Eric James Hunter

• Ph.D.
• Professor and Chair at University of Iowa

Introduction: The Acoustic Voice Quality Index (AVQI) and smoothed Cepstral Peak Prominence (CPPs) have been reported to effectively support the assessing of voice quality in persons seeking voice care across many languages. This study aims to evaluate the diagnostic accuracy of these two measures in detecting voice disorders in American English sp...

Purpose This scoping review aimed to explore the use of volitional voice tasks in assessing swallowing-related outcomes and to evaluate their therapeutic impact on swallowing disorders, including their effects on swallowing biomechanics. Method This scoping review was conducted following the Preferred Reporting Items for Systematic Reviews and Met...

Introduction. Auditory feedback allows individuals to monitor their vocal characteristics and adjust to maintain optimal voice quality. One type of auditory stimulation for conversational voice training/therapy is pure tone stimulation. This technique presents binaural auditory stimuli consisting of pure tones separated by half-step intervals to mo...

Objective: This study examines factors predicting self-reported voice symptoms in call center workers. Methods: Multivariate analysis and predictive modeling assess personal, work-related, acoustic, and behavioral factors. Generalized Linear Models (GLMs) and Receiver Operating Characteristic (ROC) curves are employed. Results: Age and sleep patt...

In speech production research, talkers often perform a speech task several times per recording session with different speaking styles or in different environments. For example, Lombard speech studies typically have talkers speak in several different noise conditions. However, it is unknown to what degree simple repetition of a speech task affects s...

Purpose: This study examined the immediate acoustic, auditory-perceptual, and self-perceptual effects of two semi-occluded vocal tract exercises (SOVTs): straw phonation and straw phonation into a cup of water, delivered in a remote setting. Method: 36 participants (19 females and 17 males) completed a baseline battery of acoustic recordings, fo...

Background: While several acoustic voice metrics are available for clinical voice assessment, there remains a significant need for reliable and ecologically valid tools. The Acoustic Voice Quality Index version 03.01 (AVQI-3) and Acoustic Breathiness Index (ABI) hold potential due to their comprehensive assessment approach, incorporating diverse vo...

Objectives: This pilot study aimed to identify and test a battery of time-efficient and cost-effective voice and swallowing screening tools for post-extubated patients in Chile. Methods: A panel of four experts selected and rated voice and swallowing screening tools. Seven measures were selected: smoothed cepstral peak prominence (CPPS) and maximu...

The field of voice disorders lost a true pioneer with the passing of Dr. Cristina Jackson-Menaldi (June 21, 1950 - November 20, 2020). A renowned voice pathologist and singing voice specialist, Dr. Jackson-Menaldi made significant contributions to our understanding and treatment of voice disorders. She was also a passionate advocate for voice educa...

Purpose: With the significant and growing interest in voice disorders among teachers over the last several decades, there is value in having a comprehensive overview of the current state of the field and its related research productivity. This study aims to provide an updated and comprehensive mapping of the intellectual structure and research evo...

Purpose: Considering the conceptual migration from vocal load and vocal loading to vocal demand and vocal demand response, this review of literature aims to identify physiological explanations, reported measurements, and associated factors (vocal demands) reported in the literature when considering the phonatory response to a vocal demand. Method...

Digital inclusion (DI) represents a framework for educational leaders to address ongoing digital access and participation divides for adult caretakers (e.g., parents) of school-aged children, as schools continue adopting new education technology tools. This preliminary research investigates teacher perceptions of different DI needs for parents duri...

While acoustic speech analysis is non-invasive, the utility has been mixed due to the range of voice types. For vocal health practitioners to efficiently and quickly assess and document voice changes, knowing which voice parameter would be sensitive to vocal change is crucial. Using a database of 296 individual voices including 8 voice pathology ty...

The ability to perform high-pitched and loud tasks have been associated with lower risks of penetration and aspiration in people with oropharyngeal dysphagia (OD). Previous studies suggest that these two vocal tasks may improve swallowing-related kinematics; laryngeal elevation and glottic closure. This study aims to identify which types of vocal e...

School teachers have an elevated risk of voice problems due to the vocal demands in the workplace. This presentation summarizes the results of several studies investigating voice use in real and simulated classroom settings. The first study used 57 teachers, who were monitored all day for 2 weeks in teaching and nonteaching environments. In the sec...

Vocal effort is the most common symptom that in patients with voice disorders and decreasing vocal effort is often a therapeutic goal. Previous studies indicate that a vocal effort goal can elicit voice production with very similar acoustic parameters. The purpose of this study is to clarify the effort and acoustic parameter dependencies on differe...

While vocal pathology can elevate vocal effort, communication situations also have an effect. Previous work on vocal effort and communication situations have relied on listener ratings of effort rather than talker-centric vocal effort. Towards that end, in this study, talker-centric vocal effort was related to different communication demands. Addit...

Background: College professors expose themselves to different vocal demands during teaching. During the COVID-19 pandemic, college professors were exposed to extra working loads associated with working from home, with less-than-optimal acoustic conditions. This is the reason why it was needed to think of easy-to-implement and low-cost solutions for...

School teachers’ voice problems are widespread and influence the learning process. Voice amplification systems in classrooms are a common response and a preventative strategy. The primary purpose of this study was to (1) determine the relationship between teacher vocal fatigue and use of classroom amplification; and (2) identify factors influencing...

Voice and swallowing share neural and musculoskeletal substrates, with emerging literature demonstrating that specific phonatory tasks may predict swallowing outcomes and elicit positive changes for swallowing rehabilitation. This proof-of-concept pilot study aimed to explore the effects of semi-occluded vocal tract exercises (SOVTE) on swallowing-...

Objective Body posture is a commonly discussed component of voice training and therapy. However, body postures, postural changes, related posturing muscle monitoring, and the potential changes in voice production (eg, glottal aerodynamic changes, acoustic differences) have been inconsistently described in the literature, leaving room for free inter...

Background: Due to elevated vocal health risk in industries such as call centers, there is a need to have accessible and quick self-report tools for voice symptoms. This study aimed to determine if the concurrent and construct validity of three visual analog scales (VASs) of voice quality and symptoms could be used as a screening tool in call cent...

Background: Voice disorders among teachers are widespread. Teachers’ voice problems have been shown to influence the teaching-learning process, thereby impeding students’ academic performance. Voice amplification has been used as a preventative strategy to avoid voice problems and as a means of augmenting student reception of a teacher’s voice. How...

Objectives: The optimization of vocal effort given a response to a voice demand is a common clinical and vocal performance goal. Increases in vocal effort are often in response to communication limitations from both the interlocutors and the communication environment. This study investigates the relationship between vocal effort and vocal demands...

Purpose An elevated sense of vocal effort due to increased vocal demand is frequently reported by patients with voice disorders. However, effects of vocal warm-up on self-assessed vocal effort have not been thoroughly examined. A recently developed version of the Borg CR-10 Scale facilitates vocal effort assessments, following different vocal warm-...

Voice-activated systems are integrated into a variety of desktop, mobile, and Internet-of-Things (IoT) devices. However, voice spoofing attacks, such as impersonation and replay attacks, in which malicious attackers synthesize the voice of a victim or simply replay it, have brought growing security concerns. Existing speaker verification techniques...

COVER ILLUSTRATION Neural changes accompanying dosage intensive treatments targeting voice or articulation in patients with Parkinson's dysphonia. Voice treatment (yellow) targeted larynx and respiration while articulation treatment (blue) targeted mouth and lips. Behaviorally, voice treatment but not articulation treatment resulted in improvement...

This study compared acoustic and neural changes accompanying two treatments matched for intensive dosage but having two different treatment targets (voice or articulation) to dissociate the effects of treatment target and intensive dosage in speech therapies. Nineteen participants with Parkinsonian dysphonia (11 F) were randomized to three groups:...

To increase the reliability and comparability of vocal loading studies, this paper proposes the use of a standardized approach with experiments that are [1] grounded on consistent definitions of terms related to vocal fatigue (vocal effort, vocal demand, and vocal demand response), and [2] designed to reduce uncertainty and increase repeatability....

Objective A case study was used to determine which acoustic parameters would be sensitive to a SOVT-based vocal warm-up over the duration of a standard voice treatment. Methods The longitudinal research design consisted of repeated voice measures during 7 weeks from a single subject, a 48-year-old male occupational voice user with a history of voi...

Since swallowing and phonation share the same structures, it is becoming more common in the clinical context to use certain strategies linked to vocal therapy for swallowing therapy. Still, these possible relationships and their possible implications have not been thoroughly studied integrally. This scoping review aims to analyze the literature abo...

Objective: Examine speech rate and muscle function in athletes with and without sports related concussion (SRC). Methods: Over 1,110 speech samples were obtained from 30, 19-22 year-old athletes who had sustained an SRC within the past 2 years and 30 pair-wise matched control athletes with no history of SRC. Speech rate and muscle function were eva...

This study aims to identify trends in scientific publications on voice disorders among teachers through a bibliometric analysis. The Web of Science Core Collection (WoSCC) was used to search for information related to voice disorders and teachers between 2000 and 2021. Bibliometric data and co-occurrence mapping were obtained through Clarivate Anal...

The purpose of this study was to determine the short-term effect over time on acoustic voice parameters after a short routine of water-resistance voice therapy (WRT) as a vocal warm-up. A secondary objective was to determine trends of change in voice metrics over time. Longitudinal repeated-measures research design case study which consisted of re...

Objectives: 1. define the occurrence of work-related hearing problems and voice disorders among teachers that have contacted the Colombian National Board of Disability Assessment (NBDA) for follow-up; 2. identify individual associated factors of hearing problems and voice disorders among teachers; 3. assess the limitations and restrictions due to h...

Aims: (1) Determine the difference in vocal fry phonation in English and Spanish productions among bilingual young adults, (2) Characterize the effect of spoken language and native language on vocal fry production among English-Spanish bilingual speakers, (3) Identify the effect of first and second language knowledge of the listener in the voice p...

Introduction Voice teachers use anecdotal evidence and experience in determining the appropriateness of repertoire for each student's development. Tessitura is important in that determination, but until recently a straightforward, repeatable, and quantifiable method for determining tessitura has not existed. However, technology exists to provide th...

INTRODUCTION: Respiratory and extrinsic laryngeal muscles are essential for phonation, contributing to subglottal pressure generation and laryngeal stability. Respiratory and extrinsic laryngeal muscles may be affected by postural changes and are often used by voice teachers and clinicians as a strategy to promote more optimal and healthy voice pro...

Background Speaking a second language influences jitter and shimmer when comparing monolingual English speakers with bilingual English-Spanish speakers. However, there is little information about differences on voice acoustic parameters when comparing monolingual Spanish speakers with bilingual Spanish-English speakers during their productions in S...

Purpose Patients with voice problems commonly report increased vocal effort, regardless of the underlying pathophysiology. Previous studies investigating vocal effort and voice production have used a range of methods to quantify vocal effort. The goals of the current study were to use the Borg CR100 effort scale to (a) demonstrate the relation betw...

The physical production of speech level dynamic range is directly affected by the physiological features of the speaker such as vocal tract size and lung capacity; however, the regulation of these production systems is affected by the perception of the communication environment and auditory feedback. The current study examined the effects of room a...

No PDF available ABSTRACT Mobile voice recording has been a staple of voice research, providing an authentic representation of speech outside a controlled environment; however, mobile recordings increase uncertainty with potential environmental sound contamination, as well as speech production differences due to variations in environment, purpose,...

Establishing a link between physical properties and vocal effort.

Purpose Vocal fatigue (VF) is a primary vocal symptom experienced by professional voice users, such as teachers, whose voice is an occupational tool. The study determines the utilization of the Vocal Fatigue Index (VFI), a 19-item scale in identifying symptoms of VF and its severity in teachers. Methods Using responses of 695 teachers who complete...

Purpose Vocal effort has been of increasing interest to voice clinicians and researchers. However, little is known about the prevalence of vocal effort in voice patients presenting to voice clinics. The purpose of this study was to better understand how vocal effort is understood and used in a clinical setting, including the current opinions on thi...

Aim: the purpose of this study was to translate and adapt the English version of the Vocal Fatigue Index (VFI) into the Spanish language. Methods: the English version of the Vocal Fatigue Index (VFI) was translated into Spanish by two bilingual speech-language pathologists, and then was back-translated into English. The Spanish VFI (o “Índice de F...

A preliminary analysis of teachers' open-ended responses to questions about voice amplification use in the classroom

No PDF available ABSTRACT Acoustic and perceptual research has shown that an individual's vocal characteristics change over time [e.g., Harnsberger et al., J. Voice 22(1), 2334–2350 (2008)]. Most previous studies have investigated speech changes over time using cross-sectional data. The present study is a later-life longitudinal investigation of th...

No PDF available ABSTRACT When communication occurs in noise or with hearing-impaired listeners, talkers often modify their speech. Speech produced in noise, or “Lombard speech,” and speech produced by talkers instructed to speak as though their communication partner has a hearing loss, or “clear speech,” usually feature a reduced speaking rate and...

Background Teachers have been found to have a higher than normal risk to develop voice disorders. One common symptom of voice problems among teachers is the report and occurrence of vocal fatigue, often associated with different individual, physical, environmental, and professional factors. Aim The aim of this study was to provide insight into the...

Objective: To examine speech rate and muscle function in athletes with and without sports related concussion (SRC). Methods: We recruited 30 athletes aged 19-22 years-old who had sustained a SRC within the past 2 years and 30 pair-wise matched controls with no history of SRC from the student community at Michigan State University. Speech rate and m...

Purpose The purpose of this document is threefold: (a) review the uses of the terms “vocal fatigue,” “vocal effort,” “vocal load,” and “vocal loading” (as found in the literature) in order to track the occurrence and the related evolution of research; (b) present a “linguistically modeled” definition of the same from the review of literature on the...

Purpose Studies of the respiratory and laryngeal actions required for phonation are central to our understanding of both voice and voice disorders. The purpose of this tutorial is to highlight complementary insights about voice that have come from the study of vocal tract resonance effects. Conclusion This tutorial overviews the following areas: (...

In the past, several room-acoustic parameters, recommendations, and standards have been developed with emphasis on accommodating the listener. Recent research has shown that talkers also respond to room acoustics via vocal adaptations. In fact, room acoustics may influence the development of voice disorders in occupational speech users. To evaluate...

A ferroelectret nanogenerator (FENG) was recently developed as a flexible energy harvesting device with bi-directional capability between electrical and mechanical energy domains, and its use as a loudspeaker/microphone was demonstrated. Dependencies of Sound Pressure Levels (SPLs) generated by FENG due to an AC voltage stimulus, surface area, geom...

No PDF available ABSTRACT Physiological processes involving speech anatomical structures change with age and affect voice and speech production. Additionally, those with high voice demand (e.g., singers, teachers, coaches) have also demonstrated voice and speech production related changes. From a listener’s perspective, speech changes can be used t...

Background: In addition to language differences in fundamental frequency between bilinguals and monolinguals, studies have also included other acoustic parameters to analyze differences in voice production associated with the language spoken. Aim: To identify differences in voice acoustic parameters during English productions between monolingual...

There are various professions whose main tool for performing their work is the voice. An example is teachers, who during their work day, in addition to using their voice for prolonged periods, are exposed to working conditions that can influence both positively and adversely their general health, since in addition to the voice, they present patholo...

The purpose of this study was to investigate the gender differences in voice simulation using a sensitivity analysis approach. A global, Monte Carlo-based approach was employed, and the relationships between biomechanical inputs (lung pressure and muscle activation levels) and acoustic outputs (fundamental frequency, f0, and sound pressure level, S...

Occupational speech users such as schoolteachers develop voice disorders at higher rates than the general population. Previous research has suggested that room acoustics may influence these trends. The research reported in this paper utilized varying acoustical conditions in a reverberant room to assess the effects on vocal parameters of healthy ta...

Introduction: Females face a significantly higher risk of presenting with voice problems than males. This discrepancy has been associated with a number of differences in respiratory behavior and the physiology of the laryngeal and endocrine systems. Methods: In conjunction with established spirometry measures, the Vocal Fatigue Index (VFI) was u...

Introduction: Computer analysis of voice recordings is an integral part of the evaluation and management of voice disorders. In many practices, voice samples are taken in rooms that are not sound attenuated and/or sound-proofed; further, the technology used is rarely consistent. This will likely affect the recordings, and therefore, their analyses...

Purpose: To explore the short-term effect of work-related voice use on voice function, and noise exposure on hearing function among radio broadcasters. Method: A 1-week follow-up study with the participation of two radio broadcasters was conducted. Participants were monitored at the beginning and at the end of the working week. Premonitoring assess...

The current study investigated whether the extent of second formant (F2) transitions differentiate children who stutter from fluent peers and children who recover from stuttering. We hypothesized that children with persistent stuttering would produce smaller F2 extents than children who eventually recover from stuttering and children who do not stu...

In both audiology and speech-language pathology, as well as in speech and hearing science research, the space where the work is done is an integral part of the function. Hence, for all of these endeavors, it can be important to measure the acoustics of a room. This article provides a tutorial regarding the measurement of room reverberation and back...

Occupational voice users have a heightened risk of voice problems. There are many potential causes of this increased vocal risk, including poor room acoustics (e.g., excessively high or low reverberation times). Whether a school teacher working in a loud or poorly designed classroom or a singer working in both stage and studio conditions, with incr...

Introduction: The diagnoses of voice disorders, as well as treatment outcomes, are often tracked using visual (eg, stroboscopic images), auditory (eg, perceptual ratings), objective (eg, from acoustic or aerodynamic signals), and patient report (eg, Voice Handicap Index and Voice-Related Quality of Life) measures. However, many of these measures a...

Although vocal dosimeters are often used for long-term voice monitoring, the uncertainty of the quantities measured by these devices is not always stated. In this study, two common vocal dosimetry quantities, mean vocal sound pressure level and mean vocal fundamental frequency, were measured by four vocal dosimeters (VocaLog2, VoxLog, Voice Care, a...

Speech production can differ depending on how speech is elicited (e.g., spontaneous speech, read text, speaking style instructions, the speaking environment). Previous studies have shown different speaking styles being elicited via instruction (e.g., clear speech) or via the speaking environment (e.g., Lombard speech). There is evidence that the ac...

Objective: Previous research has concluded that teachers are at a higher-than-normal risk for voice issues that can cause occupational limitations. While some risk factors have been identified, there are still many unknowns. Patients and methods: A survey was distributed electronically with 506 female teacher respondents. The survey included que...

Objectives Occupational voice users report higher instances of vocal health problems. Women, who are more likely than men to report voice problems, are the largest members of some occupational voice users, such as teachers. While a common complaint among this population is vocal fatigue, it has been difficult to quantify. Therefore, the goal of thi...

Speech production can differ depending on how speech is elicited (e.g. spontaneous speech, read text, speaking style instructions, the speaking environment). In most studies in which different speaking styles have been elicited via instruction (e.g., clear speech) or via the speaking environment (e.g., Lombard speech), the talkers have read printed...

Purpose: Vocal fry is increasingly used in everyday speech. The purpose of this study was to identify associated factors of vocal fry among young US college-age students. Methods: Forty college students participated in a cross-sectional study. Participants produced speech under nine different room acoustic conditions (simulated). The recorded sp...

Conversational speech produced in noise can be characterised by increases in intelligibility relative to such speech produced in quiet. Listening difficulty (LD) is a metric that can be used to evaluate speech transmission performance more sensitively than intelligibility scores in situations in which performance is likely to be high. The objective...

Public school teachers have a heightened risk of voice problems. There are many potential causes of this increased vocal risk, including poor room acoustics (e.g., excessively high or low reverberation times). With increased understanding, rooms could be better designed to maintain communication transfer (intelligibility), while mitigating unhealth...

As a person ages, the acoustic characteristics of the voice change. Understanding how the sound of a voice changes with age may give insight into physiological changes related to vocal function. Previous work has shown changes in acoustical parameters with chronological age, as well as differences between listener-perceived age and chronological ag...

Previous studies on the influence of noise in the classroom on the hearing function of teachers have primarily focused either on physical education teachers or music teachers. However, the influence of classroom noise on hearing difficulties among teachers is largely unknown. The aim of this study was to assess the association between classroom noi...

The overuse of the voice by professional voice users, such as teachers, is known to cause physiological vocal fatigue. Vocal fatigue is used to denote negative vocal adaptation that occurs as a consequence of prolonged voice use or vocal load. This study investigates how self-reported vocal fatigue is related to voice parameters (sound pressure lev...

Previous research has concluded that teachers are at higher than normal risk for voice issues that can cause occupational limitations. While some risk factors have been identified, there are still many unknowns. To gain more understanding regarding some of these unknowns, a self-reported survey was distributed electronically with more than 500 fema...