Current and Emerging Concepts in Muscle Tension Dysphonia: A 30-Month Review

The modern theory of hoarseness is that there are multifactorial etiologies contributing to the voice problem. The hypothesis of this study is that muscle tension dysphonia is multifactorial with various contributing etiologies. METHODS: This project is a retrospective chart review of all patients seen in the Voice Speech and Language Service and Swallowing Center at our institution with a diagnosis of muscle tension (functional hypertensive) dysphonia over a 30-month period. A literature search and review is also performed regarding current and emerging concepts of muscle tension dysphonia. RESULTS: One hundred fifty subjects were identified (60% female, 40% male, with a mean age of 42.3 years). Significant factors in patient history believed to contribute to abnormal voice production were gastroesophageal reflux in 49%, high stress levels in 18%, excessive amounts of voice use in 63%, and excessive loudness demands on voice use in 23%. Otolaryngologic evaluation was performed in 82% of patients, in whom lesions, significant vocal fold edema, or paralysis/paresis was identified in 52.3%. Speech pathology assessment revealed poor breath support, inappropriately low pitch, and visible cervical neck tension in the majority of patients. Inappropriate intensity was observed in 23.3% of patients. This set of multiple contributing factors is discussed in the context of current and emerging understanding of muscle tension dysphonia. CONCLUSIONS: Results confirm multifactorial etiologies contributing to hoarseness in the patients identified with muscle tension dysphonia. An interdisciplinary approach to treating all contributing factors portends the best prognosis.     

A Novel Laryngeal Palpatory Scale (LPS) in Patients with Muscle Tension Dysphonia

ObjectivesLaryngeal palpation is a routine clinical method for evaluation of patients with muscle tension dysphonia (MTD). The aim of this study was to develop a new comprehensive valid and reliable “laryngeal palpatory scale” (LPS), based on psychometric criteria.MethodsThe scale items were selected based on an in-depth analysis of the literature and an expert focus group. Scale item generation and item reduction were followed by a psychometric assessment. Qualitative and quantitative content validity (the content validity ratio (CVR), content validity index (CVI)), the qualitative face validity, and the inter-rater reliability were determined. For this purpose, 531 patients were assessed and finally 55 patients with primary MTD (26 women, mean age: 40.8 years, SD: 12.5; 29 male, mean age: 41.6 years, SD: 11.8) participated in the study. A weighted kappa (k*) statistic was used to examine the inter-rater reliability for each single item.ResultsBased on the CVR, three items were omitted because they had a score of less than 0.62. The CVI for all remaining items was greater than 0.79 and the scale CVI was equal to 0.96. The final 45 items were a result of the study. The inter-rater reliability for each single item ranged from 0.41 to 1, indicating moderate to almost perfect agreement.ConclusionsThe LPS is a reliable and valid instrument for assessing patients with MTD. However, future studies are needed to provide adequate data on sensitivity, specificity, concurrent validity, and cutoff scores.     

Effects of Muscle Tension Dysphonia on Tone Phonation: Acoustic and Perceptual Studies in Vietnamese Female Teachers

Muscle tension dysphonia (MTD) is a hyperfunctional voice disorder commonly seen in professional voice users. To date, published acoustic studies of this disorder have mainly focused on nontonal language speakers, and no publication has documented its impact on lexical tone characteristics. In this study, we examined whether and how this voice disorder affected acoustically and perceptually the characteristics of tones in Vietnamese teachers. Voice data were obtained from 42 Vietnamese female primary school teachers diagnosed with MTD and 30 vocally healthy teachers. Tonal data were analyzed using Computerized Speech Lab (CSL-4300B) and Speech Analyzer. Parameters analyzed included the two most important acoustic cues in Vietnamese tones, that is, tonal fundamental frequency (F₀) and laryngealization. Tonal F₀ was assessed using a factorial analysis of variance with group and career durations as independent variables. Tonal samples were also perceptually assessed by a panel of native speakers of the same dialect. The results showed that MTD lowered tonal F₀ in high tones and tones with extensive fundamental frequency variation. There was also a significant main effect for career duration; in MTD group, tonal F₀ was lower in teachers with longer career duration. The teachers with MTD showed different patterns of laryngealization compared with the control group. Tone perception was poorer for tones with extensive fundamental frequency variation and without a typical phonation type. The results in this group of teachers supported our hypothesis that MTD impairs lexical tone phonation.