title: Variability of Oral and Pharyngeal Transit Between Two Consecutive Swallows in Chagas' Disease.
abstract: BACKGROUND
  Chagas' disease causes dysphagia, regurgitation and retention of food in the esophageal body. Patients have longer pharyngeal clearance, which might be consequent of the involvement of the central nervous system or an adaptation to the esophageal transit impairment. If there is central nervous system involvement by the disease, we expect a larger difference in the oral and pharyngeal phases of swallowing between two consecutive swallows than that seen in controls. Our objective was to evaluate the difference of oral and pharyngeal transit duration between two consecutive swallows in patients with Chagas' disease compared with controls.
  
  
  METHODS
  By videofluoroscopy, the duration of oral and pharyngeal transit, pharyngeal clearance, upper esophageal sphincter transit, hyoid movement and oropharyngeal transit was measured in 17 patients with Chagas' disease and 15 asymptomatic volunteers. Each subject swallowed in duplicate and in sequence 5 mL and 10 mL of barium liquid and 5 mL and 10 mL of barium paste boluses. The differences were calculated between the two swallows of each volume and consistency in patients and controls.
  
  
  RESULTS
  There were no differences between controls and patients in the values of the differences between the two consecutive swallows, except for the hyoid movement duration of the 5 mL liquid bolus, causing a higher difference in controls than in patients.
  
  
  CONCLUSIONS
  Oral and pharyngeal transit variation between two consecutive swallows is similar between patients with Chagas' disease and controls, which suggests that the longer pharyngeal clearance duration previously described is not a consequence of impairment of the central nervous system control of swallowing.
authors: Department of Medicine of the Medical School of Ribeirao Preto, University of Sao Paulo, Ribeirao Preto SP, Brazil.
authors: Roberto Oliveira
authors: RO
authors: Dantas
authors: Department of Medicine of the Medical School of Ribeirao Preto, University of Sao Paulo, Ribeirao Preto SP, Brazil.
authors: Carla Manfredi
authors: CM
authors: Dos Santos
authors: Department of Medicine of the Medical School of Ribeirao Preto, University of Sao Paulo, Ribeirao Preto SP, Brazil.
authors: Rachel
authors: R
authors: de Aguiar Cassiani
authors: Department of Medicine of the Medical School of Ribeirao Preto, University of Sao Paulo, Ribeirao Preto SP, Brazil.
authors: Weslania Viviane
authors: WV
authors: do Nascimento
keywords: Chagas’ disease; Deglutition; Megaesophagus; Pharynx; Swallowing; Swallowing control