Ultrasonographic Respiratory Muscle Assessment in Parkinson's Disease (NCT07308795)

Ultrasonographic Respiratory Muscle Assessment in Parkinson's Disease (NCT07308795)

Overview

Ultrasonographic Respiratory Muscle Assessment in Parkinson's Disease (NCT07308795)

Overview

This observational case-control study investigates the involvement of respiratory muscles in [Parkinson's disease](/diseases/parkinsons-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["@ultrasonography_pd"][@respiratory_muscle_pd].

Trial Information

| 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 |

Scientific Rationale

Respiratory Dysfunction in Parkinson's Disease

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[@respiratory_muscle_pd].

Why Ultrasound Assessment?

Ultrasound imaging offers several advantages for assessing respiratory muscle involvement in PD:

• Non-invasive: No radiation exposure, suitable for repeated measurements
• Portable: Can be performed at bedside
• Real-time: Visualizes muscle thickness during different respiratory phases
• Quantitative: Provides objective measurements of muscle architecture

Clinical Significance

Respiratory muscle weakness in PD contributes to:

• Reduced cough efficiency: Impaired clearance of secretions, increasing pneumonia risk
• Exercise intolerance: Limited aerobic capacity due to inadequate ventilatory reserve
• Sleep-disordered breathing: Nocturnal hypoventilation and obstructive events
• Dysphagia: Shared neural circuitry for respiratory and swallow coordination

Study Design

Methodology

This is an observational, cross-sectional, case-control study comparing:

• PD Group: Patients with Parkinson's disease (Modified Hoehn and Yahr stages 1-2-3)
• Control Group: Age and gender-matched healthy volunteers

Assessments Performed

| 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 |

Ultrasound Measurement Protocol

Muscle thickness measurements are performed in the supine position with standardized conditions:

• Patient supine with arms resting symmetrically beside the trunk
• Lower extremities in full knee extension with intermalleolar distance of 10 cm
• Measurements recorded at end of normal expiration and end of forced expiration
• Multiple sites assessed for each muscle group

Outcome Measures

Primary Outcomes

| 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. |

Secondary Outcomes

| 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. |

Eligibility Criteria

Inclusion Criteria

• Age > 18 years
• Diagnosis of [Parkinson's disease](/diseases/parkinsons-disease) with Modified Hoehn and Yahr stages 1-2-3
• Mini-Mental State Examination (MMSE) score > 23 (adequate cognitive capacity for testing)
• Body Mass Index (BMI) < 30

Exclusion Criteria

• Active smokers
• Diagnosis of active chest disease (COPD, asthma, interstitial lung disease)
• Hemodynamic instability
• Unstable vital signs
• Parkinson's patients not adequately controlled with medical treatment
• Parkinson Plus syndromes (MSA, PSP, CBS, etc.)
• Neuromuscular diseases affecting respiratory muscles

Clinical Relevance

Correlation with Disease Severity

A key objective of this study is to establish the relationship between respiratory muscle abnormalities and disease stage. Understanding this correlation could:

Implications for Rehabilitation

Findings from this study could inform respiratory rehabilitation programs for [Parkinson's disease](/diseases/parkinsons-disease)[@pd_respiratory_rehabilitation]:

• Inspiratory muscle training: Targeting diaphragmatic and accessory inspiratory muscles
• Expiratory muscle training: Enhancing cough effectiveness and airway clearance
• Postural interventions: Optimizing mechanics of breathing

Disease Staging by Hoehn and Yahr

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 |

Cross-Links to NeuroWiki

• [Parkinson's Disease](/diseases/parkinsons-disease) — Target indication
• [Respiratory Dysfunction in PD](/mechanisms/pd-respiratory-dysfunction) — Related mechanism
• [Non-Motor Symptoms in PD](/mechanisms/pd-non-motor-symptoms) — Related symptoms
• [Substantia Nigra Dopaminergic Neurons](/cell-types/substantia-nigra-compacta-dopamine-neurons) — Affected cell type
• [Autonomic Dysfunction in PD](/mechanisms/pd-autonomic-dysfunction) — Related dysfunction
• [Pulmonary Complications in Neurodegeneration](/mechanisms/pulmonary-complications-neurodegeneration) — Related mechanism

Limitations and Considerations

Study Design Considerations

Clinical Translation

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.

References