Vocal Fold Vibratory Dose and Perceived Exertion Responses to the Fluid Interval Test for Voice (FIT-V): A Novel Vocal Loading Task Platform.

INTRODUCTION: Vocal loading tasks are often used to study how specific variables influence downstream vocal effort or fatigue. The current study introduces a novel vocal loading task, the Fluid Interval Test for Voice (FIT-V) that combines laryngeal diadochokinesis, intervallic rest and exercise, and fluid back pressure. To assess the differences between this novel task and existing vocal loading tasks, we measured vocal fold vibratory dose and perceived phonatory exertion across three 30-minute task conditions: a control loud oral reading task (LOR), a back pressure-resisted Fluid Interval Test for Voice (FIT-V5), and an unresisted Fluid Interval Test for Voice (FIT-V0). METHODS: Following a training session, 30 participants completed the three tasks (LOR, FIT-V0, and FIT-V5) in counterbalanced order on different days. Vocal fold cycle (Aim 1A) and distance doses (Aim 1B) were collected continuously using a dosimeter. The overall perceived phonatory exertion (Aim 2A) was rated once per minute, while anatomically localized cognitive, laryngeal, thoracic, abdominal, and articulatory exertion (Aim 2B) were rated once at the end of each task. Statistical analyses examined the effects of task and task× time interactions on the dependent variables. RESULTS: The FIT-V0 and FIT-V5 tasks imposed smaller vocal fold cycle doses (P < 0.001; Aim 1A) and distance doses (P < 0.001; Aim 1B) than the LOR task while eliciting comparable or greater magnitudes of overall perceived phonatory exertion (P = 0.003; Aim 2A). However, anatomically localized perceived exertion was greater in the abdomen and thorax (P < 0.05) and lesser in the anterior neck (P < 0.05) in the two FIT-V tasks relative to the LOR task (Aim 2B). Absolute forced vital capacity was a significant predictor of most forms of anatomically localized perceived exertion. DISCUSSION: The unresisted FIT-V0 and the back pressure-resisted FIT-V5 tasks yielded similar profiles of overall perceived phonatory exertion, despite vocal fold vibratory doses roughly half that of the LOR task. However, the anatomically localized perceived exertion data underscored subtle across-task differences not apparent in the overall ratings, suggesting potentially distinct physiological and perceptual niches for the three task protocols.

Effects of Back Pressure on the Feasibility and Tolerability of Laryngeal Diadochokinetic Exercise: A Pilot Study.

BACKGROUND: The term vocal demand response refers to how speakers meet vocal demands. Vocal loading tasks with predetermined demand parameters (duration, pitch, loudness, etc) have been used in research to study the vocal demand response; these have historically consisted of loud sustained vowel and loud speech tasks. Tasks founded on laryngeal diadochokinesis (LDDK) may be viable alternatives, especially if demand parameters such as exercise-rest ratio and fluid back pressure are concurrently modulated. OBJECTIVES: To explore the effects of four fluid back pressure conditions (0, 5, 10, and 15 cm H2O) on several measures of subjective participant experience, feasibility, and tolerability during intervallic laryngeal diadochokinetic exercise. METHODS: Participants (n = 12) completed 15-minute trials of LDDK in 30-second rest and exercise intervals against four counterbalanced back pressure conditions: 0, 5, 10, and 15 cm H2O. The effects of back pressure on (1) ratings of perceived vocal exertion, (2) prevalence of adverse effects such as shortness of breath or lightheadedness, (3) subjective difficulty of sustaining LDDK, (4) number of exercise intervals completed, (5) rankings of participant-preferred back pressure levels, and (6) expert ratings of auditory-perceptual diadochokinetic strength were assessed descriptively. RESULTS: Perceived vocal exertion, lightheadedness, and subjective laryngeal diadochokinetic difficulty increased as back pressure increased. Number of intervals completed, auditory-perceptual diadochokinetic strength, and participant rankings of back pressure conditions, by contrast, decreased as back pressure increased. 0 and 5 cm H2O were the most preferred back pressure conditions overall. DISCUSSION: Fluid back pressure was feasible and broadly tolerated during 15-minute trials of vocal exercise. However, the transition from 5 → 10 cm H2O appeared to represent an inflection point in our results: a minority of participants did not tolerate exercise at 10 cm H2O, becoming a majority at 15 cm H2O. We conclude that fluid back pressure should be restricted to values between 0 and 10 cm H2O during LDDK.

Initial Theoretical Discussion of Identity as Barrier and Facilitator in Voice Habilitation and Rehabilitation.

OBJECTIVES: The purpose of this paper is to review seminal identity theories grounded in social psychology and one concept from voice science and explain how this group may point to identity factors facilitating or impeding voice habilitation and rehabilitation. METHODS: Identity theories from the social psychology literature (Dramaturgical Theory, Self-Categorization Theory, Self-Determination Theory, Identity Negotiation Theory) and vocal congruence are described. Concepts are synthesized with voice science research to explore potential identity-behavior relations at play in voice habilitation and rehabilitation. RESULTS: Applicable concepts from social psychology and voice science suggest identity-related processes by which a client may or may not develop a voice difference/disorder, seek intervention, and achieve goals in intervention. A bidirectional relationship between identity and behavior has been well-established in the social psychology literature. However, the relevance of vocal behavior has yet to be formally examined within this literature. Importantly, although connections between behavioral tendencies and voice disorders as well as the contribution of identity to gender-affirming voice treatment have been established in the voice science literature, the consideration of identity's possible role in voice habilitation and rehabilitation in cis gender individuals has thus far been scant. CONCLUSIONS: Research into identity and voice habilitation and rehabilitation may help to improve voice intervention outcomes. A possible adjunct to human studies is agent-based modeling or other computational approaches to assess the myriad factors that may be relevant within this line of inquiry.

The Influence of Multisensory Input On Voice Perception and Production Using Immersive Virtual Reality.

OBJECTIVES: The purpose was to examine the influence of auditory vs visual vs combined audiovisual input on perception and production of one's own voice, using immersive virtual reality technology. METHODS: Thirty-one vocally healthy men and women were investigated under 18 sensory input conditions, using immersive virtual reality technology. Conditions included two auditory rooms with varying reverberation times, two visual rooms with varying volumes, and the combination of audiovisual conditions. All conditions were repeated with and without background noise. Speech tasks included counting, sustained vowel phonation, an all-voiced sentence from the Consensus Auditory-Perceptual Evaluation of Voice, and the first sentence from the Rainbow Passage, randomly ordered. Perception outcome measures were participants' self-reported perceptions of their vocal loudness, vocal effort, and vocal comfort in speech. Production outcome measures were sound pressure level (SPL) and spectral moments (spectral mean and standard deviation in Hz, skewness, and kurtosis). Statistical analyses used self-reported vocal effort, vocal loudness, and vocal comfort in percent (0 = "not at all," 100 = extremely), SPL in dB, and spectral moments in Hz. The reference level was a baseline audiovisual deprivation condition. RESULTS: Results suggested (i) increased self-perceived vocal loudness and effort, and decreased comfort, with increasing room volume, speaker-to-listener distance, audiovisual input, and background noise, and (ii) increased SPL and fluctuations in spectral moments across conditions. CONCLUSIONS: Not only auditory, but also visual and audiovisual input influenced voice perception and production in ways that have not been previously documented. Findings contribute to the basic science understanding the role of visual, audiovisual and auditory input in voice perception and production, and also to models of voice training and therapy. The findings also set the foundation for the use of virtual reality in voice and speech training, as a potentially power solution to the generalization problem.

Comparative Analysis of Two Methods of Perceptual Voice Assessment.

OBJECTIVES: The primary aim was to compare two methods for perceptual evaluation of voice - paired comparison (PC) and visual analog scale (VAS) ratings. Secondary aims were to assess the correspondence between two dimensions of voice- overall severity of voice quality and resonant voice, and to investigate the influence of rater experience on perceptual rating scores and rating confidence scores. STUDY DESIGN: Experimental design. METHODS: Voice samples from six children (pre and post therapy) were rated by 15 Speech-Language Pathologists specialized in voice. Raters completed four tasks corresponding to the two rating methods and voice qualities: PC-severity, PC-resonance, VAS-severity, and VAS-resonance. For PC tasks, raters chose the better of two voice samples (better voice quality or better resonance, depending on the task) and indicated the degree of confidence in each choice. Rating and confidence score were combined to produce a number on a 1-10 scale (PC-confidence adjusted). VAS ratings involved rating voices on a scale for degree of severity and resonance, respectively. RESULTS: PC-confidence adjusted and VAS ratings were moderately correlated for overall severity and also vocal resonance. VAS ratings were normally distributed and had greater rater consistency than PC-confidence adjusted ratings. VAS scores reliably predicted binary PC choices (choice of voice sample only). Overall severity and vocal resonance were weakly correlated and rater experience was not linearly related to rating scores or confidence. CONCLUSIONS: Results suggest that the VAS rating method holds advantages over PC, including normally distributed ratings, superior consistency of ratings, and the ability to provide more finely grained detail regarding the auditory perception of voice. Overall severity and vocal resonance were not redundant in the current data set, suggesting that resonant voice and overall severity are not isomorphic. Finally, the number of years of clinical experience was not linearly related to perceptual ratings or rating confidence.

Effects of divided attention on swallowing in healthy participants.

Swallowing impairments are treated mostly behaviorally. It is requisite to understand the relationship of cognition, specifically attention, with swallowing since so many swallowing impairments occur concomitantly with cognitive disorders. This study examined the hypothesis that attentional resources are required during swallowing. The approach involved a dual-task, reaction time (RT) paradigm in ten healthy, nonimpaired participants. Baseline measures were obtained of the duration of the anticipatory phase and of the oropharyngeal phase of swallowing and the RTs to nonword auditory stimuli. A dual-task then required participants to swallow 5 ml of water from an 8-oz. cup while listening for a target nonword presented auditorily during the anticipatory or the oropharyngeal phase. Target stimuli were randomized across baseline and dual-task trials. Duration of the anticipatory phase and of the oropharyngeal phase of swallowing and duration of the RT baseline trial and of the dual-task trial were determined. Results showed a statistically significant increase in speed of the anticipatory phase, relative to the oropharyngeal phase, for swallowing during the dual-task. RTs were slowed for both the anticipatory and the oropharyngeal phase during the dual-task, although neither of these was statistically significant. Clinical implications of these data suggest that disruptive stimuli in the environment to nonimpaired individuals may alter feeding but have little effect on the oropharyngeal swallow.

Developmental Changes in the Perception of Vocal Loudness and Voice Quality in 3- to 6-Year-Old Children.

PURPOSE: The study's primary aim was to investigate developmental changes in the perception of vocal loudness and voice quality in children 3-6 years of age. A second aim was to evaluate a testing procedure-the intermodal preferential looking paradigm (IPLP)-for the study of voice perception in young children. METHOD: Participants were categorized in two age groups: 3- to 4-year-olds and 5- to 6-year-olds. Children were tested remotely via a Zoom appointment and completed two perceptual tasks: (a) voice discrimination and (b) voice identification. Each task consisted of two tests: a vocal loudness test and a voice quality test. RESULTS: Children in the 5- to 6-year-old group were significantly more accurate than children in the 3- to 4-year-old group in discriminating and identifying differences between voices for both loudness and voice quality. The IPLP, used in the identification task, was found to successfully detect differences between the age groups for overall accuracy and for most of the sublevels of vocal loudness and voice quality. CONCLUSIONS: Results suggest that children's ability to discriminate and identify differences in vocal loudness and voice quality improves with age. Findings also support the use of the IPLP as a useful tool to study voice perception in young children.

The Effect of Microphone Frequency Response on Spectral and Cepstral Measures of Voice: An Examination of Low-Cost Electret Headset Microphones.

PURPOSE: The purpose of this study was to establish the frequency response of a selection of low-cost headset microphones that could be given to subjects for remote voice recordings and to examine the effect of microphone type and frequency response on key acoustic measures related to voice quality obtained from speech and vowel samples. METHOD: The frequency responses of three low-cost headset microphones were evaluated using pink noise generated via a head-and-torso model. Each of the headset microphones was then used to record a series of speech and vowel samples prerecorded from 24 speakers who represented a diversity of sex, age, fundamental frequency (F o), and voice quality types. Recordings were later analyzed for the following measures: smoothed cepstral peak prominence (CPP; dB), low versus high spectral ratio (L/H ratio; dB), CPP F o (Hz), and cepstral spectral index of dysphonia (CSID). RESULTS: The frequency response of the microphones under test was observed to have nonsignificant effects on measures of the CPP and CPP F o, significant effects on the CSID in speech contexts, and strong and significant effects on the measure of spectral tilt (L/H ratio). However, the correlations between the various headset microphones and a reference precision microphone were excellent (rs > .90). CONCLUSIONS: The headset microphones under test all showed the capability to track a wide range of diversity in the voice signal. Though the use of higher quality microphones that have demonstrated specifications is recommended for typical research and clinical purposes, low-cost electret microphones may be used to provide valid measures of voice, specifically when the same microphone and signal chain is used for the evaluation of pre- versus posttreatment change or intergroup comparisons.

Effects of Laryngeal Manual Therapy on Primary Muscle Tension Dysphonia (MTD-1): Implications for MTD-1 Type.

OBJECTIVE: The study investigated effects of laryngeal manual therapy on different types of primary muscle tension dysphonia (MTD-1). STUDY DESIGN: Interventional pre-test post-test design. METHODS: Thirty-two traditional Iranian singers (mean age of 36.75 ± 9.34 years.) diagnosed with MTD-1, 8 female and 24 male, and recruited by convenience sampling completed the study. MTD-1 was classified as Morrison and Rammage's types 1-5, based on standardized criteria (1993). Pre-post-treatment measures were based on visual ratings of the larynx, acoustic analyses, auditory-perceptual assessments of voice (Auditory-Perceptual Rating Instrument for Operatic Singing Voice: EAI Scale Form), and the Persian Singing Voice Handicap Index (P-SVHI), reported before and after 10 sessions of laryngeal manual therapy (LMT). RESULTS: The most notable finding was that the number of cases with MTD-1 types 1 and 2 actually increased after treatment, while the number of cases with MTD-1 types 3, 4 and 5 decreased. The data suggested that MTD-1 types 3, 4, and 5 tended to convert to types 1 and 2 with LMT. Acoustic analyses showed a significant decrease in F0 (males only; P = 0.011), a sharp decrease in HNR from 23.26 dB to 14.74 dB (P = 0.000), and an increase in shimmer from 4.18% to 6.90 % while no appreciable change was found in jitter (P = 0.57). Mean P-SVHI score decreased significantly from 52.03 to 41.16 (P = 0.002) and EAI score increased from 4.41 to 6.31 (P = 0.000) after treatment. CONCLUSIONS: The primary finding was that the distribution of MTD-1 type changed after treatment in many cases, converting from one to another type. Acoustic as well as glottal closure measures for several participants revealed closure insufficiency after treatment, unveiled as hyperfunction was unloaded with LMT. For those participants, complementary treatments aimed at reinforcement of laryngeal closure functions would be appropriate.

Scoping Review of Voice Therapy Adherence.

OBJECTIVES: The purpose of this scoping review was to summarize key findings in the voice therapy adherence literature for individuals with phonotraumatic lesions. The particular focus was to identify how adherence has been defined and measured (operationalization and criteria for successful adherence) and to describe variables which were found to have a positive, neutral, or negative relationship with adherence to voice therapy. METHODS: Data were identified and charted using the PRISMA-ScR protocol via searches of CINAHL, PsycINFO, Pubmed, SCOPUS, and Web of Science. RESULTS: Literature mining revealed that adherence is rarely defined but is usually operationalized. "Successful completion of therapy" was the most common operationalization. Most variables studied in this field have been found to have no relationship with adherence. An incidental finding was that, most frequently, researchers have repeatedly studied variables which have already been documented to have no relationship with adherence. CONCLUSION: Research into voice therapy adherence is still emerging, and few if any variables have been identified which are strongly associated with adherence to voice therapy for people with phonotraumatic lesions. Inspiration for future research may be drawn from other disciplines, which point to relationship variables as central to the adherence process. Examination of such variables is currently underrepresented in the voice therapy literature; we suggest this and other gaps for pursuit in future research.

Behavioral Treatment for Benign Vocal Fold Lesions in Children: A Systematic Review.

Purpose This systematic review aims to identify, classify, and evaluate existing information regarding treatment for benign vocal fold lesions in children and to identify gaps and limitations that may limit effective pediatric voice treatment. Method A literature search was performed using electronic databases (PubMed and Google Scholar) as well as reference lists from previous reviews, studies, and books. Included in the present review are studies that described behavioral treatment for children with benign vocal fold lesions presumed to be phonotraumatic (vocal fold nodules and edema). Results Twenty-one studies were eligible for inclusion in the review. Eight different research designs were used, and three intervention types were identified: direct voice intervention (voice training), indirect treatment (vocal hygiene or counseling), and comparative studies that contrasted different treatment methods. The most commonly used treatment method was eclectic direct intervention, which focused on vocal exercises or voicing patterns. Postintervention improvement was reported in all studies. In general, findings suggested an advantage of direct over indirect intervention and of longer treatment duration over short-term approaches. Conclusions The findings suggest that behavioral voice therapy may be generally effective in treating children with vocal fold nodules. Several limitations emerged in the corpus of studies reviewed including heterogeneity of research methods, missing information about outcome measures, and inappropriate statistical analyses. Thus, a need exists for further well-designed controlled studies to enhance the body of knowledge about developmental factors affecting vocal treatment outcomes, in particular, vocal fold structure as well as cognitive and linguistic development.

Cognitive Mechanisms in Pediatric Voice Therapy - An Initial Examination.

INTRODUCTION: Voice disorders are a common communication disorder in children. Behavioral voice therapy is recommended by both Otolaryngologists and Speech-Language Pathologists as a first-line approach for treatment of benign vocal fold lesions that affect children in large numbers. However, the role of cognitive mechanisms critical to voice therapy have not yet been explored. OBJECTIVE: This proof-of-concept study aims to provide preliminary data on the potential relation between cognitive abilities and behavioral results of voice therapy for children with benign phonotraumatic vocal fold lesions. METHODS: Six children (4;05 -9;02 years) diagnosed with vocal fold nodules completed a battery of cognitive tests from the NEuroPSYchological (NEPSY-II) Assessment and a standard course of "Adventures in Voice" therapy. Recordings pre and post intervention were analyzed acoustically using the Cepstral Spectral Index of Dysphonia (CSID) and perceptually using visual analog scales (VAS) for severity and resonance separately. Raw and age-corrected scaled scores from the NEPSY-II were then examined for their possible relation to voice outcomes. RESULTS: Multiple cognitive functions correlated with voice outcomes. Raw score measures for Design Fluency, Inhibition, Fingertip Tapping, and Narrative Memory correlated favorably with all voice outcome measures. Age correlated with all NEPSY-II raw scores and perceptual voice outcome measures. Scaled scores for Auditory Attention, Design Fluency, Fingertip Tapping (Dominant hand), and Narrative Memory correlated with all voice outcome measures. CONCLUSION: Results suggest that there is merit to further investigation of the relation between cognitive skills and their development and voice treatment outcomes in children with benign phonotraumatic lesions. Future studies with larger samples will build on present findings.

Buteyko Breathing Technique for Exertion-Induced Paradoxical Vocal Fold Motion (EI-PVFM).

PURPOSE: The primary purpose of the current study was to determine the usefulness of Buteyko breathing technique (BBT) in reducing dyspnea in patients with one form of Paradoxical Vocal Fold Motion (PVFM), exertion-induced PVFM (EI-PVFM), concomitant with hyperventilation. The secondary purpose was to determine whether BBT had an effect on physiological markers of hyperventilation, as speculated by BBT theory: respiratory tidal minute volume (RTMV), end-tidal carbon dioxide (ETCO2), and resting heart rate (HR). METHODS: Using a within-subjects, repeated measures group design, 12 participants with EI-PVFM and hyperventilation underwent 12 weeks of BBT, following an initial no-treatment control condition. Outcome measures of PVFM-dyspnea frequency and severity-and of hyperventilation-HR, RTMV, and ETCO2-were acquired pre- and post-treatment. RESULTS: Results showed post-treatment decreases in dyspnea severity, HR, and RTMV, as well as increases in ETCO2. Decreases in dyspnea and RTMV measures remained after correction for alpha inflation. CONCLUSIONS: Findings suggest BBT may be useful for some individuals with EI-PVFM and hyperventilation. The high prevalence of hyperventilation in EI-PVFM found in the current study warrants further investigation.

Biosimulation of inflammation and healing in surgically injured vocal folds.

OBJECTIVES: The pathogenesis of vocal fold scarring is complex and remains to be deciphered. The current study is part of research endeavors aimed at applying systems biology approaches to address the complex biological processes involved in the pathogenesis of vocal fold scarring and other lesions affecting the larynx. METHODS: We developed a computational agent-based model (ABM) to quantitatively characterize multiple cellular and molecular interactions involved in inflammation and healing in vocal fold mucosa after surgical trauma. The ABM was calibrated with empirical data on inflammatory mediators (eg, tumor necrosis factor) and extracellular matrix components (eg, hyaluronan) from published studies on surgical vocal fold injury in the rat population. RESULTS: The simulation results reproduced and predicted trajectories seen in the empirical data from the animals. Moreover, the ABM studies suggested that hyaluronan fragments might be the clinical surrogate of tissue damage, a key variable that in these simulations both is enhanced by and further induces inflammation. CONCLUSIONS: A relatively simple ABM such as the one reported in this study can provide new understanding of laryngeal wound healing and generate working hypotheses for further wet-lab studies.

Mechanical vs manual manipulation for low back pain: an observational cohort study.

OBJECTIVE: This is an observational prospective cohort study to explore the treatment effect of mechanical vs manual manipulation for acute low back pain. METHODS: Ninety-two patients with a history of acute low back pain were recruited from 3 private chiropractic offices, 2 of which used manual lumbar manipulation and 1 used mechanical instrument manipulation (Activator) as their primary modes of treatment. The chiropractors used their "treatment-as-usual" protocols for a maximum of 8 visits or 4 weeks, whichever occurred first. Primary outcome measures were changes in Numeric Pain Rating Scale (NPRS) and Oswestry Disability Index (ODI) scores from baseline to 4 weeks. The linear regression models were adjusted for baseline NPRS and ODI scores, age, and treatment expectancy. RESULTS: Comparison of baseline characteristics did not show any significant differences between the groups except for age (38.4 vs 49.7 years, P < .001) and treatment expectancy (5.7 vs 6.3, P = .003). Linear regression revealed significantly lower NPRS scores in the manual manipulation group at 4 weeks (beta = -1.2; 95% confidence interval, -2.1 to -.28) but no significant difference in ODI scores between the 2 groups at 4 weeks (beta = 1.5; 95% confidence interval, -8.3 to 2.4). Treatment expectancy, but not age, was found to have a significant main effect on both NPRS and ODI scores at 4 weeks. Exploratory analysis of the clinical patterns of care between the clinicians revealed significant differences in treatment frequency, duration, modality, and radiograph use between the 2 cohorts. CONCLUSIONS: This study highlights the challenges inherent with conducting research that allows for "treatment as usual." The data and experience derived from this investigational study will be used to design a future randomized clinical trial in which tighter controls will be imposed on the treatment protocol.

Behavioral treatment of voice disorders in teachers.

INTRODUCTION: The purpose of this paper is to review the literature on the behavioral treatment of voice disorders in teachers. The focus is on phonogenic disorders, that is voice disorders thought to be caused by voice use. METHODS: Review of the literature and commentary. RESULTS: The review exposes distinct holes in the literature on the treatment of voice problems in teachers. However, emerging trends in treatment are noted. For example, most studies identified for review implemented a multiple-therapy approach in a group setting, in contrast to only a few studies that assessed a single-therapy approach with individual patients. Although the review reveals that the evidence around behavioral treatment of voice disorders in teachers is mixed, a growing body of data provides some indicators on how effectively rehabilitation of teachers with phonogenic voice problems might be approached. Specifically, voice amplification demonstrates promise as a beneficial type of indirect therapy and vocal function exercises as well as resonant voice therapy show possible benefits as direct therapies. Finally, only a few studies identified even remotely begin to meet guidelines of the Consolidated Standards of Reporting Trials statement, a finding that emphasizes the need to increase the number of investigations that adhere to strict research standards. CONCLUSIONS: Although data on the treatment of voice problems in teachers are still limited in the literature, emerging trends are noted. The accumulation of sufficient studies will ultimately provide useful evidence about this societally important issue.

Perceptual Clinical Features in Exercise-Induced Laryngeal Obstruction (EILO): Toward Improved Diagnostic Approaches.

INTRODUCTION: Athletes with exercise-induced laryngeal obstruction (EILO) (previously commonly referred to as paradoxical vocal fold motion disorder, or paradoxical vocal fold motion, among other terms) are often misdiagnosed, resulting in prolonged, and at times inappropriate, clinical management. The high prevalence of misdiagnosis is largely due to a lack of universal consensus of key clinical features indicating EILO and a dearth of validated quantitative approaches to accurately detect episodic laryngeal breathing disorders (ELBD) from other pathologies. Additionally, mechanisms underlying EILO clinical presentation are poorly understood, further confounding identification and management of the condition. Therefore, the objectives of this study were twofold. The first was to identify patient-centered perception of symptoms that could distinguish adolescent athletes with EILO from athletes without the condition, at baseline (rest) and during an exercise challenge (provocation), and to quantify symptom severities for use as preliminary diagnostic benchmarks. The second objective was to investigate the merit of one commonly proposed mechanism in the EILO literature-stress reactivity (temperament)-by comparing personality traits in athletes with and without EILO. METHODS: Twelve (12) athletes diagnosed with EILO and 14 healthy athletic volunteers without the condition were asked to rate the severity of their present symptoms using a 0-100 continuous visual analog scale. Participants then underwent an exercise challenge with simultaneous laryngoscopy and were asked to complete the same set of symptom severity ratings experienced during rigorous exercise. Finally, participants completed the Fear subscale on the early adolescent temperament questionnaire-revised (EATQ-R) to measure self-perceived levels of stress reactivity. RESULTS: There were significant group differences for inspiratory and expiratory dyspnea with exercise (P = 0.01). Symptoms of stridor (EILO: P = .01; control: P = .001) and throat tightness (EILO: P = .01, control: P = .01) were statistically different between rest and exercise in both groups. However, no group differences were found on these two parameters (P > .05). Other symptoms from the list of previously purported symptoms indicative of ELBD (e.g. cough, dysphonia) were infrequently reported in the exercise variant. Additionally, measurements of stress reactivity on the EATQ-R Fear subscale were similar between the two athletic groups. Interestingly, EATQ-R Fear Subscale scores for both groups were significantly higher compared to typical adolescents in the U.S. population (P < .001, respectively). DISCUSSION: Results suggest dyspnea severity, particularly when experienced during an exercise-induced ELBD (EILO) episode, is the most sensitive symptom parameter to distinguish individuals with EILO from those without the condition. These findings confirm previous literature describing episodic laryngeal breathing disorders in clinical cohorts. Results also showed symptoms of throat tightness and stridor is more prevalent during exercise, compared to rest. However, the level of their severity occurred variably across both groups of athletes and may point to a less robust indication of pathology. Finally, similarities to stress reactivity between the two athletic groups imply certain temperaments historically attributed to patients with EILO may instead better reflect temperaments in competitive young athletes, in general. CONCLUSION: Study findings highlight the importance of using normative comparisons in the study of episodic laryngeal breathing disorders to prevent overgeneralization of characteristics to clinical cohorts. Results also speak of the clinical utility of exercise challenge to improve specificity of EILO diagnosis.

Metabolic Mechanisms of Vocal Fatigue.

OBJECTIVE: This study aimed to identify potential metabolic mechanisms including (1) neuromuscular inefficiency, (2) cardiovascular recovery deficits, or (3) both, in individuals with complaints of vocal fatigue. STUDY DESIGN: Within- and between-subjects group design was used in this study. METHODS: Three groups of women participated in the study, including (1) individuals with complaints of vocal fatigue; (2) vocally healthy sedentary individuals; and (3) vocally healthy, cardiovascularly conditioned individuals. Group assignment was based on results from the Vocal Fatigue Index, laryngeal examination, and self-report regarding exercise regimens. Metabolic profiles were obtained using gas exchange measures monitored during vocal task performance (reading) at two different loudness levels, and during recovery from reading. RESULTS: Statistical analyses did not reveal reliable group differences in metabolic cost for or recovery from vocal tasks. However, descriptive review of oxygen uptake and recovery kinetics revealed patterns indicating reliance on differential energy resources for the vocal task in individuals with vocal fatigue compared with cardiovascularly trained, vocally healthy individuals in particular. Slow oxygen uptake kinetics at task onset was a characteristic of the vocal fatigue group, indicating a general reliance on anaerobic resources to meet the demands of the vocal task, pointing to possible neuromuscular inefficiency. Individuals with vocal fatigue also demonstrated an increase in oxygen consumption following vocal task compared with cardiovascularly trained individuals, suggesting possible cardiovascular recovery deficits. CONCLUSION: This study provides initial data relevant to possible metabolic mechanisms of vocal fatigue and the potential relevance of aerobic conditioning in individuals with such fatigue.

Retrospective Studies: A Fresh Look.

PURPOSE: A first objective was to provide an overview of advantages and cautions around so-called retrospective clinical studies. A second objective was to provide guidelines for strong studies that can make a valid contribution to the clinical literature, whether these studies are prospective, retrospective, experimental, or observational. METHOD: Invited commentaries were solicited from statistical and study design experts. RESULTS: The strength of a clinical study does not lie so much with its point in time relative to data generation, as it lies with study design. In fact, quite surprisingly, data collected in the past can be modeled to create a prospective study, if appropriate. One distinctive strength of observational studies-which are sometimes but not always retrospective-is the ability to obtain a large corpus of data from medical databases rapidly, as sometimes warranted by pressing health care policy and practice issues. CONCLUSION: Retrospective studies, often considered inferior to prospective, randomized, and controlled clinical trials, can have strength and validity often not recognized in the hierarchy of clinical data.