The Feasibility of Gastroesophageal Manometry for Continuously Evaluating the Degree of Expiratory Effort During Successful Crescendo Phonation

This study aimed to assess the feasibility of gastroesophageal manometry for continuously evaluating the degree of expiratory effort by measuring the pressures in the digestive tract during crescendo phonation. Each of 18 healthy nondysphonic speakers had a probe with a four-channel gastroesophageal manometer inserted through the nasal cavity to place four pressure sensors in the hypopharynx, cervical-/thoracic esophagus, and stomach, and was asked to gradually increase the vocal loudness during sustained phonation of the vowel /e:/ (vowel-crescendo task), while the sound pressure level and the pressures were simultaneously recorded. 50% of the successful vowel-crescendo task samples with a gradual and adequate sound pressure level increase showed a concomitant gradual increase in both the intra-thoracic-esophageal/intra-gastric pressure values from approximately -5 mmHg /6 mmHg to -10 mmHg/20 mmHg, respectively. The maximum pressure value was the highest in the intra-gastric pressure followed by the intra-thoracic-esophageal and intra-cervical-esophageal pressures in order. However, most of the samples showed less than one of atypical pressure changes, such as fluctuations in the intra-thoracic-esophageal and intra-gastric pressure changes and dispersion in the intra-cervical-esophageal and intra-hypopharyngeal pressure values (perhaps due to the peristaltic motions, and the contact of the sensors to the membranous wall). These results show that, during successful crescendo phonation, gastroesophageal manometry reveals a gradual increase in the intra-thoracic and intra-abdominal pressures with increasing the vocal intensity, even though showing some systematic errors, suggesting the usefulness of gastroesophageal manometry for continuously evaluating the degree of expiratory effort without influence by the laryngeal condition.