Voluntary peak cough flow: A simple and effective tool to predict dysphagia across diverse etiologies

Swallowing and coughing share neural and muscular substrates and play crucial roles in airway protection. This study aimed to compare voluntary peak cough flow (PCF) between patients with various dysphagia etiologies and healthy controls, and to identify a PCF cutoff value for predicting dysphagia. A total of 90 participants were included in the present case-control study. The study group (SG) consisted of 45 patients with FEES-confirmed dysphagia (M/F: 25/20) with a mean ± SD age of 66.64 ± 12.97, and the control group (CG) consisted of 45 age- and gender-matched healthy volunteers (M/F: 25/20) with a mean ± SD age of 65.56 ± 16.39. All participants underwent voluntary PCF measurement using an analog peak flow meter. The cough trials were performed five times for each subject, and the highest value obtained across the trials was recorded as PCF. The SG exhibited significantly lower PCF compared with the CG (206.11 ± 74.22 vs. 287.78 ± 89.31 L/min, p < 0.001). Receiver operating characteristic (ROC) analysis identified a PCF cutoff value of ≤ 252.5 L/min for distinguishing dysphagia, with an area under the curve (AUC) of 0.765 (95% CI: 0.666–0.865), sensitivity of 71.1%, and specificity of 71.1%. Voluntary PCF was significantly reduced in individuals with diverse dysphagia etiologies compared to healthy controls and showed moderate discriminant ability to predict dysphagia. Given its simplicity, low cost, and portability, PCF measurement may serve as a practical adjunctive tool in predicting dysphagia, particularly where instrumental swallowing evaluations are not feasible.