Associations of Peak Cough Flow With Cough Acoustic Features and Respiratory Muscle Surface Electromyography in Poststroke Patients: A Cross-Sectional Observational Study

Purpose: Poststroke ineffective cough impairs airway clearance, increasing respiratory complications. While peak cough flow (PCF) is commonly used to measure cough strength, patient limitations often hinder testing. This cross-sectional study explored the relationships between PCF, cough acoustic features, and respiratory muscle surface electromyography (sEMG) in 28 stroke patients, assessing acoustic metrics to identify diminished cough strength. Method: Participants performed maximal voluntary coughs during simultaneous acoustic and sEMG recordings. Acoustic variables included maximum relative acoustic intensity, rise time, cough duration, relative mean intensity, relative peak energy, spectral centroid (Fc), and spectral bandwidth. Analyses used Spearman correlations with false discovery rate (FDR) correction, linear regression, and receiver operating characteristic (ROC) curves. Results: Among the acoustic variables, only Fc was significantly associated with PCF ( r = −.371, p < .001), and this association remained significant after FDR correction (false discovery rate–adjusted p value = .006). ROC analysis showed that Fc had modest discriminative ability for identifying reduced cough strength (PCF < 270 L/min; area under the curve = 0.671, 95% confidence interval [0.556, 0.786], p = .010). Linear regression further showed that Fc was significantly associated with PCF (β = −.357, p < .001). Conclusions: Fc captures an acoustic characteristic closely associated with poststroke cough airflow. Cough acoustic analysis offers valuable, complementary clinical information when conventional flow testing is challenging. Larger studies are needed to confirm the diagnostic utility of these measures.