by PD was associated with a higher caregiver burden. The qualitative study revealed cognitive decline and psychological or emotional deficits of the person with PD as additional patient-related determinants of higher caregiver burden. The following caregiver-related and interpersonal determinants were associated with higher caregiver burden: low social support (quantitative study), concerns about the future (qualitative study), the caregiving-induced requirement of restrictions in everyday life (qualitative study), changes in the relationship with the person with PD (qualitative study) and a problem-focused or avoidant coping style (both studies). Integration of both data strands revealed that qualitative findings expanded quantitative findings by (1) distinguishing between the impact of the relationship with the person with PD and the relationship with others on perceived social support, (2) revealing the impact of non-motor symptoms next to motor symptoms and (3) revealing the following additional factors impacting caregiver burden: concern about the future, perceived restrictions and limitations in performing daily activities due to the disease, and negative feelings and emotional well-being. Qualitative findings were discordant with the quantitative finding demonstrating that problem-focused was associated with a higher caregiver burden. Factor analyses showed three sub-dimensions of the Zarit Burden Inventory: (i) role intensity and resource strain, (2) social restriction and anger and (3) self-criticism. Quantitative analysis showed that avoidant coping was a determinant for all three subscales, whereas problem-solved coping and perceived social support were significant predictors on two subscales, role intensity and resource strain and self-criticism. CONCLUSIONS: The burden experienced by informal caregivers of persons with PD is determined by a complex interplay of patient-related, caregiver-related and interpersonal characteristics. Our study highlights the utility of a mixed-methods approach to unravel the multidimensional burden experienced by informal caregivers of persons with chronic disease. We also offer starting points for the development of a tailored supportive approach for caregivers.