a Cognitive impairment in Parkinson's disease and its effect on patients and their carers

Abstract

The progression of Parkinson’s disease (PD), including cognitive decline, is linked to quality of life (QoL), which may subsequently impact on the QoL of their informal carer. This thesis aimed to investigate how cognitive changes affected the QoL of newly diagnosed PDs over 36 months, and the QoL of their carers, using a mixed methods approach. Methods Newly diagnosed PD participants (n=219) completed a schedule of neuropsychological assessments, medical history and QoL measures; these were repeated after 18 months (n=195) and 36 months (n=158). Carers (n=66) completed questionnaires evaluating mood and QoL at 36 months. Purposeful sampling identified participants and their carers with normal cognition, mild cognitive impairment (PD-MCI) and dementia (PDD), who completed qualitative interviews. Results Using the Movement Disorder Society criteria, PD-MCI was a small but significant contributor to QoL in newly diagnosed PD. Over 36 months, most participants were cognitively stable and cognition did not impact on QoL; for the minority who developed PDD and their carers, cognition had a greater impact on QoL. Brief tests, such as MoCA score, modestly predicted declining QoL; attentional deficits had a stronger predictive power. The qualitative analysis revealed three principal themes: the experience of living with PD and cognitive impairment, changes in identity, and coping mechanisms and adjustment. Across these inter-linked themes, the effects of cognitive impairment and the differences between PD and carer experiences were important overarching issues. Conclusions This mixed methods study showed that the determinants of QoL were complex, as was its relationship with cognition. Cognitive impairment, particularly attentional impairment, played a significant role in predicting QoL of PDs and carers. However, ii there was significant individual variation with some people adjusting better than others over time. The qualitative analysis revealed awareness of cognitive decline, changes in roles and anticipatory grief disrupted emotional equilibrium. However protective factors, including optimism, mutually supportive relationships and finding meaning mitigated these factors.