Phonation Threshold Pressure/Flow for Reflecting Glottal Closure in Unilateral Vocal Fold Paralysis.

OBJECTIVE: Previous theoretical analysis predicted that phonation threshold flow (PTF) could be a more sensitive aerodynamic measure than phonation threshold pressure (PTP) for reflecting glottal incompetence. This study investigated the feasibility of whether PTP and PTF may differentiate subjects with unilateral adductor vocal fold paralysis and paresis (UAVFP) from those without, and whether PTP and PTF could reflect the extent of incomplete glottal closure associated with UAVFP. METHODS: PTP and PTF were quantified for 13 subjects with UAVFP and 21 control subjects with normal voice, and the normalized glottal gap area (NGGA) based on videostroboscopic image analysis was quantified for subjects with UAVFP. RESULTS: Significant differences in both PTP and PTF were found between subjects with UAVFP and control subjects. Receiver operating characteristic analysis indicated a higher discriminatory ability of PTP for differentiating subjects with UAVFP from those without (area under the curve of 0.905 for PTP, 0.678 for PTF), yet a significant positive correlation was found between PTF and NGGA (Spearman's ρ = 0.571) but not between PTP and NGGA (ρ = -0.364). CONCLUSION: Results supported the feasibility of using PTP and PTF as potential diagnostic indicators for reflecting glottal closure in UAVFP, with PTP potentially more sensitive for differentiating subjects with and without incomplete glottal closure. These preliminary findings were limited by the small sample size, with further studies needed to verify whether PTF could be more sensitive for reflecting the extent of incomplete glottal closure, as predicted theoretically. LEVEL OF EVIDENCE: 3 Laryngoscope, 131:E1598-E1604, 2021.

Acoustic and Aerodynamic Comparisons of Voice Qualities Produced After Voice Training.

Characteristics of true vocal fold vibration such as the proportion of closed phase of vibration to open phase, longitudinal tension, and the amount of medial compression are used to define four conditions during Estill Voice Training. However, it is unknown whether trainees achieve these phonatory differences after training. Acoustic and aerodynamic measures were used to determine differences in Slack, Thick, Thin, and Stiff conditions. Twenty-four female speech-language pathology graduate students received training perceiving and producing these four conditions and volunteered to participate 3-5 months later. After a 20-minute refresher training, participants were recorded using the Phonatory Aerodynamic System with electroglottography and Computerized Speech Lab. Four Estill Voice Training experts independently categorized the voice quality productions. Aerodynamic and acoustic measures of productions classified by at least three of four experts as having the intended quality determined if measures differentiated among voice qualities and supported the hypothesized physiological concepts used in training at Bonferroni corrected P ≤ 0.0063. Results showed that Slack had low fundamental frequency (fo), low sound pressure level (SPL), and high vibratory instability; Thick had high subglottal pressure (Psg), high SPL, and high vibratory stability; Stiff had high airflow while Thin had lower Psg than Thick. Seven measures differentiated the four qualities with 88.1% accuracy while only Psg, airflow, and jitter were required to differentiate Thick, Stiff, and Thin with 88.7% accuracy. As acoustic and aerodynamic measures differentiated among voice qualities and supported the theoretical physiological characteristics used in training, they could be used to track accuracy during training.

Effectiveness of a Short Voice Training Program for Teachers: A Preliminary Study.

BACKGROUND: Using their voices in inappropriate working conditions causes teachers to misuse their voices, because in order to be heard they need to force their voices. OBJECTIVE: This preliminary study examines the effects of a short-term voice training program aimed at teachers. METHODS: The pre- and posttraining evaluations consisted of acoustic, perceptual (GRBAS [grade, roughness, breathiness, asthenia, and strain]), aerodynamic, and subjective measurements (VHI-10). RESULTS: The results indicate that the voice performance of teachers improves after 25 hours of training. Specifically, significant changes are observed at the acoustic level, in fundamental frequency (F0) and in frequency perturbation measures (Jitter, PPQ [pitch perturbation quotient]), as well as in subjective voice assessment using the Voice Handicap Index (VHI-10), in both the physical subscale (VHI-P) and the total score (VHI-T). CONCLUSIONS: This study confirms the effectiveness of the training program and discusses the most sensitive measures for evaluating the short-term effect of the change.

Test-retest reliability for aerodynamic measures of voice.

OBJECTIVES/HYPOTHESIS: The purpose of this study was to investigate the intrasubject reliability of aerodynamic characteristics of the voice within typical/normal speakers across testing sessions using the Phonatory Aerodynamic System (PAS 6600; KayPENTAX, Montvale, NJ). METHODS: Participants were 60 healthy young adults (30 males and 30 females) between the ages 18 and 31 years with perceptually typical voice. Participants were tested using the PAS 6600 (Phonatory Aerodynamic System) on two separate days with approximately 1 week between each session at approximately the same time of day. Four PAS protocols were conducted (vital capacity, maximum sustained phonation, comfortable sustained phonation, and voicing efficiency) and measures of expiratory volume, maximum phonation time, mean expiratory airflow (during vowel production) and target airflow (obtained via syllable repetition), peak air pressure, aerodynamic power, aerodynamic resistance, and aerodynamic efficiency were obtained during each testing session. Associated acoustic measures of vocal intensity and frequency were also collected. All phonations were elicited at comfortable pitch and loudness. RESULTS: All aerodynamic and associated variables evaluated in this study showed useable test-retest reliability (ie, intraclass correlation coefficients [ICCs] ≥ 0.60). A high degree of mean test-retest reliability was found across all subjects for aerodynamic and associated acoustic measurements of vital capacity, maximum sustained phonation, glottal resistance, and vocal intensity (all with ICCs > 0.75). Although strong ICCs were observed for measures of glottal power and mean expiratory airflow in males, weaker overall results for these measures (ICC range: 0.60-0.67) were observed in females subjects and sizable coefficients of variation were observed for measures of power, resistance, and efficiency in both men and women. Differences in degree of reliability from measure to measure were revealed in greater detail using methods such as ICCs and coefficients of variation than with means comparison testing. The results of this study also show that reliable aerodynamic and associated measures may be elicited using comfortable pitch and loudness. CONCLUSIONS: The 1-week test-retest reliability for the majority of aerodynamic and associated acoustic measures assessed in this study is considered good-to-excellent. Clinicians and researchers using aerodynamic and associated measures should be aware of possible significant gender effects that influence both normative expectations as well as the standard error of measurement (ie, typical error) and estimates of minimum difference that may be used to differentiate typical from disordered voice.