Non-pharmacologic interventions to treat apathy in Parkinson’s disease: A realist review

INTRODUCTION: There is a diverse body of evidence investigating non-pharmacological treatment options for apathy in Parkinson’s disease (PD). We aimed to better understand the context and mechanisms by which non-pharmacological interventions may improve apathy in persons with PD. METHODS: We conducted a realist review of the body of evidence investigating treatment options for apathy in PD. Study authors used findings from a preceding scoping review to identify initial program theory. We then update the scoping review, which was originally conducted in 2017. Two authors independently reviewed and extracted data from studies that discussed non-pharmacological treatment options for apathy in PD. Any data concerning context, mechanisms, and outcomes of interventions for apathy in PD were extracted, synthesized, and analyzed. RESULTS: Our review included nine studies. We categorized studies into two categories, exercise and mindfulness. There were seven exercise interventions included. Exercise interventions evaluated group exercise compared to individual exercise, aerobic exercise, dance, Nordic walking, and an equine program. There were two mindfulness interventions. CONCLUSION: Exercise interventions work best for persons with PD and apathy who are not significantly physically or cognitively impaired, and who have access to transportation, adapted programs, and specialized coaches. Exercise may improve apathy through goal-directed behaviour change and engagement in social interactions. Mindfulness interventions work best for persons with PD and apathy who are not significantly cognitively impaired, have caregiver support, and may improve apathy by targeting the emotional, cognitive, and goal-directed domains that define apathy.