Inter-device reliability of DSI measurement.

The Dysphonia Severity Index (DSI) is a measure that quantifies the overall vocal quality. The aim of the study is to evaluate the reliability of DSI measurements. The DSIs of 30 subjects were therefore measured using LingWAVES (WEVOSYS) and DiVAS (XION). To evaluate the inter-device reliability of DSI measurement, the devices' results were compared for each subject. The DSI values of both devices showed great differences. The calculated DSI differences of 95% of the subjects were within the limits of +2.39 and -2.82, which makes a clinical interpretation of severity of voice disorder using different devices questionable. The technical and procedural aspects of measurement divergences are discussed, and the need to define hardware and software standards is shown.

Biofeedback on voice use in call center agents in order to prevent occupational voice disorders.

BACKGROUND: Call center agents (CCAs) are at high risk of voice disorders because of high-demanding vocal load and work-related stress factors. Goal of this prospective study was to examine the voice use at work and to introduce biofeedback software into real-life workplace situation to improve vocal performance. Individual fundamental frequency, sound pressure level (SPL) of speaking voice, and syllables per second should be optimized by visualization on-screen. Further, its impact on vocal attrition and vocal constitution should be investigated. METHODS: Over a period of 6 months, 76 call center advisors voluntarily participated in this study (37 female, 39 male, mean age 29.3 years). At the beginning of the study, all the subjects received voice range profile (VRP) measurements and acoustic voice analyses at the beginning and at the end of shift. Additionally, several questionnaires have been completed. The subjects were classified into either the study group (group 1) or the control group (group 2). Group 1 had open access to results of the biofeedback software program at their workplace, and group 2 did not. The VRP measurements, questionnaires, and acoustic voice analyses were repeated 4 weeks later again at the beginning and at the end of shift. RESULTS: All the subjects confirmed a rather high vocal load. In contrast, almost none of the subjects received any voice training before entering the floor. The percentage of voice-related hoarseness and regular throat clearing was rather high in both groups. The statistical analyses revealed a significant improvement of vocal performance in subjects with vocal fatigue in the study group when compared with the control group after a 4-week biofeedback intervention. All the subjects with vocal hypofunction defined as maximum SPLs lower than 90 dB in VRP measurements improved to normal voice constitution at the end of the study in contrast to the control group. CONCLUSION: Biofeedback is a suitable method to improve vocal awareness and vocal performance of CCAs.

Normative voice range profiles in vocally trained and untrained children aged between 7 and 10 years.

Only limited data on normal vocal constitution and vocal capabilities in school-aged children are available. To take better care of children's voices, it might be helpful to know voice ranges and limits of not only vocally trained but also vocally untrained children. Goal of this study was the evaluation of singing voice capabilities of vocally healthy children with different social and vocal/musical backgrounds using voice range profile measurements (VRP). VRP percentiles that reflect constitutional aspects were suggested. In this cross-sectional study, 186 children (aged between seven and 10 years), attending five schools, were included. VRP measurements were performed under field conditions. Interviews and questionnaires regarding vocal strain and vocal training were applied; the answers were used for classification of singing activity and vocal training (KLASAK). All children reached a mean singing voice range of at least two octaves. By using the answers of interviews and questionnaires, the children could be classified according to vocal strain and vocal training. The groups showed no significant differences regarding VRP measurements. In the following step, percentiles were calculated. Twenty-five percent of all children (P25) reached a minimum voice range of almost two octaves, namely, 22 semitones (ST) from 220 to 784 Hz with soft and loud singing. Half of the children (P50) had a voice range of 24 ST (2 octaves), while soft singing and a larger voice range of 26 ST while loud singing. The measurements of third quartile (P75) revealed that 25% of children have even a larger voice range than 29 dB (from 196 Hz/g to 1047 Hz/c3) and can sing at most frequencies louder than 90 dB. P90 demonstrated that 10% of the children can sing even lower or higher than the frequency range between 196 Hz/g and 1319 Hz/e3 analyzed. The voice range seems not to be constrained by social but by voice/musical background: children of vocally/musically encouraged schools had wider voice ranges. This underlines the necessity of regular singing lessons already in primary schools. The percentile VRP introduced might help to evaluate the vocal constitution and vocal capabilities of a child.