Metabolic Mechanisms of Vocal Fatigue

Vocal fatigue is among the most debilitating conditions affecting individuals with voice disorders. Impressions about mechanisms potentially underlying vocal fatigue have varied depending on how fatigue is defined, participants studied, and measures made, thereby impacting the selection of treatment strategies that may alleviate the condition. However, little is currently known about actual metabolic mechanisms of vocal fatigue. The current study aimed to address this issue by investigating the hypothesis that neuromuscular inefficiency, cardiovascular recovery deficits, or both, may play a role in fatigue. The approach replicated well-vetted approaches in exercise physiology. Metabolic profiles of subjects with vocal fatigue were assessed using gas exchange measures in comparison to two non-fatigue groups: vocally healthy and cardiovascular trained individuals, recruited based on results from a newly vetted questionnaire, the Vocal Fatigue Index (VFI) and laryngeal examination. Participants read out loud at two different loudness levels for a duration of 5 minutes for each task with periods of rest between tasks. Metabolic cost for and recovery time from reading were same across all groups. Oxygen uptake and recovery kinetics (EPOC), ratings of perceived exertion revealed interesting patterns in individuals with vocal fatigue compared to cardiovascular trained individuals in particular. Specifically, slow oxygen uptake kinetics in the vocal fatigue compared to the cardiovascular trained group pointed to utilization of anaerobic energy source to meet the demands of the reading task in the vocal fatigue group, suggesting neuromuscular inefficiency. In contrast, rapid oxygen uptake kinetics in the cardiovascular trained group pointed to utilization of aerobic energy sources and greater neuromuscular efficiency. Similarly, a greater number of individuals in vocal fatigue and vocally healthy groups showed an increase in oxygen consumption post reading (EPOC) compared to the cardiovascular trained group, indicating possible cardiovascular recovery deficits in the former groups. In addition to uncovering potential mechanisms underlying vocal fatigue, including neuromuscular inefficiency and cardiovascular recovery deficits, results from the present study highlight the potential importance of aerobic training to generate aerobic energy required for vocal task demands for both ease of task performance and recovery from it

Cross-Cultural Adaptation of the Brazilian Version of the Vocal Fatigue Index - VFI

The purpose of this study was to perform the cultural adaptation of the Brazilian version of the Vocal Fatigue Index (VFI). Two Brazilian bilingual speech-language pathologists (SLP) translated the original version of the VFI in English into Portuguese. The translations were reviewed by a committee of five voice specialist SLPs resulting in the final version of the instrument. A third bilingual SLP back-translated this final version and the same committee reviewed the differences from its original version. The final Portuguese version of the VFI, as in the original English version, was answered on a categorical scale of 0-4 indicating the frequency they experience the symptoms: 0=never, 1=almost never, 2=sometimes, 3=almost always, and 4=always. For cultural equivalence of the Portuguese version, the option not applicable was added to the categorical scale and 20 individuals with vocal complaints and dysphonia completed the index. Questions considered not applicable would be disregarded from the Brazilian version of the protocol; no question had to be removed from the instrument. The Brazilian Portuguese version was entitled Índice de Fadiga Vocal - IFV and features 19 questions, equivalent to the original instrument. Of the 19 items, 11 were related with tiredness of voice and voice avoidance, five concerned physical discomfort associated with voicing, and three were related to improvement of symptoms with rest or lack thereof. The Brazilian version of the VFI presents cultural and linguistic equivalence to the original instrument. The IFV validation into Brazilian Portuguese is in progress

Restructuring the Vocal Fatigue Index Using Mokken Scaling: Insights Into the Complex Nature of Vocal Fatigue

Vocal fatigue is a frequent symptom and a debilitating condition affecting individuals with voice disorders. In spite of the various attempts to define and quantify vocal fatigue, this complex trait has not been well understood. Mokken scaling was performed on the Vocal Fatigue Index (VFI) to develop a hierarchical understanding of the latent trait of vocal fatigue. Two hundred nine patients with voice disorders completed the VFI and provided the item responses necessary to complete the Mokken scaling. Results revealed a moderately strong Mokken scale and that the VFI presents a hierarchical structure to the underlying trait of vocal fatigue. Mokken scaling contributes to the ongoing investigation to the underlying construct of vocal fatigue and may provide additional information about specific complaints within the population of those with voice disorders

Equivalência cultural da versão brasileira do Vocal Fatigue Index – VFI

RESUMO O objetivo deste estudo foi desenvolver a equivalência cultural da versão brasileira do protocolo Vocal Fatigue Index – VFI. Dois fonoaudiólogos brasileiros bilíngues traduziram a versão original do VFI do inglês para o português. As traduções foram revisadas pelos pesquisadores e por um comitê de cinco fonoaudiólogos especialistas em voz, chegando-se a uma versão final do instrumento. Um terceiro fonoaudiólogo bilíngue retrotraduziu essa versão final e o mesmo comitê reviu as diferenças em relação à versão original. A versão final em português do protocolo VFI, assim como o original em inglês, é respondida de acordo com a frequência de ocorrência em que se experienciam os sintomas: 0 = nunca, 1 = quase nunca, 2 = às vezes, 3 = quase sempre e 4 = sempre. Para a equivalência cultural da versão em português, a opção “não aplicável” foi acrescida na chave de respostas e 20 indivíduos com queixa vocal e disfonia completaram o instrumento. Se alguma questão fosse considerada “não aplicável”, seria eliminada da versão brasileira do protocolo; nenhuma questão foi eliminada do instrumento. A versão em português brasileiro foi intitulada Índice de Fadiga Vocal – IFV e apresenta 19 questões, da mesma forma que o instrumento original. Dos 19 itens, 11 referem-se à fadiga e restrição vocal, 5, ao desconforto físico associado à voz e 3 à recuperação dos sintomas com o repouso. A versão para o português brasileiro do VFI apresenta equivalência cultural e linguística em relação ao instrumento original. A validação do IFV para o português brasileiro está em andamento

Vocal Fatigue Index: Validation and Cut-off Values of the Brazilian Version

Objectives: To complete the validation and to study the psychometric properties of the Brazilian Portuguese version of the Vocal Fatigue Index (IFV). Material and methods: This is a validation study of a diagnostic instrument utilizing a cross-sectional design and phases with quasi-experimental design. The total sample was composed of 212 participants, divided into two groups: Dysphonic Group and Vocally Healthy Group. All participants answered the VFI protocol. Data analysis consisted of the following steps: exploratory factor analysis, validity analysis, reliability analysis, sensitivity analysis, receiver operating characteristic, and area under the curve analysis. Results: The Brazilian Portuguese version of the VFI called Índice de Fadiga Vocal-IFV, has 17 items and four factors. The IFV is a valid, reliable and sensible instrument to measure the self-perception of vocal fatigue. The threshold values for each factor was: 4.50 for tiredness and voice impairment; 3.50 for avoidance of voice use; 1.50 for physical discomfort and 8.50 for improvement of voice symptoms with rest. The threshold value for the total score was 11.50. Conclusion: The Brazilian Portuguese version of the VFI is a valid instrument to assess the self-perception of vocal fatigue, especially in dysphonic individuals

Emotional and Physiological Responses of Fluent Listeners While Watching the Speech of Adults Who Stutter

Background: People who stutter produce speech that is characterized by intermittent, involuntary part-word repetitions and prolongations. In addition to these signature acoustic manifestations, those who stutter often display repetitive and fixated behaviours outside the speech producing mechanism (e.g. in the head, arm, fingers, nares, etc.). Previous research has examined the attitudes and perceptions of those who stutter and people who frequently interact with them (e.g. relatives, parents, employers). Results have shown an unequivocal, powerful and robust negative stereotype despite a lack of defined differences in personality structure between people who stutter and normally fluent individuals. However, physiological investigations of listener responses during moments of stuttering are limited. There is a need for data that simultaneously examine physiological responses (e.g. heart rate and galvanic skin conductance) and subjective behavioural responses to stuttering. The pairing of these objective and subjective data may provide information that casts light on the genesis of negative stereotypes associated with stuttering, the development of compensatory mechanisms in those who stutter, and the true impact of stuttering on senders and receivers alike. Aims: To compare the emotional and physiological responses of fluent speakers while listening and observing fluent and severe stuttered speech samples. Methods & Procedures: Twenty adult participants (mean age = 24.15 years, standard deviation = 3.40) observed speech samples of two fluent speakers and two speakers who stutter reading aloud. Participants\u27 skin conductance and heart rate changes were measured as physiological responses to stuttered or fluent speech samples. Participants\u27 subjective responses on arousal (excited-calm) and valence (happy-unhappy) dimensions were assessed via the Self-Assessment Manikin (SAM) rating scale with an additional questionnaire comprised of a set of nine bipolar adjectives. Outcomes & Results: Results showed significantly increased skin conductance and lower mean heart rate during the presentation of stuttered speech relative to the presentation of fluent speech samples (p\u3c0.05). Listeners also self-rated themselves as being more aroused, unhappy, nervous, uncomfortable, sad, tensed, unpleasant, avoiding, embarrassed, and annoyed while viewing stuttered speech relative to the fluent speech. Conclusions: These data support the notion that stutter-filled speech can elicit physiological and emotional responses in listeners. Clinicians who treat stuttering should be aware that listeners show involuntary physiological responses to moderate-severe stuttering that probably remain salient over time and contribute to the evolution of negative stereotypes of people who stutter. With this in mind, it is hoped that clinicians can work with people who stutter to develop appropriate coping strategies. The role of amygdala and mirror neural mechanism in physiological and subjective responses to stuttering is discussed

Cross-Cultural Adaptation and Validation of the Vocal Fatigue Index into Persian

Introduction: The aim of the present study was the cross-cultural adaptation and validation of the Vocal Fatigue Index (VFI) in Persian. Methods: The English version of the VFI was translated to Persian using the guidelines of International Quality of Life Assessment. Eighty participants with voice disorders and 50 healthy controls without any voice disorders completed the Persian version of the VFI. The 80 participants with voice disorders completed the VFI a second time a week from the initial completion to evaluate test-retest reliability. Results: The VFI measure demonstrated a strong internal consistency. Cronbach alpha coefficient was 0.95 for tiredness and avoidance of voice use, 0.86 for physical discomfort and 0.83 for improvement or lack thereof of symptoms with voice rest. VFI also showed a high test-retest reliability (r = 0.75–0.89). Conclusions: The Persian version of the VFI is considered to be a valid and reliable questionnaire for identifying individuals with probable vocal fatigue. The VFI can be utilized in clinics across Iran in the assessment and treatment of individuals with vocal fatigue