Co-manifestation of swallowing dysfunction indicators and vocal fold motion impairment within a shared neural substrate in patients with brain injury: a cross-sectional study

Background Vocal fold motion impairment (VFMI) is a common but frequently overlooked complication in patients with brain injury and can significantly compromise multiple airway protective functions—including glottic closure during swallowing, cough reflex, and cough effectiveness—leading to increased risks of aspiration, pneumonia, and poor clinical outcomes. Although swallowing dysfunction and VFMI often coexist in patients with brain injury, the specific characteristics and underlying mechanisms of their association have not been systematically investigated. Methods This single-center cross-sectional study consecutively enrolled 280 patients with brain injury from June 2024 to May 2025. All patients underwent fiberoptic endoscopic evaluation of swallowing (FEES) to simultaneously assess 18 swallowing indicators covering 5 dimensions and vocal fold motor function. VFMI was defined as complete fixation or hypomotility of the vocal folds under endoscopy. Multivariable logistic regression analysis identified swallowing indicators that significantly co-occurred with VFMI after adjusting for potential confounders. To address the extreme collinearity between bilateral pyriform sinus secretion variables (Spearman r = 0.974), a composite maximum-score variable [PS_MAX = max(left, right)] was constructed. Results Among 280 patients, 220 (78.6%) had VFMI. After adjusting for confounders, restricted pharyngeal wall movement (OR = 2.16, 95% CI: 1.06–4.38, p = 0.034) and pyriform sinus secretion pooling (PS_MAX: OR = 2.165, 95% CI: 1.067–4.396, p = 0.032) consistently co-manifested with VFMI, suggesting their co-occurrence as expressions of shared pharyngolaryngeal neural substrate impairment. Conclusion Restricted pharyngeal wall movement and pyriform sinus secretion pooling co-manifest with VFMI as integrated expressions of a shared neural injury substrate—specifically, the overlapping brainstem circuits including the nucleus ambiguus and related pathways that co-regulate pharyngeal constrictor function and vocal cord motor control—rather than as independently co-occurring phenomena. VFMI should be regarded as part of the broader swallowing and airway-protective dysfunction spectrum—encompassing both degglutitive impairment and compromised airway-protective functions including cough reflex and cough effectiveness—caused by brainstem network impairment, rather than an isolated laryngeal disorder. These findings have direct clinical implications in settings where vocal fold status is not simultaneously available, supporting more integrated evaluation and rehabilitation planning that addresses swallowing, cough, and airway-protective function.