Abstract
Respiratory dysfunction is a clinically important feature of Parkinson’s disease, affecting breathing, physical function, and daily activities. Inspiratory muscle weakness is commonly observed in this population and may contribute to respiratory symptoms such as dyspnoea, which are often under-recognised and under-treated in clinical practice compared with motor symptoms. Despite its impact on daily function and quality of life, interventions to improve respiratory function in Parkinson’s disease have received little attention, highlighting a clear gap in research and a need to explore whether targeted inspiratory muscle training could address this.In other clinical populations, inspiratory muscle training has been shown to increase inspiratory muscle strength, reduce breathlessness, improve exercise capacity, and enhance quality of life. Resistance training of the inspiratory muscles is safe and effective in young healthy adults, athletes, and people with chronic respiratory and cardiovascular diseases. Within these groups, inspiratory muscle training can delay the onset of respiratory muscle fatigue, improve endurance, and enhance symptom control and capacity to perform activities of daily living. These findings provide a strong rationale for investigating whether the benefits of inspiratory muscle training can extend to people with Parkinson's disease, especially given the burden of dyspnoea and the association between respiratory complications and mortality in this population.
Despite the evidence for inspiratory muscle training in other cohorts, there is a lack of robust research for inspiratory muscle training in Parkinson’s disease. This thesis investigates the effects of home-based inspiratory muscle training in people with Parkinson’s disease who experience dyspnoea and are more likely to experience inspiratory muscle weakness, features that position this subgroup as having the potential to benefit from training. It comprises a series of studies that collectively provide novel quantitative and qualitative insights into the potential benefits of inspiratory muscle training in people with Parkinson’s disease.
There are very limited data about the lived experience of the burden of respiratory symptoms in Parkinson’s disease. However, relevant insights can be gained through a comprehensive review of the known impact of respiratory symptoms on quality of life in other chronic conditions. Study 1, a systematic review and meta-aggregation of qualitative studies, establishes that respiratory symptoms in chronic disease are not solely a physical burden but carry significant emotional, psychological, and social consequences. The meta-aggregative approach used provides a rich and nuanced understanding of how symptoms such as dyspnoea, cough and wheezing affect everyday life, reduce physical activity, and diminish quality of life in a wide range of chronic diseases. The synthesis of 50 studies resulted in three key overarching findings related to (1) the emotional burden of respiratory symptoms; (2) the functional and physical limitations of daily life; and (3) how breathlessness impacts the meaning and quality people place on life. Study 1 highlights the multidimensional impact of respiratory symptoms, emphasising the need for a holistic approach to support individuals experiencing respiratory symptoms and to prioritise patient-centred outcomes in interventions aimed at improving respiratory function, as examined in Study 3.
Study 2 presents the protocol for a mixed methods randomised controlled trial investigating the effects of home-based inspiratory muscle training in people with Parkinson’s disease (the outcomes are described in Studies 3 and 4). The randomised trial (Study 3) aims to quantitatively evaluate the impact of inspiratory muscle training on inspiratory muscle strength, exercise capacity, motor aspects of daily living, and quality of life. Study 3, the randomised controlled trial, examined the effects of 8 weeks of home-based high-intensity inspiratory muscle training compared to usual care. With recruitment delayed during the candidature due to external factors, an interim analysis is presented, and recruitment for this study continues as postdoctoral work. At this interim analysis point, participants in the intervention group demonstrated significantly greater improvements in inspiratory muscle strength than those in the control group. While there were trends towards improvement in exercise capacity and cardiovascular responses to exercise, no meaningful changes were observed in dyspnoea, activities of daily living, or quality of life; however, the sample size is underpowered for these outcomes, and this interpretation needs to be tempered accordingly. Although the prevalence of inspiratory muscle weakness in this cohort was relatively low, 8 weeks of inspiratory muscle training still led to measurable gains in inspiratory muscle strength. in these people with Parkinson’s disease.
Finally, Study 4 explores the lived experiences of people with Parkinson’s disease who completed 8 weeks of home-based inspiratory muscle training. Semi-structured interviews were conducted to examine how participants perceived the feasibility, challenges, and benefits of the training. Study 4 revealed that inspiratory muscle training is feasible and acceptable, particularly when regular support from a clinician is available. New insights regarding perceived benefits included improved sleep and feeling less fatigued while speaking. According to these participants, sustaining inspiratory muscle training beyond a structured programme depends on how well training fits into everyday life. These findings highlight the need for flexible, person-centred approaches tailored to the individual and practical realities of living with Parkinson’s disease.
This thesis provides evidence that home-based high-intensity inspiratory muscle training is a feasible and effective intervention for improving inspiratory muscle strength in people with Parkinson’s disease. These novel findings highlight the potential for inspiratory muscle training to serve as an adjunct in rehabilitation to maintain respiratory function in people with Parkinson’s disease. Furthermore, the qualitative data provide important context for interpreting outcomes and insights into how delivery models can be tailored to individual needs, reinforcing the importance of person-centred and sustainable approaches in clinical practice. This thesis extends current knowledge in Parkinson’s disease rehabilitation and informs the design of future interventions targeting respiratory function, an often-overlooked aspect of care in this population.
| Date of Award | 2025 |
|---|---|
| Original language | English |
| Supervisor | Bernie BISSETT (Supervisor), Elisabeth PRESTON (Supervisor) & Allyson FLYNN (Supervisor) |