Effect of bolus taste on the esophageal transit of patients with stroke

Stroke is a frequent cause of oropharyngeal dysphagia but may also cause alterations in esophageal motility. The aim of this investigation was to evaluate the effect of bolus taste on the esophageal transit of patients with stroke and controls. Esophageal transit and clearance were evaluated by scintigraphy in 36 patients in the chronic phase of stroke (44-82 years, mean: 63 years) and in 30 controls (33-85 years, mean: 59 years). The patients had a stroke 1-84 months (median: 5.5 months) before the evaluation of esophageal transit. Eight had dysphagia. Each subject swallowed in random order and in the sitting position 5 mL of liquid boluses with bitter (pH=6.0), sour (pH=3.0), sweet (pH=6.9), and neutral (pH=6.8) taste. Transit and clearance duration and the amount of residues were measured in the proximal, middle, and distal esophageal body. There was no difference between patients and controls in esophageal transit or clearance duration. In the distal esophagus, the transit and clearance durations were longer with the sour bolus than with the other boluses in both patients and controls. The amount of residues in the esophageal body was greater in patients than in controls after swallows of the neutral bolus. In control subjects, after swallows of a sour bolus, there was an increase in the amount of residues in the middle and distal esophagus compared with the other boluses. In conclusion, a sour bolus with low pH causes a longer transit and clearance duration in the distal esophageal body. There was no effect of bolus taste or pH on the esophageal transit of patients in the chronic phase of stroke compared with normal volunteers. The longer transit and clearance duration in the distal esophageal body with the sour bolus appears to be a consequence of the low pH of the bolus.