Effectiveness of cognitive rehabilitation and predictors of quality of life in Parkinson’s disease and psychoeducation in family caregivers

Resumen

Parkinson's disease (PD) is the second most common neurodegenerative disease after Alzheimer's disease. PD is characterized by the presence of motor and non-motor symptoms that affect the quality of life of people with PD. Neuropsychiatric symptoms and cognitive impairment are among the most common non-motor symptoms in PD. Non-pharmacological interventions, specifically, cognitive rehabilitation are developed to improve cognition, clinical, and functional impairment of people with PD. As the disease progresses, the need for caregivers becomes essential, resulting in numerous health and psychosocial problems for the careers themselves. However, there is limited research on interventions of family caregivers. Family caregivers¿ participation in psychoeducation programs may increase the benefits of cognitive rehabilitation in PD and could improve the quality of life of family caregivers. In addition, an increasing number of studies investigate the impact of motor and non-motor symptoms on the Health-related quality of life (HRQoL) of people with PD. However, studies have not taken into account the possible overlap of HRQoL measures with clinical symptom measures. This thesis is composed of three studies. The first study analyzed the efficacy of cognitive rehabilitation in PD through a systematic review and meta-analysis. The second study aimed to evaluate the efficacy of a combined intervention of cognitive rehabilitation in PD patients and psychoeducation in their family caregivers. The third study analyzed predictors of HRQoL in PD before and after removing the overlap of items between HRQoL and clinical measures. The systematic review in study I revealed that attention, working memory, verbal memory, executive functions, and processing speed were the domains that most frequently showed improvements after cognitive rehabilitation. The results of the meta-analysis indicated that global cognitive status and working memory showed moderate effect size; verbal memory, overall cognitive functions, attention, executive functions, visual memory, verbal fluency, processing speed, and depression showed small effects; and visuospatial and visuoconstructive abilities and quality of life showed no effect. In study II, PD patients of the combined group (cognitive rehabilitation in PD patients + psychoeducation in family caregivers) showed improvements in verbal memory, facial emotion recognition, general health, emotional well-being dimension and communication dimension of HRQoL after cognitive rehabilitation; and family caregivers who participated in psychoeducation showed improvements in general health and anxiety scores. In study III, anxiety, fatigue, motor symptoms, and depression were the main predictors of the HRQoL total index in PD patients. However, after controlling overlapping items between HRQoL and clinical measures, fatigue predominated over anxiety, motor symptoms, and depression. In fact, depression was no longer a predictor and neurocognition emerged as a predictor. Regarding dimensions, fatigue predicted mobility, activities of daily living (ADL), emotional well-being, and bodily discomfort dimensions; motor symptoms predicted mobility, ADL, social support, and communication dimensions; anxiety predicted social support, cognition, and bodily discomfort dimensions; and neurocognition predicted communication dimension. In conclusion, findings suggest that cognitive rehabilitation may be beneficial in improving the cognitive functions of people with PD. Moreover, the combined application of cognitive rehabilitation in PD and psychoeducation in family caregivers can provide a comprehensive approach to PD patients and their families, promoting the benefits of cognitive rehabilitation in PD and providing family caregivers with the necessary techniques to improve their health. Finally, fatigue, anxiety, motor symptoms, and neurocognition, but not depression, were identified as the main predictors of HRQoL in patients with PD. These results shed light on the importance of taking into account the overlap of items between HRQoL and clinical measures for an accurate interpretation of the results.