Exploratory ultrasonographic evaluation of parasternal intercostal muscle asymmetry in hemiparesis following stroke: a case-control ultrasonographic study.

PURPOSE: Diaphragmatic weakness is a known cause of respiratory dysfunction in stroke. However, the role of extra-diaphragmatic muscles in this regard remains unclear. The aim of this study was to evaluate parasternal intercostal muscle thickness and asymmetry between the two sides in hemiparetic patients after stroke using ultrasonography and to provide exploratory and hypothesis-generating data regarding inspiratory muscle involvement and thoracic mechanical changes. METHODS: This prospective case-control study included 30 stroke patients and 30 healthy volunteers. Demographic data, parasternal intercostal muscle thickness measured by ultrasound, and pulmonary function test (PFT) results were recorded for all participants. RESULTS: Muscle thickness at both the end of expiration and the end of inspiration and thickening rates were found to be statistically significantly decreased on the paretic side compared with the non-paretic and dominant sides (p<0.050). No statistically significant difference was detected in terms of non-paretic and dominant muscle thickness and thickening rate (p>0.050). No statistically significant relationship was detected in the correlation analysis between paretic and non-paretic intercostal muscles of stroke patients and PFT parameters (p>0.050). CONCLUSION: Parasternal intercostal muscle thickness measurements show significant asymmetry between the two sides in hemiparetic patients after stroke. However, this asymmetry is not related to PFT and cannot be interpreted as a direct indicator of respiratory dysfunction. The findings may indicate localized inspiratory muscle involvement and thoracic mechanical changes.