Neurodegenerative diseases (NDDs) raise numerous implications for the health, well-being, and quality of life of both the partner with the disease and their caregiving spouses. In the face of these challenges, numerous studies have sought to understand the experiences of these individuals and evaluate the effectiveness of well-being-centered interventions. While individual approaches are important, the literature has underscored the significance of considering the dyad and the relational processes at play, particularly to optimize such interventions. However, while numerous models detail how couples adjust to chronic illness, NDDs are not integrated into these models, except for a few exceptions, indicating the need for further investigation of couple functioning in the context of NDDs. Therefore, the objectives of this thesis were to better understand the experiences of couples and the dyadic processes underlying their functioning, through a meta-synthesis centered on various NDDs (study 1) and two studies and functioning of couples facing Parkinson’s disease (PD) (studies 2 and 3). Capturing changes in couple functioning across different stages of the disease was another objective.

A thematic synthesis (study 1) and two qualitative empirical studies using Interpretative Phenomenological Analysis (study 2) were conducted. Study 2 explored the experiences of 15 couples at the specific stage known as the honeymoon period of PD. Study 3 involved a comparison of processes identified in three distinct samples of 15 couples, at three stages of PD, to identify prevalent functioning patterns and transitions in couple dynamics throughout the disease progression.

Studies 2 and 3 identified five patterns of dyadic functioning, as well as transitions in dyadic dynamics, often linked to symptom progression. Some partners demonstrate mutual support and positive reinterpretation of their experience, evolving towards a dynamic where the caregiver provides subtle assistance to preserve this balance. For others, this discreet help, a subject of negotiation within the couple from the onset of the disease, abruptly transforms into control. While some spouses struggle against the disease from the early stages by exerting a form of control, their partner disengages. With symptom progression, it becomes impossible to avoid this control, which turns into intrusion. Additionally, some couples adopt a rigid hyperprotection against the distress induced by PD, with this avoidance strengthening over time. Finally, another pattern, characterized by difficulty in understanding the other’s perspective and by a mutual disengagement shown by partners, also becomes more rigid over time, potentially leading to questioning the couple’s relationship.

These studies have highlighted different dyadic dynamics and their associated processes within the context of NDDs, specifically PD. The transitions identified in couple functioning throughout the disease progression indicate the importance of considering the couple’s experience from the onset of the disease and throughout its evolution. These findings are significant, as they suggest several specificities of dyadic functioning in the face of NDDs. Furthermore, they reveal similarities in processes observed in the context of PD, Alzheimer’s disease, or other chronic illnesses. These various aspects are thus important for the development of transdiagnostic interventions and future research aimed at exploring dyadic processes associated with couples’ experience of other less studied diseases.

Keywords: couple, neurodegenerative diseases, marital dynamics, Parkinson's disease, functioning patterns, evolution, caregiving spouses, qualitative methods.