The Effect of Tonal Changes on Voice Onset Time in Mandarin Esophageal Speech

SUMMARY: The present study investigated the effect of tonal changes on voice onset time (VOT) between normal laryngeal (NL) and superior esophageal (SE) speakers of Mandarin Chinese. VOT values were measured from the syllables /pha/, /tha/, and /kha/ produced at four tone levels by eight NL and seven SE speakers who were native speakers of Mandarin. Results indicated that Mandarin tones were associated with significantly different VOT values for NL speakers, in which high-falling tone was associated with significantly shorter VOT values than mid-rising tone and falling-rising tone. Regarding speaker group, SE speakers showed significantly shorter VOT values than NL speakers across all tone levels. This may be related to their use of pharyngoesophageal (PE) segment as another sound source. SE speakers appear to take a shorter time to start PE segment vibration compared to NL speakers using the vocal folds for vibration.     

Comparisons of Voice Onset Time for Trained Male Singers and Male Nonsingers During Speaking and Singing

This study was designed to examine the temporal acoustic differences between male trained singers and nonsingers during speaking and singing across voiced and voiceless English stop consonants. Recordings were made of 5 trained singers and 5 nonsingers, and acoustically analyzed for voice onset time (VOT). A mixed analysis of variance showed that the male trained singers had significantly longer mean VOT than did the nonsingers during voiceless stop production. Sung productions of voiceless stops had significantly longer mean VOTs than did the spoken productions. No significant differences were observed for the voiced stops, nor were any interactions observed. These results indicated that vocal training and phonatory task have a significant influence on VOT.     

Efficacy of a Behaviorally Based Voice Therapy Protocol for Vocal Nodules

The aim of this study was to assess the effects on vocal function of voice therapy for vocal nodules. Perceptual and physiological progressive changes were examined during a strictly structured, behaviorally based voice therapy protocol in which 11 women with vocal nodules participated. Randomized audio recordings from pretherapy and from each of the therapy approaches (vocal hygiene, respiration, direct facilitation, carryover) were used for perceptual evaluations. Six speech-language pathologists rated ten voice quality parameters. Two evaluation procedures were performed and compared. Interlistener reliability was sufficiently high in both tests. Significant effects of therapy were found for decreased overall dysphonia, press, instability, gratings, roughness, vocal fry, and "scrape." Nonsignificant group effects were found for breathiness, aphonic instances, and lack of sonority. No significant parameter changes occurred between baseline assessment and the completion of the initial (vocal hygiene) phase of therapy. Significant changes were found following the direct facilitation and respiration phases of therapy. Videostroboscopic evaluations made by two laryngologists showed that in no case were the nodules completely resolved. However, the nodules had decreased in size and edema was reduced after therapy for all clients, but one. Combined results suggest: (1) Alterations in vocal function were reflected in perceptual parameters, and (2) the voice therapy had a positive effect on voice quality, vocal status, and vocal function for the majority of the vocal nodule clients.     

Vocal Problems Among Teachers: Evaluation of a Preventive Voice Program

Vocal education programs for teachers may prevent the emergence of vocal disorders; however, only a few studies have tried to evaluate the effectiveness of these preventive programs, particularly in the long term. Two hundred and sixty-four subjects, mostly kindergarten and primary school female teachers, participated in a course on voice care, including a theoretical seminar (120 minutes) and a short voice group therapy (180 minutes, small groups of 20 subjects). For 3 months, they had to either attend the vocal ergonomics norms and, as psychological reinforcement, they had to make out a daily report of vocal abuse, or to follow the given exercises for a more efficient vocal technique, reporting on whether the time scheduled was respected or not. The effectiveness of the course was assessed in a group of 21 female teachers through a randomized controlled study. Evaluation comprehended stroboscopy, perceptual and electro-acoustical voice analysis, Voice Handicap Index, and a course benefit questionnaire. A group of 20 teachers matched for age, working years, hoarseness grade, and vocal demand served as a control group. At 3 months evaluation, participants demonstrated amelioration in the global dysphonia rates (P=0.0003), jitter (P=0.0001), shimmer (P=0.0001), MPT (P=0.0001), and VHI (P=0.0001). Twelve months after the course, the positive effects remained, although they were slightly reduced. In conclusion, a course inclusive of two lectures, a short group voice therapy, home-controlled voice exercises, and hygiene, represents a feasible and cost-effective primary prevention of voice disorders in a homogeneous and well-motivated population of teachers.     

Predicted Singers' Vocal Fold Lengths and Voice Classification—A Study of X-Ray Morphological Measures

Students admitted to the solo singing education at the University of Music Dresden, Germany have been submitted to a detailed physical examination of a variety of factors with relevance to voice function since 1959. In the years 1959–1991, this scheme of examinations included X-ray profiles of the singers' vocal tracts. This material of 132 X-rays of voice professionals was used to investigate different laryngeal morphological measures and their relation to vocal fold length. Further, the study aimed to investigate if there are consistent anatomical differences between singers of different voice classifications. The study design used was a retrospective analysis. Vocal fold length could be measured in 29 of these singer subjects directly. These data showed a strong correlation with the anterior-posterior diameter of the subglottis and the trachea as well as with the distance from the anterior contour of the thyroid cartilage to the anterior contour of the spine. These relations were used in an attempt to predict the 132 singers' vocal fold lengths. The results revealed a clear covariation between predicted vocal fold length and voice classification. Anterior-posterior subglottic-tracheal diameter yielded mean vocal fold lengths of 14.9, 16.0, 16.6, 18.4, 19.5, and 20.9 mm for sopranos, mezzo-sopranos, altos, tenors, baritones, and basses, respectively. The data support the assumption that there are consistent anatomical laryngeal differences between singers of different voice classifications, which are of relevance to pitch range and timbre of the voice.