The purpose of this study is to evaluate the effectiveness of Transcutaneous Auricular Vagus Nerve Stimulation (TAVSS) in improving respiratory muscle strength and function in chronic stroke patients. It aims to explore TAVSS as a potential complementary approach in enhancing rehabilitation outcomes for this population.
Introduction Stroke is one of the leading causes of morbidity and long-term disability worldwide. Respiratory muscle weakness is a common complication in stroke patients, leading to respiratory dysfunction, increased aspiration risk, and higher mortality. Post-stroke, reduced vital capacity, maximum inspiratory and expiratory pressure, and low expiratory reserve volume significantly affect respiratory muscle function. Objective This study aims to investigate the effects of Transcutaneous Auricular Vagus Nerve Stimulation (TAVSS) on respiratory parameters in chronic stroke patients. Participants and Methods The study included 50 chronic stroke patients in their 1st to 3rd year post-stroke, meeting specific motor levels in Brunnstrom Staging. Participants were randomized equally into experimental (TAVSS + conventional physiotherapy) and control (sham TAVSS + conventional physiotherapy) groups. Treatment Protocol Experimental Group: TAVSS and conventional physiotherapy were applied three times per week for a total of 10 sessions. TAVSS was delivered for 20 minutes using a biphasic asymmetric waveform. Control Group: Sham TAVSS (without current) and conventional physiotherapy were applied with the same frequency and duration. Both groups received individualized physiotherapy protocols, including strengthening, stretching, balance exercises, electrotherapy, and neurodevelopmental treatment. Measurements and Evaluation Chest circumference measurements were taken at the axillary, epigastric, and subcostal regions during deep inspiration and expiration using a tape measure. Respiratory function parameters (Maximum Inspiratory Pressure, Maximum Expiratory Pressure, Forced Expiratory Volume in 1 Second, Forced Vital Capacity, Forced Expiratory Volume in 1 Second to Forced Vital Capacity Ratio) were measured using the Minispir 2 spirometer before treatment and after the 10th session. Conclusion and Recommendations The study aims to evaluate the impact of TAVSS on improving respiratory muscle strength and function, presenting an alternative approach in stroke rehabilitation. TAVSS is expected to support respiratory function and positively influence rehabilitation outcomes in stroke patients
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
TRIPLE
Enrollment
50
TAVSS is an application system that uses an electrical transcutaneous stimulation device placed on the concha or tragus of the ear. Functional Magnetic Resonance Imaging studies have shown that stimulation of these areas activates the ipsilateral nucleus tractus solitarius (NTS) via vagal projections to the brainstem and forebrain. Unlike cervical vagus nerve stimulation, TAVSS utilizes a physiological pathway to activate the NTS and the dorsal motor nucleus, which subsequently sends impulses bilaterally to the heart surface via efferent cervical vagus nerves. Therefore, this technique eliminates the possibility of directly and asymmetrically stimulating cardiac motor efferent fibers, which could lead to adverse cardiac events. TAVSS combines advantageous qualities such as being non-invasive, cost-effective, convenient, and efficient.
Mediworld Medical Center Physical Therapy and Rehabilitation Department
Istanbul, Turkey (Türkiye)
RECRUITINGInspiratory muscle strength
Inspiratory muscle strength will be measured using the Minispir 2 spirometer by Medical International Research. This spirometer, classified as a Class II medical device (medium risk) by Health Canada, is a non-invasive tool for assessing respiratory function. It evaluates lung ventilation by measuring the air volume during inspiration and expiration. The device records inspiratory effort and lung capacity, helping determine respiratory muscle performance.
Time frame: From enrollment to the end of treatment at 4 weeks
Expiratory muscle strength
Expiratory muscle strength will be measured using the Minispir 2 spirometer by Medical International Research. This spirometer, classified as a Class II medical device (medium risk) by Health Canada, is a non-invasive tool for assessing respiratory function. It evaluates lung ventilation by measuring air volume during expiration, helping assess expiratory muscle performance and overall pulmonary function.
Time frame: From enrollment to the end of treatment at 4 weeks
Forced Expiratory Volume in 1 Second (FEV₁)
Forced Expiratory Volume in 1 Second (FEV₁) will be measured using the Minispir 2 spirometer by Medical International Research. This spirometer, classified as a Class II medical device (medium risk) by Health Canada, is a non-invasive tool for assessing respiratory function. It evaluates lung ventilation by measuring the air volume exhaled in the first second of a forced expiration, providing critical data on airway obstruction and pulmonary function.
Time frame: From enrollment to the end of treatment at 4 weeks
Forced Vital Capacity (FVC)
Forced Vital Capacity (FVC) will be measured using the Minispir 2 spirometer by Medical International Research. This spirometer, classified as a Class II medical device (medium risk) by Health Canada, is a non-invasive tool for assessing respiratory function. It evaluates lung ventilation by measuring the maximum air volume forcefully exhaled after a deep inhalation, providing essential data on pulmonary function and lung capacity.
Time frame: From enrollment to the end of treatment at 4 weeks
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Forced Expiratory Volume in 1 Second (FEV₁) to Forced Vital Capacity (FVC)
Forced Expiratory Volume in 1 Second (FEV₁) to Forced Vital Capacity (FVC) ratio will be measured using the Minispir 2 spirometer by Medical International Research. This spirometer, classified as a Class II medical device (medium risk) by Health Canada, is a non-invasive tool for assessing respiratory function. It evaluates lung ventilation by determining the proportion of air exhaled in the first second relative to total forced vital capacity, providing key insights into airway obstruction and pulmonary function.
Time frame: From enrollment to the end of treatment at 4 weeks
Chest Circumference Measurement
The chest circumference of patients in the Experimental and Control groups will be measured during deep inspiration and expiration using a measuring tape. Measurements will be taken at the axillary, epigastric, and subcostal regions as both baseline (initial) and post-treatment (final) assessments.
Time frame: From enrollment to the end of treatment at 4 weeks