Measurement reliability of phonation threshold pressure in pediatric subjects.

Objectives/Hypothesis Phonation threshold pressure (PTP), the minimum subglottal pressure (P-s) required for phonation, is sensitive to changes in laryngeal biomechanics and is often elevated with pathology. Little is reported on PTP in children; challenges with task performance and measurement reliability represent barriers to routine clinical assessment. Study Design Pilot study evaluating PTP and P-s measurement reliability in children using labial and mechanical interruption. Methods Twenty-two subjects aged 4 to 17 years (10.7 +/- 3.9 years) participated. Ten trials were performed for each method; task order was randomized. For labial interruption, subjects produced /p alpha/ five times at softest (onset PTP) and comfortable amplitude. For mechanical interruption, subjects produced a sustained /alpha/ while a balloon valve interrupted phonation five times for 250 ms each; mechanical interruption was performed with a mouthpiece and mask. PTP was recorded as the difference between P-s and supraglottal pressure at phonation cessation (offset PTP). Mean PTP and P-s and intrasubject coefficients of variation were compared. Correlations with age were evaluated. Results Mean PTP (P < .001) and P-s (P = .005) were higher for labial interruption. Intrasubject coefficients of variation for PTP (P = .554) and P-s (P = .305) were similar across methods. Coefficient of variation was related to age for mechanical-mask trials only (r = -0.628, P = .00175). Conclusions Differences in means are likely related to differences in task and PTP hysteresis effect. Reliability is comparable with all methods; using a mouthpiece may be preferable to a mask for mechanical interruption. Measurement of PTP is noninvasive, reliable, and may be a useful adjunct in pediatric voice assessment. Level of Evidence 3b Laryngoscope, 129:1520-1526, 2019