A feasibility study on non-invasive oxidative metabolism detection and acoustic assessment of human vocal cords by using optical technique.

Voice disorder such as vocal fatigue is a common and complex multifaceted clinical problem that presents a significant impact on quality of life. In this study, the functional near-infrared diffuse optical technique (fNIRS-DOT) was proposed as a novel approach for human vocal cords oxidative metabolism detection and acoustic assessment simultaneously to provide a multidimensional assessment of voice disorder. A totally of 60 healthy subjects included 30 male and 30 female adults of age-matched were recruited and performed a vocal loading task to trigger a mild inflammation of the vocal cords in this study. In the results of oxidative metabolism, the vocal cords expressed hypoxia after vocal loading task in both male and female groups that could provide relevant information on the relationship between tissue oxygen consumption and supply for vocal cords diagnosis. Additionally, the results of optical acoustic assessment revealed the worse/changes voice quality after vocal loading task. Therefore, integration of non-invasive oxidative metabolism detection and acoustic assessment by using optical technique could provide more relevant information for diagnosis of voice disorders. The multi-functional vocal cords detection system could provide a good feasibility for clinical applications such as diagnosis and therapeutic monitoring of voice disorder.

Investigating the Role of Salivary Cortisol on Vocal Symptoms.

Purpose: We investigated whether participants who reported more often occurring vocal symptoms showed higher salivary cortisol levels and if such possible associations were different for men and women. Method: The participants (N = 170; men n = 49, women n = 121) consisted of a population-based sample of Finnish twins born between 1961 and 1989. The participants submitted saliva samples for hormone analysis and completed a web questionnaire including questions regarding the occurrence of 6 vocal symptoms during the past 12 months. The data were analyzed using the generalized estimated equations method. Results: A composite variable of the vocal symptoms showed a significant positive association with salivary cortisol levels (p < .001). Three of the 6 vocal symptoms were significantly associated with the level of cortisol when analyzed separately (p values less than .05). The results showed no gender difference regarding the effect of salivary cortisol on vocal symptoms. Conclusions: There was a positive association between the occurrence of vocal symptoms and salivary cortisol levels. Participants with higher cortisol levels reported more often occurring vocal symptoms. This could have a connection to the influence of stress on vocal symptoms because stress is a known risk factor of vocal symptoms and salivary cortisol can be seen as a biomarker for stress.

Associations Between Vocal Symptoms and Genetic Variants in the Oxytocin Receptor and Arginine Vasopressin 1A Receptor Gene.

Purpose: Oxytocin and arginine vasopressin are associated with different aspects of the stress response. As stress is regarded as a risk factor for vocal symptoms, we wanted to explore the association between the oxytocin receptor gene (OXTR) and arginine vasopressin 1A receptor gene (AVPR1A) single-nucleotide polymorphisms (SNPs) and vocal symptoms. We also wanted to explore whether such effects might be mediated by cortisol because oxytocin and vasopressin are associated with cortisol levels. Method: A population-based sample (N = 657) of Finnish twins (born 1961-1989) completed a web questionnaire on the occurrence of vocal symptoms. A total of 170 participants submitted saliva samples for hormone analysis. A total of 20 OXTR and AVPR1A SNPs were analyzed. Results: Three OXTR polymorphisms (rs2270465, rs2268493, rs7632287) and 2 AVPR1A polymorphisms (rs1587097, rs1042615) showed nominal effects (p < .05) on vocal symptoms, of which 1 (rs1587097) remained significant after correcting for multiple testing (p = .003). We found potential mediation of the effect of the OXTR rs2268493 polymorphism on vocal symptoms through levels of cortisol. Conclusions: The associations between variants of OXTR and AVPR1A and vocal symptoms indicate that oxytocin and vasopressin might influence vocal symptoms. The effect of oxytocin seems to be partly mediated through cortisol actions.

Insights Into the Role of Collagen in Vocal Fold Health and Disease.

As one of the key fibrous proteins in the extracellular matrix, collagen plays a significant role in the structural and biomechanical characteristics of the vocal fold. Anchored fibrils of collagen create secure structural regions within the vocal folds and are strong enough to sustain vibratory impact and stretch during phonation. This contributes tensile strength, density, and organization to the vocal folds and influences health and pathogenesis. This review offers a comprehensive summary for a current understanding of collagen within normal vocal fold tissues throughout the life span as well as vocal pathology and wound repair. Further, collagen's molecular structure and biosynthesis are discussed. Finally, collagen alterations in tissue injury and repair and the incorporation of collagen-based biomaterials as a method of treating voice disorders are reviewed.

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.

Protective Effect of Astaxanthin on Vocal Fold Injury and Inflammation Due to Vocal Loading: A Clinical Trial.

OBJECTIVES: Professional voice users, such as singers and teachers, are at greater risk of developing vocal fold injury from excessive use of voice; thus, protection of the vocal fold is essential. One of the most important factors that aggravates injury is the production of reactive oxygen species at the wound site. The purpose of the current study was to assess the effect of astaxanthin, a strong antioxidant, on the protection of the vocal fold from injury and inflammation due to vocal loading. STUDY DESIGN: This study is an institutional review board-approved human clinical trial. METHODS: Ten male subjects underwent a 60-minute vocal loading session and received vocal assessments prior to, immediately after, and 30 minutes postvocal loading (AST(-) status). All subjects were then prescribed 24 mg/day of astaxanthin for 28 days, after which they received the same vocal task and assessments (AST(+) status). Phonatory parameters were compared between both groups. RESULTS: Aerodynamic assessment, acoustic analysis, and GRBAS scale (grade, roughness, breathiness, asthenia, and strain) were significantly worse in the AST(-) status immediately after vocal loading, but improved by 30 minutes after loading. In contrast, none of the phonatory parameters in the AST(+) status were statistically worse, even when measured immediately after vocal loading. No allergic responses or adverse effects were observed after administration of astaxanthin. CONCLUSIONS: The current results suggest that astaxanthin can protect the vocal fold from injury and inflammation caused by vocal loading possibly through the regulation of oxidative stress.

Verbal forward digit span in Spanish population / Amplitud verbal de dígitos en orden directo en población española

BACKGROUND: Older people complain of difficulties in recalling telephone numbers and being able to dial them in the correct order. This study examined the developmental trend of verbal forward digit span across adulthood and aging in a Spanish population, as an index of one of the components of Baddeley's working memory model- the phonological loop-, which illustrates these two aspects. METHOD: A verbal digit span was administered to an incidental sample of 987 participants ranging from 35 to 90 years old. The maximum length was defined that participants could recall of at least two out of three series in the same order as presented with no errors. Demographic variables of gender and educational level were also examined. RESULTS: The ANOVA showed that the three main factors (age group, gender and educational level) were significant, but none of the interactions was. Verbal forward digit span decreases during the lifespan, but gender and educational level affect it slightly. CONCLUSION: Phonological loop is affected by age. The verbal forward digit span in this study is generally lower than the one reported in other studies

ANTECEDENTES: Las personas mayores se quejan con frecuencia de las dificultades que tienen para recordar números de teléfono o para marcarlos en el orden correcto. Este estudio investiga el desarrollo de la amplitud verbal de dígitos en orden directo en adultos y personas mayores en población española, como índice de uno de los componentes del modelo de memoria operativa de Baddeley: el lazo fonológico, que precisamente ilustra estos dos aspectos. MÉTODO: la tarea verbal de amplitud de dígitos en orden directo se administró a una muestra incidental de 987 participantes, entre 35 y 90 años. Se definió como la longitud mayor de series de dígitos repetidas correctamente en, al menos, dos de las tres series. Variables demográficas, género y nivel educativo también se examinaron. RESULTADOS: el ANOVA mostró que los tres factores principales (grupo de edad, género y nivel educativo) fueron significativos, pero ninguna de las interacciones alcanzó la significación. La amplitud verbal de dígitos en orden directo desciende durante el ciclo vital, pero tanto género como nivel educativo afectaron ligeramente. CONCLUSIONES: el lazo fonológico está afectado por la edad. La amplitud verbal de dígitos en orden directo fue, en general, menor que la encontrada en otros estudios

Acoustic parameters and salivary IL-6 levels in overweight and obese teachers.

OBJECTIVE: Either obesity or vocal loading task leads to elevation of proinflammatory cytokines such as interleukin 6 (IL-6). However, it is unknown whether vocal parameters after vocal loading are correlated with body mass index (BMI) or IL-6. We hypothesize that vocal loading induces an elevation of acoustic parameters of voice and salivary IL-6 in overweight and obese people. METHODS: A total of 33 schoolteachers without any self-reported voice alterations were invited to participate in this study. Participants were classified according to BMI into normal, overweight, and obese groups. The vocal loading task consisted of loud speech (60-90 minutes) in their classroom. Salivary and voice samples were taken before and after vocal loading. Perceptual and self-reported voice alterations and objective voice analyses were investigated. The relative concentration of salivary IL-6 was estimated by a colorimetric assay. RESULTS: Obese teachers showed a significant elevation in fundamental frequency value after vocal loading. In addition, reduction in harmonics-to-noise ratio (HNR) was observed in teachers with normal weight after vocal loading but not in overweight or obese groups. No significant correlation was observed between BMI and any of the acoustic parameters analyzed or salivary IL-6 levels. Furthermore, teachers who were overweight showed a significant increase in the salivary IL-6 levels after vocal loading. Interestingly, salivary IL-6 levels were positively correlated with HNR value in the overweight group after vocal loading. CONCLUSION: Excessive body weight is related to alterations in fundamental frequency and HNR. In addition, HNR, but not BMI, is associated with salivary IL-6 levels in overweight teachers.

Insights into the role of elastin in vocal fold health and disease.

Elastic fibers are large, complex, and surprisingly poorly understood extracellular matrix macromolecules. The elastin fiber, generated from a single human gene--elastin, is a self assembling integral protein that endows critical mechanical proprieties to elastic tissues and organs such as the skin, lungs, and arteries. The biology of elastic fibers is complex because they have multiple components, a tightly regulated developmental deposition, a multistep hierarchical assembly, and unique biomechanical functions. Elastin is present in vocal folds, where it plays a pivotal role in the quality of phonation. This review article provides an overview of the genesis of elastin and its wide-ranging structure and function. Specific distribution within the vocal fold lamina propria across the lifespan in normal and pathological states and its contribution to vocal fold biomechanics will be examined. Elastin and elastin-derived molecules are increasingly investigated for their application in tissue engineering. The properties of various elastin-based materials will be discussed and their current and future applications evaluated. A new level of understanding of the biomechanical properties of vocal fold elastin composites and their molecular basis should lead to new strategies for elastic fiber repair and regeneration in aging and disease.

Vibration stimulates vocal mucosa-like matrix expression by hydrogel-encapsulated fibroblasts.

The composition and organization of the vocal fold extracellular matrix (ECM) provide the viscoelastic mechanical properties that are required to sustain high-frequency vibration during voice production. Although vocal injury and pathology are known to produce alterations in matrix physiology, the mechanisms responsible for the development and maintenance of vocal fold ECM are poorly understood. The objective of this study was to investigate the effect of physiologically relevant vibratory stimulation on ECM gene expression and synthesis by fibroblasts encapsulated within hyaluronic acid hydrogels that approximate the viscoelastic properties of vocal mucosa. Relative to static controls, samples exposed to vibration exhibited significant increases in mRNA expression levels of HA synthase 2, decorin, fibromodulin and MMP-1, while collagen and elastin expression were relatively unchanged. Expression levels exhibited a temporal response, with maximum increases observed after 3 and 5 days of vibratory stimulation and significant downregulation observed at 10 days. Quantitative assays of matrix accumulation confirmed significant increases in sulphated glycosaminoglycans and significant decreases in collagen after 5 and 10 days of vibratory culture, relative to static controls. Cellular remodelling and hydrogel viscosity were affected by vibratory stimulation and were influenced by varying the encapsulated cell density. These results indicate that vibration is a critical epigenetic factor regulating vocal fold ECM and suggest that rapid restoration of the phonatory microenvironment may provide a basis for reducing vocal scarring, restoring native matrix composition and improving vocal quality.

Vocal fold nodules: morphological and immunohistochemical investigations.

The objective of this study was to investigate the morphological and immunohistochemical characteristics of vocal fold nodules. The study design was prospective and retrospective. For the histological study, we reviewed 15 slides from the surgical cases of vocal fold nodules, in which we analyzed epithelium, basal membrane (bm), and lamina propria. For the transmission and scanning electron microscopy (TEM, SEM) studies, five new cases on vocal fold nodules were included. Immunohistochemistry study was carried out in the 15 specimens, using antifibronectin, antilaminin, and anticollagen IV antibodies. The main histological alterations were epithelial hyperplasia (73.33%), basement membrane thickening (86.66%), edema, and fibrosis (93.33%). SEM--reduction in mucous lacing and increase in the desquamating cells, without epithelial erosion. TEM--hyperplasia of the epithelium, enlargement of the intercellular junctions, which was filled by fluid, subepithelial thickening of the lamina reticularis, and break points in the basal membrane. Immunohistochemistry--we identified greater immunoexpression of fibronectin on the basal membrane, on the lamina propria, and around the vessels. Antilaminin and anticollagen IV antibodies showed higher pigmentation on the endothelium of the vessels than that on the basal membrane. In vocal fold nodules, combined assessment using light microscopy, electron microscopy, and immunohistochemistry can reveal important morphological details useful in characterizing these lesions.

Airway glutathione homeostasis is altered in children with severe asthma: evidence for oxidant stress.

BACKGROUND: Severe asthma is characterized by persistent airway inflammation and increased formation of reactive oxygen species. OBJECTIVES: Glutathione (GSH) is an important antioxidant in the epithelial lining fluid (ELF). We hypothesized that airway GSH homeostasis was altered in children with severe asthma and was characterized by decreased GSH and increased glutathione disulfide (GSSG) concentrations. METHODS: Bronchoalveolar lavage was obtained from 65 children with severe asthma, including 35 children with baseline airway obstruction evidenced by FEV(1) <80%. Control data were obtained from 6 children with psychogenic (habit) cough or vocal cord dysfunction undergoing diagnostic bronchoscopy and 35 healthy adult controls. GSH, GSSG, and other determinants of airway oxidative stress including glutathione S-transferase (GST), glutathione reductase (GR), glutathione peroxidase (GPx), malondialdehyde, 8-isoprostane, and H(2)O(2) were measured in the ELF. The ELF redox potential was calculated from GSH and GSSG by using the Nernst equation. RESULTS: Compared with controls, subjects with severe asthma had lower airway GSH with increased GSSG despite no differences in GST, GR, and GPx activities between groups. This was accompanied by increased malondialdehyde, 8-isoprostane, and H(2)O(2) concentrations in the ELF. GSH oxidation was most apparent in subjects with severe asthma with airway obstruction and was supported by an upward shift in the ELF GSH redox potential. CONCLUSION: Children with severe asthma have increased biomarkers of oxidant stress in the ELF that are associated with increased formation of GSSG and a shift in the GSH redox potential toward the more oxidized state.

Focal white matter changes in spasmodic dysphonia: a combined diffusion tensor imaging and neuropathological study.

Spasmodic dysphonia is a neurological disorder characterized by involuntary spasms in the laryngeal muscles during speech production. Although the clinical symptoms are well characterized, the pathophysiology of this voice disorder is unknown. We describe here, for the first time to our knowledge, disorder-specific brain abnormalities in these patients as determined by a combined approach of diffusion tensor imaging (DTI) and postmortem histopathology. We used DTI to identify brain changes and to target those brain regions for neuropathological examination. DTI showed right-sided decrease of fractional anisotropy in the genu of the internal capsule and bilateral increase of overall water diffusivity in the white matter along the corticobulbar/corticospinal tract in 20 spasmodic dysphonia patients compared to 20 healthy subjects. In addition, water diffusivity was bilaterally increased in the lentiform nucleus, ventral thalamus and cerebellar white and grey matter in the patients. These brain changes were substantiated with focal histopathological abnormalities presented as a loss of axonal density and myelin content in the right genu of the internal capsule and clusters of mineral depositions, containing calcium, phosphorus and iron, in the parenchyma and vessel walls of the posterior limb of the internal capsule, putamen, globus pallidus and cerebellum in the postmortem brain tissue from one patient compared to three controls. The specificity of these brain abnormalities is confirmed by their localization, limited only to the corticobulbar/corticospinal tract and its main input/output structures. We also found positive correlation between the diffusivity changes and clinical symptoms of spasmodic dysphonia (r = 0.509, P = 0.037). These brain abnormalities may alter the central control of voluntary voice production and, therefore, may underlie the pathophysiology of this disorder.

Towards the expression of sex hormone receptors in the human vocal fold.

BACKGROUND: The human larynx is assumed to be a steroid receptor target organ. There are only very limited data on the evidence of steroid receptors in the vocal folds, although voice alterations due to hormonal influence and treatment have been found. GOAL OF THE STUDY: To investigate the expression of estrogen alpha, progesterone, and androgen receptors in human vocal folds (vocalis muscle, glands, lamina propria, epithelium). METHODS: Immunohistochemically, vocal fold cadaver specimens of 15 autopsied patients (6 women, 9 men), which were taken approximately 4 to 8 hours postmortem were investigated. Furthermore, one (male) vocal fold biopsy obtained intraoperatively during a laryngectomy was tested. RESULTS: No specific immunohistochemical staining for the different types of steroid hormones investigated could be observed in either the postmortem taken biopsies nor the intraoperatively one. However, several unspecific staining patterns could be observed. CONCLUSION: The results of this study contradict recently published data and question the expression of sex hormone receptors in the vocal folds. Main causes of false interpretations of unspecific staining are discussed.

Three-dimensional reconstruction of immunolabeled neuromuscular junctions in the human thyroarytenoid muscle.

OBJECTIVES/HYPOTHESIS: The objective was to reveal the location of the neuromuscular junctions in a three-dimensional reconstruction of the human thyroarytenoid muscle within the true vocal fold. STUDY DESIGN: Immunohistochemical analysis of serially sectioned human true vocal folds was performed, followed by reconstruction in three dimensions using computer imaging software. METHODS: Six fresh human larynges from autopsy were harvested, fixed in formalin, and embedded in paraffin. Eight vocal cords were studied from these six larynges. Five-micron serial sections were collected throughout the entire vocal cord in an axial plane at 500-microm intervals. Immunohistochemical analysis was performed with anti-synaptophysin antibody. A computer-controlled imaging and reconstruction system was used to create a three-dimensional reconstruction from the serial sections and to represent the location of the clustered band of neuromuscular junctions within each true vocal fold. The vocal cord was divided into equal thirds from anterior to posterior for statistical analysis. RESULTS: The most neuromuscular junctions (74%) were located in the middle third, and the least (7%) were found in the anterior third. The difference in anterior-to-posterior distribution was statistically significant in all eight specimens by chi2 analysis (P <.001). CONCLUSION: The distribution of neuromuscular junctions is not random within the human thyroarytenoid muscle. Because neuromuscular junctions are most highly concentrated in a band within the mid belly of the muscle, botulinum toxin type A (Botox) injection in patients with spasmodic dysphonia should be targeted to this region.

Effects of age, sex, and disorder on voice range profile characteristics of 230 children.

In this study, the effect of age, sex, and disorder on the vocal performance of 230 children 6 to 11 years of age was investigated by means of the voice range profile (VRP). Ninety-four control children and 136 children with disorders were studied. The VRPs were quantitatively described by frequency and intensity characteristics, as well as by morphological characteristics. Significant differences between healthy children and children with disorders were found. Age has a different effect in girls than in boys regarding vocal performance. Most of the characteristics for the healthy girls change gradually over the period from 6 to 11 years. For the healthy boys, however, two age groups can be identified: one below and one above 8 years of age. It is hypothesized that the androgen dehydroepiandrosterone (DHEA) and its sulfate may play a role in this phenomenon.

Spasmodic dysphonia in a patient with the A to G transition at nucleotide 8344 in mitochondrial DNA.

Dystonia has been described in various diseases affecting mitochondrial function but spasmodic dysphonia, a form of focal dystonia, has not. We present a patient with action myoclonus affecting the hands and arms who carried the most common mutation in mitochondrial DNA causing the myoclonic epilepsy and ragged red fibers (MERRF) syndrome (the A-->G substitution at nucleotide 8344 in the tRNA(Lys) gene). This patient also had spasmodic dysphonia that was responsive to treatment with intralaryngeal botulinum toxin.

[Vocal tract disorders in women with hormonal gynecological diseases]. / Narusheniia golosovogo apparata pri disgormonal'nykh ginekologicheskikh zabolevaniiakh.

The paper analyzes the incidence rates and specific features of vocal apparatus disorders in dyshormonal gynecological diseases in the reproductive and menopausal periods. It presents a complex procedure for diagnosis and treatment, which includes the management of the patient by a phoniatrist jointly with an endocrinological gynecologist, a psychoneurologist, and a phonopedist. Drugs for correcting sexual hormone levels, psychoemotional status, venous tone, breathing exercises and phonopedic classes by using biological feedback, and physiotherapeutical methods of treatment have been used. Indications and contraindications for the use of hormonal drugs in the treatment of dyshormonal gynecological diseases in individuals of voice-and-speech professions are considered.