Abstract The aim of this study was twofold: to develop a method for collecting voice data from natural working environments; and to study loading changes. Changes caused by loading were approached from two perspectives: the relationship between subjective complaints and objectively measured voice features, and the changes of objective variables during one working day. Subjects consisted of female teachers from primary and secondary schools. Six separate studies were carried out, the number of subjects for each one ranging from 3 to 33. The subjects were 33 - 59 years old. Recordings were made of their voices both during breaks and lessons with a portable DAT recorder. The recordings made during the breaks were collected on three days of one week, and four times on each week. The speech samples of the lessons were taken from the first and last lesson of the day. Subjects filled in a questionnaire about their voice, which divided them into two groups: those with few complaints (the FC group) and those with many complaints (the MC group). In addition, three subjects performed a laboratory voice loading task. The speech sample recorded during breaks was a maximally sustained [a], from which fundamental frequency (F0), jitter and shimmer were analyzed. The lesson samples were analyzed for F0, its standard deviation (F0 SD), sound pressure level (SPL), its standard deviation (SPL SD), F0 time ( = active vibration time of the vocal folds) and long-time average spectrum (LTAS). The laboratory samples (a simple reading task) were measured for F0. Additionally, an index (F0 x F0 time/ 1000) for assessing voice loading is presented. The results showed that voice complaints correlated with objectively measured voice features: the more the complaints, the higher the F0 and SPL, the larger the F0 SD and the steeper the tilt of the LTAS, the latter indicating that the voices of the MC group had a tendency towards a hypofunctional voice usage. In addition, at the end of the working week the shimmer values of the MC group were lower than those of the FC group. During the working day, the F0 rose, F0 SD and SPL SD increased and the LTAS levelled out (changes towards a hyperfunctional voice usage). Some of these changes are caused by the classroom situation, some by the teachers themselves, and some (obviously the changes of the F0 and the LTAS) by physiological alterations. Interestingly, the main changes, which were the F0 rise and levelling of the spectrum, occurred in the FC-group. The changes possibly reflect a normal adaptation of the human body, and they may act as an alarm system for avoiding excessive strain and exhaustion. The voice loading index correlated with the voice complaints. The experiment showed that the used method is well suited for the measurement of voices in working places. The maximally sustained phonation proved to be a suitable voice task for the measurement of the voice in working places where subjects have to do a task independently. The results also showed that F0 yields different values in different conditions and with different voice tasks. This deserves attention when defining standards for acoustic variables.

Professional voice users such as singers and teachers are at high risk for vocal injury. A literature review was conducted to understand the prevalence of voice problems and the effectiveness of vocal hygiene education. The findings of the review suggested that in order to reduce the impact of voice disorders, it is imperative that the education of singers and teachers include how the voice functions and how to best take care of it. The purpose of this study was to discover what students on a collegiate level know about vocal anatomy, physiology, and vocal hygiene issues. It was hypothesized that graduate students who had taken a pedagogy course, were more knowledgeable about vocal anatomy, physiology, and vocal health than undergraduate or graduate students who had not had such a course. A survey was administered to voice students at a large university music program to ascertain the level of student knowledge. An analysis of the survey results provides educators with insight into specific areas of student deficiency and current collegiate pedagogical needs. The findings from the study survey were applied to recommendations for undergraduate and graduate vocal pedagogy curriculum, with an emphasis on anatomy, physiology, and preventative care of the voice. Course descriptions, objectives, and assessment methods were included for each vocal pedagogy course. The study recommended that all voice students receive information that allows them to make educated decisions regarding voice care and prepares them to be leaders in teaching singing based on voice science. In addition to anatomy and physiology of the voice, vocal hygiene is an important topic to be included in pedagogy curriculum. Issues and resent research in vocal hygiene were discussed including: speaking habits, hydration, reflux, medical management, etc. and how these contribute to or detract from efficient voice use.

Teachers frequently present with voice problems as result of functional voice hyperfunction and it seems that occupational duties often impede successful implementation of a conventional voice conservation strategies. The goal of this single-subject study was to investigate the practical value of personal voice amplification as an assistive option for teachers experiencing occupation-related voice problems The physical state of a teacher’s vocal chords and specific perceptual and acoustic attributes of her voice were evaluated before and after a period of conventional voice conservation, and also before and after a period during which personal voice amplification was used as an augmentative strategy. In the course of the study it was in the interest of the subject that a persistent vocal fold nodule be removed surgically. The research design was adapted accordingly and the study consequently included a pre- and post surgical phase. Physical examinations of the vocal cords reflected the positive effect of the surgical removal of a vocal fold nodule. An improvement in the general status of the vocal cords was also noted following periods during which personal voice amplification was used in combination with a conventional voice conservation strategy. Perceptual and acoustic analysis of voice quality confirmed the positive effect of the surgical intervention. Although a panel of judges did not detect an improvement in the subject’s voice quality following the assistive use of the personal amplifier, several acoustic voice parameters showed improvement or normalised after the use of personal voice amplification in combination with conventional voice conservation strategies. The subject’s repeated evaluation of her own voice experiences, as well as her view of the practicability of the two voice conservation strategies, revealed a remarkably positive attitude towards the augmentative use of personal voice amplification. The conclusion is that teachers who experience occupational voice problems could benefit from the use of personal voice amplification in combination with a conventional voice conservation strategy. / Dissertation (M (Communication Pathology))--University of Pretoria, 2006. / Speech-Language Pathology and Audiology / Unrestricted