This observational case-control study investigates the involvement of respiratory muscles in Parkinson's disease using ultrasonography. The study evaluates whether abdominal accessory respiratory muscle thickness correlates with disease severity and expiratory respiratory muscle strength in Parkinson's disease patients at different Hoehn and Yahr stages.
Respiratory dysfunction is a significant yet under-recognized complication of Parkinson's disease, affecting up to 50% of patients and contributing to increased morbidity and mortality. This study aims to characterize these abnormalities using non-invasive ultrasound imaging, potentially informing rehabilitation strategies for respiratory impairment in PD[1][2].
| Attribute | Details |
|---|---|
| NCT Number | NCT07308795 |
| Title | Ultrasonographic Evaluation of Abdominal Accessory Respiratory Muscle Thickness in Patients With Parkinson's Disease: Correlation With Disease Severity and Expiratory Respiratory Muscle Strength |
| Phase | Observational (Case-Control) |
| Status | Recruiting |
| Sponsor | Istanbul Physical Medicine Rehabilitation Training and Research Hospital |
| Principal Investigator | Ayşe Nur Sarıkoç, Assistant Doctor |
| Participants | 36 (estimated) |
| Start Date | December 29, 2025 |
| Completion Date | April 20, 2026 |
| Study Design | Cross-sectional, case-control |
| Location | Istanbul, Turkey |
Respiratory complications in Parkinson's disease arise from multiple mechanisms:
The diaphragmatic and accessory respiratory muscles may be affected by the same neurodegenerative processes that impact other skeletal muscles in PD[2:1].
Ultrasound imaging offers several advantages for assessing respiratory muscle involvement in PD:
Studies have demonstrated that ultrasound can reliably measure diaphragm thickness and abdominal muscle thickness, correlating with respiratory function in neurological conditions[3].
Respiratory muscle weakness in PD contributes to:
Early identification of respiratory muscle dysfunction could enable targeted rehabilitation interventions[4].
This is an observational, cross-sectional, case-control study comparing:
| Assessment | Purpose |
|---|---|
| Ultrasonography | Measure thickness of rectus abdominis, external oblique, internal oblique, and transversus abdominis muscles |
| Maximal Inspiratory Pressure (MIP) | Assess strength of inspiratory respiratory muscles |
| Maximal Expiratory Pressure (MEP) | Assess strength of expiratory respiratory muscles |
| 6-Minute Walk Test | Evaluate functional exercise capacity |
| Modified Hoehn and Yahr Staging | Quantify disease severity and progression |
Muscle thickness measurements are performed in the supine position with standardized conditions:
| Measure | Description |
|---|---|
| Maximal Expiratory Pressure (MEP) | Maximum pressure generated during forced expiration, reflecting abdominal and accessory expiratory muscle strength. Measured using MicroRPM Respiratory Pressure Meter (MicroDirect, USA). |
| Maximal Inspiratory Pressure (MIP) | Maximum negative pressure generated during maximal inspiratory effort from residual volume, reflecting diaphragmatic and inspiratory muscle strength. |
| Ultrasonographic Muscle Thickness | Thickness measurements of rectus abdominis, external oblique, internal oblique, and transversus abdominis muscles at rest and during forced expiration. |
| Measure | Description |
|---|---|
| 6-Minute Walk Test | Distance walked in 6 minutes, assessing functional exercise capacity and aerobic reserve. |
| Modified Hoehn and Yahr Stage | Clinical staging system (1-5, with intermediate stages 1.5 and 2.5) for Parkinson's disease severity. |
A key objective of this study is to establish the relationship between respiratory muscle abnormalities and disease stage. Understanding this correlation could:
Findings from this study could inform respiratory rehabilitation programs for Parkinson's disease[4:1]:
The Modified Hoehn and Yahr scale stages PD severity:
| Stage | Description |
|---|---|
| 1 | Unilateral involvement only |
| 1.5 | Unilateral and axial involvement |
| 2 | Bilateral involvement without balance impairment |
| 2.5 | Mild bilateral involvement with recovery on pull test |
| 3 | Mild to moderate bilateral involvement; some postural instability |
| 4 | Severe disability; still able to walk or stand unassisted |
| 5 | Wheelchair-bound or bedridden unless aided |
This observational study, while providing valuable mechanistic insights, is not a therapeutic trial. The findings would need to be validated in larger studies and translated into rehabilitation protocols before clinical implementation.
Ultrasound assessment of respiratory muscles in Parkinson's disease. Parkinsonism Relat Disord. 2020. ↩︎
Respiratory dysfunction in Parkinson's disease. J Neurol Sci. 2019. ↩︎ ↩︎
Reliability of ultrasound for measuring muscle thickness. Skeletal Radiol. 2018. ↩︎
Respiratory rehabilitation in Parkinson's disease. Arch Phys Med Rehabil. 2021. ↩︎ ↩︎