The Trunk Control Test: relations with respiratory muscle strength and peak expiratory cough flow

Introduction: Stroke patients commonly have impaired cough function. The role of trunk muscles in cough effectiveness has been poorly addressed. The Trunk Control Test (TCT) is a simple test that assesses trunk stability. This study was aimed to determine whether TCT is related to respiratory muscle strength and peak expiratory cough flow (PECF). Methods: Cross-sectional assessment of 96 stroke patients admitted in a rehabilitation ward. Inclusion criteria: first-ever stroke, and time since stroke onset <3 weeks. Main outcome variables were PECF (assessed with the Mini Wright Peak Flow Meter), respiratory muscle strength (estimated with maximal inspiratory and expiratory pressures [PImax and PEmax, respectively]), and trunk muscle function (assessed with the TCT). Statistical analysis: Lineal and multiple regression analysis. Results: Ninety six stroke patients (62.8 ±11.7, years, 72.9% men, NIHSS: 5.1±3.2, mini-mental: 26.7±2.8) had reduced PECF (254.1 SD 84.1 L/min) and respiratory muscle strength (PImax 55.8±24.6 and PEmax 82.5±34.9 cmH2O, respectively). Lineal regression analysis showed that PECF was statistically associated with PEmax (β 0.92, 95%CI 0.47-1.38, p<0.00) PImax (β 1.22, 95%CI 0.58-1.87, p<0.00) and TCT (β 0.76, 95%CI 0.67-1.47, p<0.03). In a multiple regression analysis, no statistically significant associations were observed. Conclusion: Trunk muscle function is associated with impairments on cough effectiveness which may increase the risk to develop chest infections. Interventions aiming to improve respiratory and trunk muscles function must be considered in stroke patients.