Consensus for voice quality assessment in clinical practice: guidelines of the European Laryngological Society and Union of the European Phoniatricians

Effectiveness of Voice Therapy on Voice Quality and Function in Individuals with Unilateral Vocal Fold Paralysis: Systematic Review and Meta-Analysis

BACKGROUND

Unilateral vocal fold paralysis (UVFP), characterized by immobility of one vocal fold, results from injuries of recurrent laryngeal nerves. Voice therapy is a conservative intervention aiming to address these symptoms, but standard protocols are lacking. In this study, we provided an updated review of voice therapy for UVFP over the past 3 years and analyzed the effect of voice therapy from the perspective of voice assessment recommended by the guidelines of the European Laryngological Society and the Union of the European Phoniatricians in 2023.

METHODS

Following preferred reporting items for systematic reviews and meta-analyses (PRISMA) 2020 statement, we searched the databases, including PubMed, Embase, Web of Science, the Cochrane Library, and SCOPUS, from their earliest records to December 1, 2023. Quality assessment utilized Cochrane Risk of Bias and Risk Of Bias In Non-randomized Studies of Interventions tools. Data extraction encompassed study design, participant characteristics, therapy protocols, and outcome measures, including subjective and objective assessments. We performed heterogeneity analysis by calculating the I2 statistic and meta-analysis by calculating the standardized difference of means and weighted mean differences.

RESULTS

Our systematic review and meta-analysis included 12 studies encompassing 459 patients. The review revealed a predominance of female participants across studies. Therapy protocols primarily included breathing control, laryngeal manipulation, and resonance training, often supplemented by home exercises. Outcome measures demonstrated significant improvements in subjective parameter: Voice Handicap Index ((standard mean difference) SMD = -1.51, P < 0.001), acoustic parameters: fundamental frequency (SMD = -0.38, P = 0.003), jitter (SMD = -0.97, P < 0.001), shimmer (SMD = -0.94, P < 0.001), and noise-to-harmonic ratio (SMD = -0.89, P < 0.001), and aerodynamic parameters: maximum phonation time (SMD = 1.29, P < 0.001), with early intervention yielding enhanced rate of complete glottal closure.

DISCUSSION

Two randomized controlled trials (RCTs) involved patients aware of their allocation to the treatment group, and the remaining 10 studies were retrospective, leading to bias from deviations in the intended intervention. Subjective and aerodynamic parameter inconsistency was observed, but after excluding studies with the onset of UVFP greater than 12 months, the heterogeneity of VHI scores decreased. The funnel plot was grossly symmetrical in the publication bias test. Significant improvements were noted in subjective, acoustic, and aerodynamic outcomes after intervention. Besides, there were commonalities in protocols, such as breathing control, laryngeal manipulation, and resonance training, often supplemented by home exercises.

SYSTEMATIC REVIEW REGISTRATION

This protocol was registered with the International Prospective Register of Systematic Reviews (PROSPERO) on March 28, 2024, registration number: CRD42024529750.

Glottic insufficiency caused by vocal fold atrophy with or without sulcus: systematic review of outcome measurements

PURPOSE

Identifying outcome measurements instruments (OMIs) to evaluate treatment efficacy in patients with vocal fold atrophy and/or sulcus.

METHODS

Systematic review of records published before March 2021 by searching Pubmed and EMBASE. Included studies reported on adults (> 18 year) with dysphonia caused by glottic insufficiency due to vocal fold atrophy with or without sulcus, who were enrolled into a randomized controlled trial, a non-randomized controlled trial, a case-controlled study or a cohort study. All included studies described an intervention with at least one outcome measurement.

RESULTS

A total of 5456 studies were identified. After removing duplicates, screening title and abstract and full text screening of selected records, 34 publications were included in final analysis. From these 50 separate OMIs were recorded and categorized according to the ELS protocol by DeJonckere et al. (Eur Arch Otorhinolaryngol 258: 77-82, 2001). With most OMIs being used in multiple studies the total number of OMIs reported was 265. Nineteen (19) individual OMIs accounted for 80% of reports. The most frequently used OMIs according to category were: VHI and VHI-10 (subjective evaluation); G of GRBAS (perceptual evaluation); F0, Jitter and Shimmer (acoustic evaluation); MPT and MFR (aerodynamic evaluation) and glottic closure and mucosal wave (endoscopic evaluation). Of these OMIs VHI had a high percentage of significance of 90%.

CONCLUSION

This systematic review identifies the most used OMIs in patients with glottic incompetency due to vocal fold atrophy and/or sulcus as a step toward defining a Core Outcome Set (COS) for this population.

PROSPERO REGISTRATION

238274.

Comparison of TEVA vs. PRAAT in the Acoustic Characterization of the Tracheoesophageal Voice in Laryngectomized Patients

Background: Previous studies have assessed the capability of PRAAT for acoustic voice analysis in total laryngectomized (TL) patients, although this software was designed for acoustic analysis of laryngeal voice. Recently, we have witnessed the development of specialized acoustic analysis software, Tracheoesophageal Voice Analysis (TEVA). This study aims to compare the analysis with both programs in TL patients. Methods: Observational analytical study of 34 TL patients where a quantitative acoustic analysis was performed for stable phonation with vowels [a] and [i] as well as spectrographic characterization using the TEVA and PRAAT software. Results: The Voice Handicap Index (VHI-10) showed a mean score of 11.29 ± 11.16 points, categorized as a moderate handicap. TEVA analysis found lower values in the fundamental frequency vs. PRAAT (p < 0.05). A significant increase in shimmer values was observed with TEVA (>20%). No significant differences were found between spectrographic analysis with TEVA and PRAAT. Conclusions: Tracheoesophageal speech is an alaryngeal voice, characterized by a higher degree of irregularity and noise compared to laryngeal speech. Consequently, it necessitates a more tailored approach using objective assessment tools adapted to these distinct features, like TEVA, that are designed specifically for TL patients. This study provides statistical evidence supporting its reliability and suitability for the evaluation and tracking of tracheoesophageal speakers.

The impact of previous endoscopic treatments on functional outcome after cricotracheal resection

OBJECTIVES

Treatment options for benign subglottic stenosis include endoscopic techniques or open surgery. Although endoscopic treatment is less invasive, a considerable proportion of patients develop recurrent stenosis. Endoscopic pretreatments do not exclude patients from a later surgical repair; however, the impact of previous endoscopic treatment attempts on functional outcome after open surgery is unknown.

METHODS

All patients, who received a cricotracheal resection (CTR) between January 2017 and June 2023 at the Department of Thoracic Surgery, Medical University of Vienna, were included in this retrospective study. Patient characteristics, surgical variables and postoperative outcome including a detailed functional assessment were analysed.

RESULTS

A total of 65 patients received a CTR during the study period, of which 40 were treatment naïve and 25 had a median of 2 (range 1-9) endoscopic pretreatments. Less-invasive voice-sparing CTR or standard CTR were more often possible in treatment-naïve patients. In contrary, pretreated patients regularly required extended procedures (P = 0.049). Three or more endoscopic treatments resulted in a significantly lower mean fundamental frequency (F0) after open repair (P = 0.048). In addition, a trend towards smaller mean sound pressure levels, a higher voice handicap index, higher impairments in RBH scores (roughness, breathing and hoarseness) and a higher dysphagia severity index was found in pretreated patients. The respiratory outcome after surgery was comparable between both groups.

CONCLUSIONS

Multiple endoscopic pretreatments lead to worse voice quality after CTR. The impact of prior endoscopic treatment before surgical repair should be considered when discussing treatment options with patients suffering from subglottic stenosis.

Validity, reliability and reproducibility of the VLS parameters form for the collection of videolaryngostroboscopic basic findings

OBJECTIVE

The videolaryngostroboscopy parameters form (VLSP form) is a diagnostic tool for the collection of videolaryngostroboscopic basic findings through the evaluation of 12 parameters. The aim of the present study is to preliminarily investigate intra- and inter-rater reliability, validity and responsiveness of the VLSP form.

METHODS

A study on a total amount of 160 forms for the evaluation of VLS basic findings was carried out. 80 forms were scored through the VLSP form and 80 with the Voice Vibratory Assessment with Laryngeal Imaging (VALI) form Stroboscopy (S) by four expert phoniatricians, that blindly scored the VLS recordings of 5 subjects without voice disorders and 5 patients with organic voice disorder before and after successful phonosurgery. Intra-rater and inter-rater analysis have been performed for both forms. The scores obtained through VLSP form and VALI form S have been compared to analyse concurrent validity, while VLSP scores before and after phonosurgery have been compared to analyse responsiveness. Finally, each rater annotated the "difficulty" in rating every parameter and its "importance" for the diagnosis.

RESULTS

The VLSP form showed good inter- and intra-rater reliability. It showed a good accuracy for the documentation of changes of laryngeal anatomy and function after phonosurgery, similarly to the VALI form S. The 12 parameters of the VLSP form were judged "Slightly Important" in 28.3% of the samples, "Very Important" in 64.8% of the samples, "Not Difficult" in 73.1% of the samples.

CONCLUSIONS

The results of the present study suggest that the VLSP form is comparable to the VALI form S for the evaluation of videolaryngostroboscopic parameters and is a valid, reliable and reproducible diagnostic tool. It can help voice clinicians in the evaluation of VLS examinations and it allows for a punctual assessment of modifications in laryngeal anatomy and function in pathological conditions and after phonosurgery.

Can We Use the Maximum Phonation Time as a Screening of Pulmonary Forced Vital Capacity in Post-COVID-19 Syndrome Patients?

OBJECTIVE

To verify the accuracy of the maximum phonation time of the vowel /a/ (MPT/a/), fricative /s/ (MPT/s/), number counting (MPTC), and number reached in this count (CN) to estimate forced vital capacity (FVC) in patients with post-COVID-19 syndrome.

METHOD

Cross-sectional study involving adult patients, who were admitted to the intensive care unit and referred to the Post-COVID-19 Rehabilitation Outpatient Clinic. Voice function was assessed using a Vocal Handicap Index (VHI) self-assessment questionnaire and MPT tests. To perform the phonatory tests, the patients remained in a standing posture and were instructed to inhale as much air as possible and, during a single exhalation, at usual pitch and loudness, sustain the emission of /a/ and /s/; and in another breath, to perform the ascending numerical count, starting from the number one up to the highest number they could reach. Pulmonary function was assessed by spirometry. The receiver operating characteristic (ROC) curve was plotted, and FVC values lower than the normal limit by Z-score (fifth percentile) were classified as impaired lung function. The predictive values and likelihood ratios were calculated.

RESULTS

A total of 70 patients participated, with 20-30% having a high VHI. Approximately 24% had an FVC impairment and significantly low values of MPT/a/, MPT/s/, MPTC, and CN. The test results showed overall accuracy of 70% and the cutoff points of 9.69, 6.78, 10.60, and 13, respectively, with high sensitivity, predictive negative value and low specificity, predictive positive value, and positive likelihood ratio.

CONCLUSIONS

Our results suggest that the MPT has moderate discriminatory power for FVC impairment, indicating that it is not a reliable indicator of pulmonary function in the population studied. Therefore, in patients with an MPT of less than 10.60 seconds, or a CN lower than 13, other criteria should be added to improve the diagnostic accuracy and support the decision to perform more complex investigations.

French-Language Adaptation of the Consensus Auditory-Perceptual Evaluation of Voice (CAPE-V)

OBJECTIVES

This study aimed to adapt the Consensus Auditory-Perceptual Evaluation of Voice (CAPE-V) protocol for perceptual voice assessment to the French language. The primary objective was to achieve consensus among an international panel of voice experts on the content of the adapted protocol.

METHODS

To ensure the relevance and robustness of the French CAPE-V protocol, this study employed a systematic Delphi method and involved an international panel primarily comprising speech therapists and lecturers from France and Belgium. The multi-stage process included an initial panel size of 15 experts. Three rounds of online questionnaires, integrating both quantitative and qualitative data collection, were conducted. Participants provided feedback and ratings on various protocol elements until a consensus was reached. Adaptations targeted the choice of task stimuli (sustained vowel, sentence reading, semi-spontaneous speech), of the rating scales, and vocal quality terminology.

RESULTS

The Delphi process achieved consensus on all elements of the adapted CAPE-V protocol. Notably, the sustained vowel task saw consensus in favor of the vowel /a/. Sentence adaptations achieved substantial agreement, with the final set unanimously approved. The simple Visual Analog Scale emerged as the preferred rating scale. Agreement on terms for describing vocal qualities marked a crucial step in establishing a shared vocabulary among French-speaking voice experts.

CONCLUSIONS

The study successfully adapted the CAPE-V protocol for perceptual voice assessment to the French language through a systematic Delphi process. The final protocol closely resembles the original English version, maintaining its structure and core objectives. Consensus on sustained vowel tasks, sentence adaptations, rating scales, and vocal quality terminology indicates the relevance and robustness of the adapted protocol. Ongoing validation studies in France demonstrate the potential clinical utility of the adapted CAPE-V in French-speaking contexts, representing a significant step toward standardized and validated voice assessment tools for clinicians and researchers globally.

Information conveyed by voice qualitya)

The problem of characterizing voice quality has long caused debate and frustration. The richness of the available descriptive vocabulary is overwhelming, but the density and complexity of the information voices convey lead some to conclude that language can never adequately specify what we hear. Others argue that terminology lacks an empirical basis, so that language-based scales are inadequate a priori. Efforts to provide meaningful instrumental characterizations have also had limited success. Such measures may capture sound patterns but cannot at present explain what characteristics, intentions, or identity listeners attribute to the speaker based on those patterns. However, some terms continually reappear across studies. These terms align with acoustic dimensions accounting for variance across speakers and languages and correlate with size and arousal across species. This suggests that labels for quality rest on a bedrock of biology: We have evolved to perceive voices in terms of size/arousal, and these factors structure both voice acoustics and descriptive language. Such linkages could help integrate studies of signals and their meaning, producing a truly interdisciplinary approach to the study of voice.

Accuracy Analysis of the Multiparametric Acoustic Voice Indices, the VWI, AVQI, ABI, and DSI Measures, in Differentiating between Normal and Dysphonic Voices

The study aimed to investigate and compare the accuracy and robustness of the multiparametric acoustic voice indices (MAVIs), namely the Dysphonia Severity Index (DSI), Acoustic Voice Quality Index (AVQI), Acoustic Breathiness Index (ABI), and Voice Wellness Index (VWI) measures in differentiating normal and dysphonic voices. The study group consisted of 129 adult individuals including 49 with normal voices and 80 patients with pathological voices. The diagnostic accuracy of the investigated MAVI in differentiating between normal and pathological voices was assessed using receiver operating characteristics (ROC). Moderate to strong positive linear correlations were observed between different MAVIs. The ROC statistical analysis revealed that all used measurements manifested in a high level of accuracy (area under the curve (AUC) of 0.80 and greater) and an acceptable level of sensitivity and specificity in discriminating between normal and pathological voices. However, with AUC 0.99, the VWI demonstrated the highest diagnostic accuracy. The highest Youden index equaled 0.93, revealing that a VWI cut-off of 4.45 corresponds with highly acceptable sensitivity (97.50%) and specificity (95.92%). In conclusion, the VWI was found to be beneficial in describing differences in voice quality status and discriminating between normal and dysphonic voices based on clinical diagnosis, i.e., dysphonia type, implying the VWI's reliable voice screening potential.

High and Wide: An In Silico Investigation of Frequency, Intensity, and Vibrato Effects on Widely Applied Acoustic Voice Perturbation and Noise Measures

OBJECTIVES

This in silico study explored the effects of a wide range of fundamental frequency (fo), source-spectrum tilt (SST), and vibrato extent (VE) on commonly used frequency and amplitude perturbation and noise measures.

METHOD

Using 53 synthesized tones produced in Madde, the effects of stepwise increases in fo, intensity (modeled by decreasing SST), and VE on the PRAAT parameters jitter % (local), relative average perturbation (RAP) %, shimmer % (local), amplitude perturbation quotient 3 (APQ3) %, and harmonics-to-noise ratio (HNR) dB were investigated. A secondary experiment was conducted to determine whether any fo effects on jitter, RAP, shimmer, APQ3, and HNR were stable. A total of 10 sinewaves were synthesized in Sopran from 100 to 1000 Hz using formant frequencies for /a/, /i/, and /u/-like vowels, respectively. All effects were statistically assessed with Kendall's tau-b and partial correlation.

RESULTS

Increasing fo resulted in an overall increase in jitter, RAP, shimmer, and APQ3 values, respectively (P < 0.01). Oscillations of the data across the explored fo range were observed in all measurement outputs. In the Sopran tests, the oscillatory pattern seen in the Madde fo condition remained and showed differences between vowel conditions. Increasing intensity (decreasing SST) led to reduced pitch and amplitude perturbation and HNR (P < 0.05). Increasing VE led to lower HNR and an almost linear increase of all other measures (P < 0.05).

CONCLUSION

These novel data offer a controlled demonstration for the behavior of jitter (local) %, RAP %, shimmer (local) %, APQ3 %, and HNR (dB) when varying fo, SST, and VE in synthesized tones. Since humans will vary in all of these aspects in spoken language and vowel phonation, researchers should take potential resonance-harmonics type effects into account when comparing intersubject or preintervention and postintervention data using these measures.