The aim of this study is to evaluate the morphological and functional characteristics of parasternal intercostal muscles in patients with stroke using ultrasonography. Parasternal intercostal muscle thickness and thickening fraction will be assessed on both the hemiplegic and non-hemiplegic sides. The relationship between ultrasonographic findings and respiratory muscle strength, motor function, balance, functional independence, and quality of life will also be investigated. A healthy control group will be included to establish reference values and enable comparative analyses.
Stroke frequently leads to respiratory muscle dysfunction due to impaired central motor control. Although diaphragm involvement after stroke has been extensively investigated, there is limited evidence regarding the morphological and functional characteristics of extra-diaphragmatic inspiratory muscles, particularly the parasternal intercostal muscles. The primary objective of this study is to evaluate parasternal intercostal muscle morphology and contractility in individuals with stroke using ultrasonography. Parasternal intercostal muscle thickness will be measured at end-tidal expiration and maximal inspiration, and intercostal muscle thickening fraction (ICTf) will be calculated as an indicator of muscle contractility. Measurements will be obtained bilaterally, allowing comparison between the hemiplegic and non-hemiplegic sides. In addition, diaphragm thickness and diaphragm thickening fraction will be assessed using ultrasonography. Respiratory muscle strength will be evaluated by maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) measurements according to ATS/ERS recommendations. Pulmonary function tests including forced vital capacity (FVC), forced expiratory volume in one second (FEV1), and FEV1/FVC ratio will also be performed. Clinical outcomes including motor impairment, balance, functional independence, and stroke-specific quality of life will be assessed using the Fugl-Meyer Assessment, Berg Balance Scale, Functional Independence Measure (FIM), and Stroke-Specific Quality of Life Scale (SS-QoL), respectively. A healthy control group matched for age, sex, and body mass index will be included to establish reference values for parasternal intercostal muscle ultrasonographic measurements and to allow comparative analyses between stroke patients and healthy individuals. The study is designed as a single-center, controlled cross-sectional observational study. A minimum of 40 individuals with stroke and 25 healthy volunteers will be enrolled. Associations between ultrasonographic respiratory muscle measurements and clinical parameters will be analyzed to improve understanding of respiratory muscle involvement after stroke and its relationship with functional outcomes.
Study Type
OBSERVATIONAL
Enrollment
65
Marmara Üniversitesi Tıp Fakültesi
Istanbul, Maltepe, Turkey (Türkiye)
Parasternal Intercostal Muscle Thickening Fraction (ICTf)
Ultrasonographic assessment of parasternal intercostal muscle contractility. Thickening fraction will be calculated as: (Inspiratory Thickness - Expiratory Thickness) / Expiratory Thickness × 100. Higher values indicate greater inspiratory muscle contractile activity. Comparison will be performed between the hemiplegic and non-hemiplegic sides.
Time frame: Baseline
Parasternal Intercostal Muscle Thickness
Ultrasonography will be used to examine the structure and function of the muscle and to measure muscle thickness at the end of inspiration and expiration.
Time frame: Baseline
Intercostal Muscle Asymmetry Index
Intercostal Muscle Asymmetry Index (AI) is a normalized measure of side-to-side differences in parasternal intercostal muscle contractility. The asymmetry index is calculated using the formula \|TF₁ - TF₂\| / \[(TF₁ + TF₂)/2\] × 100, where TF represents the intercostal muscle thickening fraction measured by ultrasonography. Higher values indicate greater asymmetry between the two sides, whereas lower values indicate more symmetrical intercostal muscle function.
Time frame: Baseline
Relative Hemiplegic Deficit
Relative Hemiplegic Deficit is a measure of the reduction in parasternal intercostal muscle contractility on the hemiplegic side relative to the non-hemiplegic side in individuals with stroke. It is calculated using the formula \[(TFnon-hemiplegic - TFhemiplegic) / TFnon-hemiplegic\] × 100, where TF represents the intercostal muscle thickening fraction measured by ultrasonography. Higher values indicate a greater functional deficit of the hemiplegic side, while lower values indicate more preserved intercostal muscle function.
Time frame: Baseline
Diaphragm Thickening Fraction
Diaphragm contractility assessed by ultrasonography. Thickening fraction is calculated as \[(Thickness at maximal inspiration - Thickness at end-expiration) / Thickness at end-expiration\] × 100. Higher values indicate greater diaphragm contractile function.
Time frame: Baseline
Maximal Inspiratory Pressure (MIP)
Maximum inspiratory pressure (MIP) is a measurement that evaluates the strength of the inspiratory muscles. This test measures the negative pressure created when a person breathes in at maximum effort. MIP assesses the strength of respiratory muscles, such as the diaphragm and intercostal muscles, and is used to diagnose conditions characterized by respiratory muscle weakness.
Time frame: Baseline
Maximal Expiratory Pressure (MEP)
Maximum expiratory pressure (MEP) is a measurement that evaluates the strength of the expiratory muscles. This test measures the positive pressure generated when a person exhales with maximum effort. MEP assesses the strength of expiratory muscles, including the abdominal and internal intercostal muscles, and is commonly used to evaluate respiratory muscle function and identify conditions associated with expiratory muscle weakness. Higher values indicate greater expiratory muscle strength.
Time frame: Baseline
Fugl-Meyer Assessment Score
The Fugl-Meyer Assessment (FMA) is a stroke-specific impairment scale used to evaluate motor recovery after stroke. The motor domain score ranges from 0 to 100 points, with higher scores indicating better motor function and less motor impairment.
Time frame: Baseline
Berg Balance Scale Score
The Berg Balance Scale (BBS) consists of 14 tasks assessing static and dynamic balance. Scores range from 0 to 56 points. Higher scores indicate better balance performance and lower fall risk, whereas lower scores indicate greater balance impairment.
Time frame: Baseline
Functional Independence Measure (FIM) Score
The Functional Independence Measure assesses the level of disability and functional independence in activities of daily living. Total scores range from 18 to 126 points. Higher scores indicate greater independence and lower levels of assistance required.
Time frame: Baseline
Stroke-Specific Quality of Life (SS-QoL) Score
Stroke-Specific Quality of Life Scale (SS-QoL) is used to assess the life expectancy of a stroke survivor. It is specifically designed for individuals who have had a stroke. Both personal and psychosocial effects are assessed collectively. Scores range from 49-245. Higher scores indicate better functioning.
Time frame: Baseline
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