The proximal probe in esophageal pH monitoring: development of a normative database.

Healthy volunteers without symptoms of either gastroesophageal reflux or laryngopharyngeal reflux and without abnormalities on laryngologic examination were recruited for esophageal pH monitoring. Thirty subjects underwent ambulatory 24-hour double-channel pH probe monitoring to establish normative data for the upper probe, which was positioned just above the upper esophageal sphincter. Data were analyzed excluding meal periods plus 2 minutes of postprandial time. The mean, standard deviation, median, and 95th percentile were calculated for various reflux parameters for the following intervals: total study duration, upright time, supine time, and postprandial time. Normal subjects display physiologic reflux above the upper esophageal sphincter (median one event, 95th percentile 6.9 events), and 80.4% of these events occur in the upright position. The reflux area index (RAI) appears to be the most useful parameter to measure laryngopharyngeal reflux severity.

Respiratory and glottal efficiency measures in normal classically trained singers.

Respiratory and glottal efficiency measures were collected from a pool of 40 classically trained singers with normal larynges. All singers had > or = 3 years of formal classical voice training and were active professional solo classical singers. Mean flow rates were obtained from all subjects to assess glottal efficiency. Additionally, maximum phonation times and phonation quotients were obtained from a subset of the singers. Pulmonary function test data on forced expiratory volume, forced vital capacity, and forced expiratory flow were obtained for all subjects. Results were compared with published normal values, not specifically derived from trained singers, used commonly in voice laboratories. Differences were found, suggesting the need for separate normative data to be used for evaluation of the vocal athlete.