The Effects of Inspiratory Pressures on Diaphragmatic Contraction in People After Stroke

Hong Kong Metropolitan University36 enrolled

Overview

This is a cross-sectional study to determine the optimal inspiratory muscle training (IMT) intensity for stroke survivors. Participants will breathe through a pressure threshold inspiratory loading device with varying loads in random order. Each IMT intensity protocol consists of 10 breaths. During the test, accessory inspiratory muscle activity will be measured with surface electromyography (sEMG) and diaphragm thickness will be used to assessed with ultrasonography. Repeated-measures ANOVA will be used for statistical analysis to determine the most effective training intensity for future study.

Study Type

OBSERVATIONAL

Enrollment

Conditions

Stroke

Interventions

Various intensities of inspiratory muscle trainingDIAGNOSTIC_TEST

Each participant will be asked to perform the lung function test to measure the maximal inspiratory pressure (MIP) after including the study. After the baseline measurement, all participants will be requested to use a nose clip to hold the nose and breathe with the mouth through a pressure threshold inspiratory loading device (POWERbreathe, KH2, England). The inspiratory pressure will be set at 30%, 40%, 50%, 60%, 70%, or 80% of their MIP, in random order. Each MIP intensity protocol consists of 10 breaths. Resting will be allowed between different protocols of contraction intensity (% MIP). During the test, sternocleidomastoid muscle activity will be measured with surface electromyography (sEMG) and diaphragm thickness will be used to assessed with ultrasonography.

Eligibility

Sex: ALLMin age: 18 YearsMax age: 80 YearsHealthy volunteers:

Medical Language ↔ Plain English

Recruitment of participants after a stroke: The inclusion criteria are: * clinical diagnosis of ischemic and/or hemorrhagic stroke. * age ≥ 18 years. * duration of stroke ranges from 1 month to 12 months after diagnosis. * had no facial palsy, which could prevent proper labial occlusion. * had not undergone thoracic or abdominal surgery. * could understand and follow the verbal instruction. * stable cardiac conditions. * no previous history of respiratory problems. The exclusion criteria are: * acute myocardial infarction or acute heart failure. * acute pain on chest or abdominal. * with the clinical signs of significant pulmonary disease. * consciousness impaired. * patient with nasal feeding tube, tracheal tube and/or any condition, which prevent the measurement or training. Recruitment of healthy participants: The inclusion criteria are: * age ≥ 18 years. * had not undergone thoracic or abdominal surgery. * no previous history of respiratory problems. The exclusion criteria are: * acute myocardial infarction or acute heart failure. * acute pain in the chest or abdominal. * with the clinical signs of significant pulmonary disease. * unstable hypertension, arrhythmias, or unstable cardiovascular conditions, such as fluctuations in blood pressure and heart rate, indicate poor cardiac prognosis or the need for vasopressor medications. * pregnant.

Outcomes

Primary Outcomes

Diaphragmatic thickening fraction

Diaphragmatic thickening fraction is determined by "(thickness of the diaphragm at end inspiratory - thickness at end expiratory)/thickness at end expiratory". Diaphragmatic thickness will be measured by ultrasonography.

Time frame: Data will be measured at baseline and at the end of each inspiratory muscle training intensity protocol;

Secondary Outcomes

Muscle activation of the sternocleidomastoid muscle

Surface electromyography will be used to measure accessory inspiratory muscle (sternocleidomastoid muscles) activity during each inspiratory muscle training intensity protocol.

Time frame: Data will be measured at baseline and at the end of each inspiratory muscle training intensity protocol;

Perceived Exertion Borg scale

This is a vertical scale quantified from 0 to 10, where 0 represents no symptoms, and 10 represents the maximum symptoms. The Borg score provides an individual measurement of the exercise intensity.

Time frame: Data will be measured at the end of each inspiratory muscle training intensity protocol;