Automated Creak Differentiates Adductor Laryngeal Dystonia and Muscle Tension Dysphonia.

OBJECTIVE: The purpose of this study was to determine whether automated estimates of vocal creak would differentiate speakers with adductor laryngeal dystonia (AdLD) from speakers with muscle tension dysphonia (MTD) and speakers without voice disorders. METHODS: Sixteen speakers with AdLD, sixteen speakers with MTD, and sixteen speakers without voice disorders were recorded in a quiet environment reading aloud a standard paragraph. An open-source creak detector was used to calculate the percentage of creak (% creak) in each of the speaker's six recorded sentences. RESULTS: A Kruskal-Wallis one-way analysis of variance revealed a statistically significant effect of group on the % creak with a large effect size. Pairwise Wilcoxon tests revealed a statistically significant difference in % creak between speakers with AdLD and controls as well as between speakers with AdLD and MTD. Receiver operating characteristic curve analyses indicated that % creak differentiated AdLD from both controls and speakers with MTD with high sensitivity and specificity (area under the curve statistics of 0.94 and 0.86, respectively). CONCLUSION: Percentage of creak as calculated by an automated creak detector may be useful as a quantitative indicator of AdLD, demonstrating the potential for use as a screening tool or to aid in a differential diagnosis. LEVEL OF EVIDENCE: 3 Laryngoscope, 133:2687-2694, 2023.

Effects of Sidetone Amplification on Vocal Function During Telecommunication.

PURPOSE: Society has become increasingly dependent on telecommunication, which has been shown to negatively impact vocal function. This study explores the use of sidetone regulation during audio-visual communication as one potential technique to alleviate the effects of telecommunication on the voice. METHOD: The speech acoustics of 18 participants with typical voices were measured during conversational tasks during three conditions of sidetone amplification: baseline (no sidetone amplification), low sidetone amplification, and high sidetone amplification. Vocal intensity, vocal quality (estimated using acoustic measures of the low-high ratio and the smoothed cepstral peak prominence), and self-perceived vocal effort were used to measure the impacts of sidetone amplification on vocal function. RESULTS: Compared to baseline, there were statistically significant decreases in vocal intensity and increases in low-high ratio in the high level of sidetone amplification condition. Changes in these measures were not significantly correlated. When asked to rank conditions based on their perceived vocal effort, participants most often ranked the high level of sidetone amplification as least effortful; however, the visual-analog ratings of vocal effort were not significantly different between conditions. The smoothed cepstral peak prominence did not change with varying levels of sidetone amplification. CONCLUSIONS: Vocal intensity decreased with high levels of sidetone amplification. High levels of sidetone amplification also resulted in increases in the low-high ratio, which were shown to be more than just a byproduct of decreased vocal intensity. The impact of sidetone amplification on vocal effort was less clear, but results suggested that participants generally decreased their vocal effort with increased levels of sidetone amplification. This was a preliminary study and future work is warranted in a population of participants with voice complaints and in a more noisy, realistic environments.

Spectral Aggregate of the High-Passed Fundamental Frequency and Its Relationship to the Primary Acoustic Features of Adductor Laryngeal Dystonia.

OBJECTIVE: Currently, no clinically feasible objective measures exist that are specific to the signs of adductor laryngeal dystonia (LD), deterring effective diagnosis and treatment. This project sought to establish concurrent validity of a new automated acoustic outcome measure, designed to be specific to adductor laryngeal dystonia (AdLD): the spectral aggregate of the high-passed fundamental frequency contour (SAHf o). METHOD: Twenty speakers with AdLD read voiced phoneme-loaded (more symptomatic) and voiceless phoneme-loaded (less symptomatic) sentences. LD discontinuities (defined as phonatory breaks, frequency shifts, and creak), the acoustic ramifications of laryngeal spasms, were manually identified. The frequency content of the f o contour was examined as a function of time, and content above 1000 Hz was summed to automatically calculate SAHf o. Multiple linear regression analysis was applied to SAHf o based on LD discontinuities and sentence type (voiced or voiceless phoneme-loaded). RESULTS: The regression model accounted for 41.1% of the variance in SAHf o. Both the LD discontinuities and sentence type were statistically related to SAHf o. CONCLUSION: Results of this study provide evidence of concurrent validity. SAHf o is an automatic outcome measure specific to acoustic signs of AdLD that may be useful to track treatment progress.

Clinical Cutoff Scores for Acoustic Indices of Vocal Hyperfunction That Combine Relative Fundamental Frequency and Cepstral Peak Prominence.

PURPOSE: This study examined the discriminative ability of acoustic indices of vocal hyperfunction combining smoothed cepstral peak prominence (CPPS) and relative fundamental frequency (RFF). METHOD: Demographic, CPPS, and RFF parameters were entered into logistic regression models trained on two 1:1 case-control groups: individuals with and without nonphonotraumatic vocal hyperfunction (NPVH; n = 360) and phonotraumatic vocal hyperfunction (PVH; n = 240). Equations from the final models were used to predict group membership in two independent test sets (n = 100 each). RESULTS: Both CPPS and RFF parameters significantly improved model fits for NPVH and PVH after accounting for demographics. CPPS explained unique variance beyond RFF in both models. RFF explained unique variance beyond CPPS in the PVH model. Final models included CPPS and RFF offset parameters for both NPVH and PVH; RFF onset parameters were significant only in the PVH model. Area under the receiver operating characteristic curve analysis for the independent test sets revealed acceptable classification for NPVH (72%) and good classification for PVH (86%). CONCLUSIONS: A combination of CPPS and RFF parameters showed better discriminative ability than either measure alone for PVH. Clinical cutoff scores for acoustic indices of vocal hyperfunction are proposed for assessment and screening purposes.

The Relationship Between Physiological Mechanisms and the Self-Perception of Vocal Effort.

Purpose This study aimed to examine the relationship between a large set of hypothesized physiological measures of vocal effort and self-ratings of vocal effort. Method Twenty-six healthy adults modulated speech rate and vocal effort during repetitions of the utterance /ifi/, followed by self-perceptual ratings of vocal effort on a visual analog scale. Physiological measures included (a) intrinsic laryngeal tension via kinematic stiffness ratios determined from high-speed laryngoscopy, (b) extrinsic suprahyoid and infrahyoid laryngeal tension via normalized percent activations and durations derived from surface electromyography, (c) supraglottal compression via expert visual-perceptual ratings, and (d) subglottal pressure via magnitude of neck surface vibrations from an accelerometer signal. Results Individual statistical models revealed that all of the physiological predictors, except for kinematic stiffness ratios, were significantly predictive of self-ratings of vocal effort. However, a combined regression model analysis yielded only 3 significant predictors: subglottal pressure, mediolateral supraglottal compression, and the normalized percent activation of the suprahyoid muscles (adjusted R 2 = .60). Conclusions Vocal effort manifests as increases in specific laryngeal physiological measures. Further work is needed to examine these measures in combination with other contributing factors, as well as in speakers with dysphonia.

Estimating Vocal Fold Contact Pressure from Raw Laryngeal High-Speed Videoendoscopy Using a Hertz Contact Model.

The development of trauma-induced lesions of the vocal folds (VFs) has been linked to a high collision pressure on the VF surface. However, there are no direct methods for the clinical assessment of VF collision, thus limiting the objective assessment of these disorders. In this study, we develop a video processing technique to directly quantify the mechanical impact of the VFs using solely laryngeal kinematic data. The technique is based on an edge tracking framework that estimates the kinematic sequence of each VF edge with a Kalman filter approach and a Hertzian impact model to predict the contact force during the collision. The proposed formulation overcomes several limitations of prior efforts since it uses a more relevant VF contact geometry, it does not require calibrated physical dimensions, it is normalized by the tissue properties, and it applies a correction factor for using a superior view only. The proposed approach is validated against numerical models, silicone vocal fold models, and prior studies. A case study with high-speed videoendoscopy recordings provides initial insights between the sound pressure level and contact pressure. Thus, the proposed method has a high potential in clinical practice and could also be adapted to operate with laryngeal stroboscopic systems.