This clinical trial investigates the effects of visual feedback from the SpiroGym mobile application on Expiratory Muscle Strength Training (EMST) performance in patients with Parkinson's Disease. The study is conducted at the General University Hospital in Prague, Czechia, and represents an innovative approach to addressing respiratory dysfunction in Parkinson's disease patients through device-assisted breathing exercises.
| Parameter |
Value |
| NCT Number |
NCT06942533 |
| Title |
The Effect of Visual Feedback From the SpiroGym Mobile Application on Expiratory Muscle Strength Training Performance in Patients With Parkinson's Disease |
| Brief Title |
Effect of Visual Feedback From the SpiroGym Mobile Application |
| Status |
Recruiting |
| Phase |
Not Applicable |
| Study Type |
Interventional |
| Enrollment |
30 participants |
| Sponsor |
General University Hospital, Prague |
| Start Date |
May 1, 2025 |
| Completion Date |
July 1, 2026 |
| Locations |
Prague, Czechia |
- Surface Electromyography (sEMG) Measurement — Assessment of abdominal muscle (m. obliquus internus abdominis) activation during expiratory maneuvers
- Peak Cough Flow (PCF) — Evaluation of voluntary cough efficiency
- SpiroGym Sound Intensity (SSI) — Recording the intensity of sound generated by the expiratory device
Respiratory dysfunction is a common and often underappreciated complication of Parkinson's disease, affecting up to 50-90% of patients across various disease stages. This dysfunction manifests through multiple mechanisms:
- Diaphragmatic weakness: The diaphragm, the primary muscle of inspiration, shows reduced contractile force in PD patients
- Abdominal muscle impairment: Expiratory muscles including the internal and external obliques, transversus abdominis, and rectus abdominis demonstrate decreased strength
- Accessory muscle dysfunction: Secondary respiratory muscles show early fatigue and reduced efficiency
Parkinson's disease affects the coordinated muscle activity required for effective cough:
- Reduced cough flow: Peak expiratory flow during cough is significantly diminished
- Impaired glottic closure: Incomplete vocal cord adduction reduces cough effectiveness
- Secretion retention: Inability to clear secretions leads to recurrent respiratory infections
The autonomic nervous system dysfunction in PD extends to respiratory control, affecting the autonomic nervous system:
- Reduced respiratory drive: Central autonomic impairment affects baseline respiratory effort
- Abnormal breathing patterns: Irregular breathing rhythms and reduced variability
- Dysregulated airway tone: Altered autonomic control of bronchial smooth muscle
EMST is a targeted rehabilitation technique designed to improve expiratory muscle function through progressive resistance training. The approach is grounded in the principle of overload and specificity:
- Progressive Resistance: Using devices that provide calibrated resistance to expiratory flow, patients perform repeated maximal expirations
- Muscle Adaptation: Similar to skeletal muscle strength training, expiratory muscles undergo hypertrophy and improved neural recruitment
- Functional Transfer: Improved expiratory strength translates to enhanced cough efficiency and voice production
EMST has demonstrated efficacy in multiple populations:
- Parkinson's disease: Studies show improved cough strength, swallow function, and voice outcomes
- Multiple System Atrophy: Benefits respiratory function and reduces aspiration risk
- Healthy elderly: Improves age-related decline in respiratory muscle function
- Neurological conditions: Effective in stroke, ALS, and traumatic brain injury
The SpiroGym system represents a novel integration of traditional EMST with digital health technology:
- EMST150 Device: A handheld pressure threshold trainer (Aspire Products, LLC, United States) that provides adjustable expiratory resistance
- Mobile Application: Software that uses the phone's microphone to detect expiratory sounds
- Visual Feedback Interface: Real-time display of sound intensity curves, training duration, and progress metrics
During correct performance of the expiratory manoeuvre with the handheld device:
- The exhalation valve opens and the resulting airflow increases the sound level detected by the smartphone microphone
- The application provides real-time visual feedback on the mobile phone screen as a curve depicting the current sound level
- The patient's task is to keep the curve within the training zone, defined by two lines corresponding to the lower and upper thresholds
The key innovation in NCT06942533 is the investigation of visual feedback's impact on training outcomes:
- Real-time Monitoring: Users see their expiratory sound intensity in real-time
- Goal Visualization: Target zones and progress toward goals displayed graphically
- Performance Tracking: Historical data visualization encourages adherence
- Biofeedback Potential: Visual cues may enhance motor learning and muscle recruitment
¶ Alpha-Synuclein and Respiratory Centers
While primarily considered a motor disorder, Parkinson's disease affects multiple brainstem nuclei that control respiration through the accumulation of alpha-synuclein:
- Dorsal respiratory group: Located in the medulla, affected by alpha-synuclein deposition
- Ventral respiratory group: Coordinates accessory muscle activity during forced expiration
- Pneumotaxic center: Located in the pons, regulates breathing rhythm
¶ Lewy Body Pathology in Respiratory Pathways
Research demonstrates that Lewy bodies (aggregated alpha-synuclein) are present in:
- Brainstem respiratory nuclei
- Peripheral autonomic neurons controlling airway smooth muscle
- Enteric nervous system afferents that modulate respiratory reflexes
Respiratory dysfunction in PD contributes to:
- Mortality: Respiratory complications are a leading cause of death in advanced PD
- Quality of Life: Dyspnea, fatigue, and voice changes significantly impact daily functioning
- Aspiration Risk: Weak cough increases pneumonia risk
- Exercise Capacity: Reduced respiratory reserve limits physical therapy effectiveness
The trial employs a prospective crossover design:
- Device: EMST150 pressure threshold trainer (Aspire Products, LLC)
- Application: SpiroGym mobile app for visual feedback (when assigned)
- Protocol: Five sets of five forceful expirations at 75% of maximum expiratory pressure (MEP)
- Duration: Each session conducted at baseline and week 2 (separated by two-week interval)
Each PD patient completes two EMST sessions:
- One session with visual feedback via the SpiroGym app
- One session without the app
The order is randomly assigned. This allows each participant to serve as their own control.
The primary outcome measure uses sEMG to assess muscle activation:
- Target Muscles:
- Internal oblique abdominis (m. obliquus internus abdominis) — primary
- Rectus abdominis (m. rectus abdominis)
- External oblique abdominis (m. obliquus externus abdominis)
- Suprahyoid muscle complex
- Measurement: Wireless electrodes placed on clean skin; Reference Voluntary Contraction (RVC) used for normalization
- Analysis: Comparison of sEMG amplitude between EMST with vs. without SpiroGym conditions
Secondary outcome measures the intensity of sound generated:
- Principle: Louder sound indicates greater expiratory force
- Comparison: SSI values during EMST with vs. without visual feedback
Secondary outcome assessing:
- Perceived exercise difficulty (Likert scale)
- Motivation to perform exercises with vs. without visual feedback
Inclusion:
- Diagnosis of Parkinson's disease
- Stable dopaminergic medication (stable dose for at least 1 month)
Exclusion:
- Other neurological disorders
- Significant cognitive impairment
- Major psychiatric disorder
- History of head or neck cancer or previous surgical interventions in the neck region
- Illness during the study period
Age Range: 40-80 years
This trial aims to establish whether visual feedback enhances EMST effectiveness:
| Hypothesis |
Expected Result |
| sEMG activation |
Greater muscle activation with visual feedback |
| SSI values |
Higher sound intensity (expiratory force) with feedback |
| Perceived difficulty |
Lower difficulty with visual feedback |
| Motivation |
Higher motivation with visual feedback |
The previous pilot study showed that two weeks of intensive EMST with SpiroGym was sufficient to significantly improve voluntary peak cough flow (PCF), with improvement quantitatively comparable to that reported in other intensive EMST studies of longer duration.
This trial represents the intersection of rehabilitation medicine and digital health, testing an innovative approach to addressing respiratory dysfunction in PD:
| Approach |
Stage |
Mechanism |
| EMST + SpiroGym (NCT06942533) |
Recruiting |
Visual feedback-enhanced expiratory training |
| Standard EMST |
Evidence-based |
Progressive resistance breathing exercises |
| Lee Silverman Voice Treatment (LSVT) |
Standard of Care |
Voice and swallow rehabilitation |
Martin Srp, Ph.D.
Chief Physiotherapist
General University Hospital, Prague
Department of Neurology and Centre of Clinical Neuroscience
First Faculty of Medicine, Charles University
Contact: martin.srp@vfn.cz | +420224965513