Retest Reliability for Complete Airway Interruption Systems of Aerodynamic Measurement.

INTRODUCTION: Measures of subglottal pressure (Ps), phonation threshold pressure (PTP), and laryngeal resistance (LR) can be used as indicators of vocal cord disorders. The gold standard non-invasive measurement uses labial interruption, which has been shown to have reliability inconsistencies. Mechanical interruption methods have demonstrated promise in measurement reliability. The goal of the present study is to compare retest reliability of labial and mechanical interruption methods. METHODS: 55 subjects aged 18-69 participated. Ten trials were performed for each method. For labial interruption, subjects produced five labial plosives at comfortable and quiet volumes. For mechanical interruption, subjects produced a sustained /α/ while a balloon valve interrupted phonation five times. Thirty subjects completed a second study visit identical to the first approximately two weeks (15 days ± 3.76) after the first visit. Ps, PTP, mean airflow rate, and LR were determined for each subject and retest reliability for each was analyzed. RESULTS: The percent difference in measurement results for test-retest of Ps were 12.88% ± 10.15 for mechanical interruption and 27.56% ± 17.14 for labial interruption (P = 0.0003). The percent difference for PTP measurements were 21.46% ± 16.01 for mechanical and 17.04% ± 14.62 (P = 0.3372) for labial. Intra-subject coefficients of variation of Ps were 0.086 ± 0.046 for mechanical and 0.161 ± 0.078 for labial (P < 0.0001). For PTP, the coefficients were 0.177 ± 0.083 for mechanical and 0.186 ± 0.091 for labial (P = 0.5402). Lastly, for LR (Ps divided by mean airflow rate) the percent differences were 14.33% ± 10.06 for mechanical and 53.87% ± 43.19 for labial (P < 0.0001) with intra-subject variability of 0.115 ± 0.050 for mechanical and 0.287 ± 0.222 for labial (P < 0.0001). CONCLUSIONS: Ps and LR measured using mechanical interruption showed more consistency for both retesting across separate study visits and intra-subject variability. PTP was similar in retesting and intra-subject variability. Continued work to improve mechanical interruption techniques is warranted as these methods offer higher reliability and consistency than the labial interruption methods.

Joint and segment sequencing and its relationship to ball velocity and throwing arm kinetics in professional pitchers.

BACKGROUND: Temporal variations during the pitch have demonstrated significant impacts on the kinetic chain, and as such, have implications in injury risk. PURPOSE: To determine the effect of varying chronological orders of maximum joint and segment velocities on ball velocity and upper extremity kinetics. METHODS: Professional baseball pitchers (n = 287) were assessed with 3D-motion capture (480 Hz) while pitching. Pitches were categorized into one of the following groups dependent on the first maximum joint or segment velocity achieved out of chronological order in an inferior to superior direction: knee extension (DscK), pelvis rotation (DscP), trunk rotation (DscT), shoulder rotation (DscS), forearm pronation (DscF), and Proper (for pitchers with the correct temporal sequence), and Total Population, for all pitchers. Ten normalized throwing arm kinetic variables were compared among groups. Regression analysis was conducted on the timing of maximum velocities with ball velocity. RESULTS: The majority of pitches were in the DscK group (64.5%). The DscK group had a significantly slower maximum lead knee extension velocity compared with the Proper group (253°/s vs. 316°/s, P = .017). The Proper group had a significantly faster ball velocity compared with the Total Population (39.0 ± 1.9 m/s vs. 38.3 ± 2.1 m/s, P = .013). The DscP group had a significantly slower maximum pelvis rotation velocity compared with the Proper group (596°/s vs. 698°/s, P < .001). The Proper group had no significant difference in kinetics relative to the population. For every 1 standard deviation delay in attaining maximum lead knee extension velocity, ball velocity increased by 0.38 m/s (B = 3.5, ß = 0.18, P < .001). For every 1 standard deviation delay in timing to achieve maximum pelvis rotation velocity, maximum pelvis rotation velocity and ball velocity increased by 22.5°/s (B = 1107.0, ß = 0.23, P < .001) and 0.48 m/s (B = 23.4, ß = 0.23, P < .001), respectively. CONCLUSION: Pitchers with a discordant sequence of knee extension and pelvis rotation velocity timing had significantly slower corresponding segment/joint velocities. Conversely, pitchers with a proper sequence had the fastest ball velocity with minimal differences in throwing arm kinetics. To maximize ball velocity, professional pitchers should consider achieving maximal velocities in an inferior to superior chronological sequence, with a particular focus on the knee and pelvis.

Age and Sex Comparison of Aerodynamic Phonation Measurements Using Noninvasive Assessment.

Purpose The goal of this study was to present vocal aerodynamic measurements from pediatric and adult participant pools. There are a number of anatomical changes involving the larynx and vocal folds that occur as children age and become adults. Data were collected using two methods of noninvasive aerodynamic assessment: mechanical interruption and labial interruption. Method A total of 154 participants aged 4-24 years old took part in this study. Ten trials were performed for both methods of airway interruption. To perform mechanical interruption, participants phonated /α/ for 10 s trials while a balloon valve interrupted phonation 5 times. For labial interruption, participants said /pα/ 5 times at comfortable and quiet volumes. Aerodynamic measures included subglottal pressure, phonation threshold pressure, mean airflow, laryngeal resistance, and others. Results One hundred one participants (51 females) successfully completed testing with both methods. Eight out of 20 measurements were found to have a statistically significant effect of participant age on measurements. Sex alone had a significant effect on vocal efficiency for the labial quiet method. Conclusions The data discussed here can be used to view age and sex trends in vocal aerodynamic measurements. When using either method of mechanical or labial interruption, participant age needs to be taken into account to properly interpret several aerodynamic parameters. A participant's sex is not as important when using these methods.

Measurement Reliability of Laryngeal Resistance and Mean Flow Rate in Pediatric Subjects.

OBJECTIVE: Mean flow rate (MFR) and laryngeal resistance (RL) are sensitive to changes in glottal configuration and biomechanics. There is little reported on aerodynamic parameters in children. We conducted a pilot study to evaluate MFR and RL measurement reliability in a pediatric population using labial and mechanical interruption methods. METHOD: Thirty-nine subjects aged 4-17 performed 10 trials per method. For labial interruptions, subjects produced five labial plosives at a comfortable amplitude. For mechanical interruptions, subjects maintained a steady /α/ while a balloon valve interrupted their airflow five times for 250 milliseconds each. MFR was measured as the flow through the interruption device between interruptions. RL was calculated by dividing subglottal pressure (Ps) by MFR. The primary outcome measures of this study were the coefficients of variation of MFR and RL. Paired t tests were used to compare each variable between the two methods. Pearson's correlation was used to analyze the relationship between each parameter and subject age. RESULTS: Mean PS (t(38) = 2.966, P < 0.01) and RL (t(38)=3.563, P < 0.01) were higher for labial interruptions while mean MFR (t(38) = -2.036, P < 0.05) was lower. Intrasubject coefficients of variation were higher for the labial technique for both MFR (t(38) = 4.939, P < 0.001) and RL (t(38) = 3.439, P < 0.01) while there was no difference in PS variability (P = 0.260). Mean MFR and RL were related to age for both the labial (MFR: r = 0.588, P < 0.001; RL: r = -0.468, p = 0.003) and mechanical trials (MFR: r = 0.534, P < 0.001; RL: r = -0.496, P = 0.001). The coefficients of variation for RL were negatively correlated with age for both labial (r = -0.415, P = 0.009) and mechanical trials (r = -0.471, P = 0.002). MFR was only correlated in the labial trials (r = -0.514, P = 0.001) and PS was only correlated in the mechanical trials (r = -0.519, P = 0.001). CONCLUSIONS: Differences in means and intrasubject variation are likely due to differences in task and measurement timing. Precision of MFR and RL measurement in pediatric subjects was higher for mechanical interruption; further exploration of this method and its clinical utility is warranted. Measurement of aerodynamic parameters may be a useful addition to pediatric voice assessment.

Effects of Angle of Epiglottis on Aerodynamic and Acoustic Parameters in Excised Canine Larynges.

OBJECTIVES: The aim of this study is to explore the effects of the angle of epiglottis (Aepi) on phonation and resonance in excised canine larynges. METHODS: The anatomic Aepi was measured for 14 excised canine larynges as a control. Then, the Aepis were manually adjusted to 60° and 90° in each larynx. Aerodynamic and acoustic parameters, including mean flow rate, sound pressure level, jitter, shimmer, fundamental frequency (F0), and formants (F1'-F4'), were measured with a subglottal pressure of 1.5 kPa. Simple linear regression analysis between acoustic and aerodynamic parameters and the Aepi of the control was performed, and an analysis of variance comparing the acoustic and aerodynamic parameters of the three treatments was carried out. RESULTS: The results of the study are as follows: (1) the larynges with larger anatomic Aepi had significantly lower jitter, shimmer, formant 1, and formant 2; (2) phonation threshold flow was significantly different for the three treatments; and (3) mean flow rate and sound pressure level were significantly different between the 60° and the 90° treatments of the 14 larynges. CONCLUSIONS: The Aepi was proposed for the first time in this study. The Aepi plays an important role in phonation and resonance of excised canine larynges.

Measurement reliability of phonation threshold pressure in pediatric subjects.

OBJECTIVES/HYPOTHESIS: Phonation threshold pressure (PTP), the minimum subglottal pressure (Ps ) 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 Ps 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 /pα/ five times at softest (onset PTP) and comfortable amplitude. For mechanical interruption, subjects produced a sustained /α/ 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 Ps and supraglottal pressure at phonation cessation (offset PTP). Mean PTP and Ps and intrasubject coefficients of variation were compared. Correlations with age were evaluated. RESULTS: Mean PTP (P < .001) and Ps (P = .005) were higher for labial interruption. Intrasubject coefficients of variation for PTP (P = .554) and Ps (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.