Several studies have suggested that swallowing dysfunction and pulmonary aspiration occur in patients receiving prolonged ventilation. However, the incidence of swallowing dysfunction, its rate of resolution, and the sensitivity of tests used to characterize swallowing abnormalities are not well defined. The goals of our study were to evaluate swallowing function in this group of patients by (1) defining the specific swallowing abnormalities that occur in this patient population, (2) comparing the sensitivity of bedside evaluations to modified barium swallow with videofluoroscopy (MBS/VF), (3) performing endoscopic evaluation of the upper airway to characterize glottic function during swallowing, (4) evaluating the relationship between swallowing dysfunction and neuromuscular disorders, and (5) studying the temporal resolution of swallowing abnormalities. Swallowing function was evaluated in 35 patients receiving prolonged ventilation (ie, > or = 3 weeks) admitted to a specialized rehabilitation unit dedicated to the care of patients requiring prolonged ventilation. The average age of the 35 patients was 61 +/- 15 years. The total duration of intubation at the time of the initial swallowing evaluation was 29 +/- 34 days via a cuffed tracheostomy tube and 15 +/- 9 days via an endotracheal tube. Neuromuscular disorders were present in 16 patients (45%). Thirty-four percent of the patients had at least one swallowing abnormality detected by bedside examination. Results of bedside swallowing examination were abnormal in 31% of patients with a neuromuscular disorder and 37% of patients without a neuromuscular disorder. MBS/VF was abnormal in 83% of patients (85% in patients with and 80% in patients without a neuromuscular disorder). Results of early (< 1 month) repeated MBS/VF examinations usually remained unchanged; however, in a small group of patients, later studies (> or = 1 month) revealed significant improvement. In 50% of patients who underwent direct laryngoscopy, important abnormalities were found that contributed to swallowing dysfunction. Our data show that patients requiring prolonged mechanical ventilation have a high incidence of swallowing abnormalities, regardless of the presence or absence of neuromuscular disorders. MBS/VF and direct laryngoscopy can provide useful information about laryngeal action and swallowing dysfunction, and can facilitate the implementation of corrective actions to prevent respiratory complications.