Analysis of vocal abuse: fluctuations in phonation time and intensity in 4 groups of speakers

Condições de produção vocal de professores de deficientes auditivos

OBJETIVO: conhecer as condições de produção vocal de professores de alunos surdos, das seis Escolas Municipais de Ensino Especial de São Paulo. MÉTODOS: oitenta professores responderam o questionário proposto por Ferreira et al. (2003). Os dados do grupo que se auto-definiu como tendo, no passado ou no presente, alteração vocal foram cruzados com os do grupo que não fez tal referência (Teste de Correlação de Sperman). RESULTADOS: a população estudada na sua totalidade do gênero feminino e com nível superior completo, com média de idade de 37 anos, considera, na sua maioria, o ambiente de trabalho moderado; está satisfeita com o próprio desempenho na escola; e refere autonomia no planejamento das aulas. Quanto à questão da violência nas escolas, aparece com mais freqüência indisciplina em sala de aula, brigas e problemas com drogas Quanto aos riscos ambientais, mais da metade considera a acústica satisfatória, embora alguns considerem o local ruidoso e com poeira. Quanto aos aspectos gerais de saúde, os professores fazem referência em maior número à dor de cabeça e ansiedade. A maior parte das professoras não fuma, nem consome bebidas alcoólicas e (24) 30% relataram que tem ou tiveram alteração na voz. A maioria percebeu a alteração na voz há menos de dois anos e de forma insidiosa, atribuindo sua causa ao uso intensivo da voz ou pela presença de alergia. CONCLUSÃO: as condições de produção vocal das professoras pesquisadas são semelhantes às encontradas entre professores de alunos ouvintes, porém, apenas 30% fizeram referência à alteração de voz.

Ambulatory monitoring of disordered voices

OBJECTIVES

Recently developed systems for ambulatory monitoring of voice use employ miniature accelerometers placed at the base of the anterior neck to sense phonation. As it is hoped that such systems will help improve the clinical assessment and management of voice disorders, this study was undertaken to determine the impact of dysphonia severity on the accuracy of accelerometer-based estimates of vocal function.

METHODS

Simultaneous recordings were made of oral acoustic (microphone) and neck skin acceleration signals for 6 normal speakers and 18 patients with voice disorders (mild to severe dysphonia) as they performed several speech tasks. Measures of phonation time, fundamental frequency, and sound pressure level were extracted from the two types of signals and compared.

RESULTS

It was generally demonstrated that accelerometer-based measures closely approximated corresponding measurements obtained from a microphone signal across all levels of dysphonia severity. Furthermore, there was evidence that in some cases the accelerometer may actually represent a more robust approach for estimating phonation parameters in disordered voices.

CONCLUSIONS

The results generally support the recent application of accelerometers as phonation sensors in ambulatory voice monitoring systems that can be used in the clinical assessment and management of voice disorders.

Voicing and silence periods in daily and weekly vocalizations of teachers

The National Center for Voice and Speech (NCVS) data bank on voice dosimetry was used to study the distributions of continuous voicing periods and silence periods in 31 teachers over the duration of two weeks. Recordings were made during all awake hours of the day. Voicing periods were grouped into half decades, ranging from 0.0316 to 0.10 s for the shortest periods of phonation to 31.6-100 s for the longest periods of phonation. Silence periods were grouped into similar half decades, but ranged up to periods of several hours. On average, the teachers had 1800 occurrences of voicing (onset followed by offset) per hour at work and 1200 occurrences per hour while not at work. Voicing occurred 23% of the total time at work, dropping to 13% during off-work hours and 12% on weekends. The greatest accumulation of voicing occurred in the 0.316-1.0 s voicing periods, whereas the greatest accumulation of silence occurred in the 3-10 s silence periods. The study begins to lay the groundwork for understanding vocal fatigue in terms of repetitive motion and collision of tissue, as well as recovery from such mechanical stress.

Prevalence of Voice Complaints, Risk Factors and Impact of Voice Problems in Female Student Teachers

A cross-sectional questionnaire survey was done among 457 female student teachers and 144 females in the general population. The conclusions are based on the opinions of student teachers and the general population. The results of this study show that 39.6% of the student teachers and 32.6% of the general population reported voice complaints at the moment and/or over the past year (p=0.198). The association between various risk factors (vocal loading factors, physical factors, environmental factors and psycho-emotional factors) and voice complaints were examined. Vocal load was reported in both the student teachers and the general population (p=0.322). Among the subjects with voice complaints, the student teachers were significantly more of the opinion than the general population that environmental irritants in the classroom (p=0.001) and the composition of the group they communicate with (p=0.033) have a negative influence on their voice. In the groups with voice complaints, the student teachers reported significantly less than the general population that stress (p=0.004) and the deterioration of their general physical condition (p=0.003) have a negative influence on their voice. Remarkably, over a third of the student teachers and one fifth of the general population with voice complaints were of the opinion that decrease of hearing has a negative influence on their voices (p=0.113). There was no significant difference in Voice Handicap Index (VHI) scores (p=0.284) and impact of voice complaints among student teachers and the general population. Over 15% of the student teachers and the general population with voice complaints reported being or having been disabled due to the voice problem, probably reflecting the severity of the voice problem (p=0.838). The groups reporting voice complaints and disability in relation to their voice complaints have significantly higher VHI scores than those without voice complaints and disability, which indicates a higher psychosocial impact of voice complaints. Only around a third of the student teachers and the general population with voice complaints sought paramedical care (p=0.656)/treatment (p=0.361) for their voice complaint. Only a minority of student teachers (18.6%) and the general population (29.5%) with voice complaints were of the opinion that the number of people they communicate with has a negative influence on their voice (p=0.120). Only around a third of the student teachers and less than a tenth of the general population with voice complaints were of the view that they would develop a voice complaint due to their profession (p=0.003). Less than half of the student teachers and less than one fifth of the general population with voice complaints were aware of the potential risks of their profession on their voice (p=0.002). Voice complaints appear to have a multifactorial genesis. The student teachers are not sufficiently aware of the impact of the various risk factors on their voice. Furthermore, they are not aware of the potential risk that future teaching may have on their voice. This apparent lack of awareness in student teachers may be considered a risk factor for voice complaints.

Development and testing of a portable vocal accumulator

This research note describes the design and testing of a device for unobtrusive, long-term ambulatory monitoring of voice use, named the Portable Vocal Accumulator (PVA). The PVA contains a digital signal processor for analyzing input from a neck-placed miniature accelerometer. During its development, accelerometer recordings were obtained from 99 participants with normal or dysphonic voices. The recordings were used to (a) test the specifications and capabilities of the PVA for monitoring normal and dysphonic voices and (b) explore potentially useful displays for the large quantity of data generated by long-term monitoring. The current prototype PVA is pocket-sized (12 x 8.5 x 2 cm), lightweight (200 g), and capable of sampling 11 hr of voice-use data, including estimates of fundamental frequency, sound pressure level, and phonation duration.

Methods to study pre-school teachers' voice at work: simultaneous recordings with a voice accumulator and a DAT recorder

Long-term recordings with reliable methods are desirable for objective documentation of voice use during natural conditions. The purpose of this study was to evaluate a voice accumulator (VAC) with a digital audiotape (DAT) recorder as a reference. The VAC is based on a microprocessor that accumulates information about fundamental frequency (F0) and phonation time. A contact microphone attached to the front of the neck registers vocal fold vibrations. The DAT recorder was connected to two microphones for airborne signals placed at equal distance from the mouth close to the subject's ears. The computer program Aura was used to separate the subject's voice from the background noise. The Soundswell program was used for F0 and phonation time analysis. Two tests were performed: 1) One female speech-language pathologist was recorded with the two devices simultaneously in a sound-proof booth. She read a standard text with different voice qualities and sustained vowels with increasing F0 and intensity separately. The results showed good agreement between the two methods with respect to F0 and phonation time. However, the VAC failed to register high frequencies above around 440 Hz as well as low intensities. 2) Three female pre-school teachers were recorded with the two devices simultaneously during a working day. Results showed high correlations between the two methods in terms of long-term measurements of F0 and phonation time for two subjects For one subject with subcutaneous soft tissue on the neck, the registration with the contact microphone was not reliable. It was concluded that the VAC has potential for assessment of occupational voice disorders if certain limitations of the method are considered.

Vocal dose measures: quantifying accumulated vibration exposure in vocal fold tissues

To measure the exposure to self-induced tissue vibration in speech, three vocal doses were defined and described: distance dose, which accumulates the distance that tissue particles of the vocal folds travel in an oscillatory trajectory; energy dissipation dose, which accumulates the total amount of heat dissipated over a unit volume of vocal fold tissues; and time dose, which accumulates the total phonation time. These doses were compared to a previously used vocal dose measure, the vocal loading index, which accumulates the number of vibration cycles of the vocal folds. Empirical rules for viscosity and vocal fold deformation were used to calculate all the doses from the fundamental frequency (F0) and sound pressure level (SPL) values of speech. Six participants were asked to read in normal, monotone, and exaggerated speech and the doses associated with these vocalizations were calculated. The results showed that large F0 and SPL variations in speech affected the dose measures, suggesting that accumulation of phonation time alone is insufficient. The vibration exposure of the vocal folds in normal speech was related to the industrial limits for hand-transmitted vibration, in which the safe distance dose was derived to be about 500 m. This limit was found rather low for vocalization; it was related to a comparable time dose of about 17 min of continuous vocalization, or about 35 min of continuous reading with normal breathing and unvoiced segments. The voicing pauses in normal speech and dialogue effectively prolong the safe time dose. The derived safety limits for vocalization will likely require refinement based on a more detailed knowledge of the differences in hand and vocal fold tissue morphology and their response to vibrational stress, and on the effect of recovery of the vocal fold tissue during voicing pauses.

[Vocal fold nodules. Risk factors in teachers. A case control study design]

Vocal nodules are structural lesions very common amongst professional voice users such as teachers. We have studied the risk factors that predispose the development of vocal nodules in teachers. Two hundred and forty-two teachers were selected: 120 with vocal nodules and 120 with normal vocal folds. Professional and personal factors as well as classroom environment were studied. A complete evaluation of the voice was performed, aerodynamic measures, tone and extension of the voice, acoustic analysis, perceptual evaluation of the voice as well as a videolaryngostroboscopy which was definitive in the diagnosis. Younger teachers with less years of teaching experience a greater have tendency to develop vocal nodules than the rest. Class-room's dryness, loudness and echo are correlated with the pathological group. The most relevant personal factors in the pathological group were previous vocal pathology, laryngeal surgery, nasal surgery and gastroesophageal reflux. Vocal intensity and vocal frequency ranks were shorter in the pathological group. We could also see that, fonatory flow was less effective in the pathological group.

Vocal loading among day care center teachers

Day care center teachers suffer from voice disorders more often than nurses do. Several risk factors may increase voice disorder prevalence of day care center teachers. The risk factors can be bound to their job content and manner of working i.e. having to raise their voice to attract the attention of the children and to offer them the possibility to perceive spoken information, or to the environment i.e. poor acoustics and excess background noise. The purpose of this study was to measure some of the risk factors for voice disorders of day care center teachers and of a control group (nurses); these were speaking times and speech levels. The background noise levels during activities and RASTI-values (Rapid Speech Transmission Index), i.e. measures of the acoustics of rooms, were also measured at the day care centers. It was found that day care center teachers use their voices more and with higher levels than nurses do. It was also found that the background noise levels are high, which is partly due to the poor acoustics (lack of sufficient attenuation) of the rooms. Control of excess background noise is of utmost importance both for speakers' speech production as well as children's speech recognition.

Vocal behavior and vocal loading factors for preschool teachers at work studied with binaural DAT recordings

Preschool teachers are at risk for developing voice problems such as vocal fatigue and vocal nodules. The purpose of this report was to study preschool teachers' voice use during work. Ten healthy female preschool teachers working at daycare centers (DCC) served as subjects. A binaural recording technique was used. Two microphones were placed on both sides of the subject's head, at equal distance from the mouth, and a portable DAT recorder was attached to the subject's waist. Recordings were made of a standard reading passage before work (baseline) and of spontaneous speech during work. The recording technique allowed separate analyses of the level of the background noise, and of the subjects' voice sound pressure level, mean fundamental frequency, and total phonation time. Among the results, mean background noise level for the ten DCCs was 76.1 dBA (range 73.0-78.2), which is more than 20 dB higher than what is recommended where speech communication is important (50-55 dBA). The subjects spoke on an average of 9.1 dB louder (p < 0.0001), and with higher mean fundamental frequency (247 Hz) during work as compared to the baseline (202 Hz) (p < 0.0001). Mean phonation time for the group was 17%, which was considered high. It was concluded that preschool teachers do have a highly vocally demanding profession. Important steps to reduce the vocal loading for this occupation would be to decrease the background noise levels and include pauses so that preschool teachers can rest their voices.

Voice changes during work: subjective complaints and objective measurements for female primary and secondary schoolteachers

The purpose of this investigation was to study voice changes during a working day. The subjects consisted of 33 female primary and secondary schoolteachers who recorded their first and last lessons during one school day. The subjects were studied both as one group and two subgroups (those with many and those with few voice complaints). Estimates of fundamental frequency (F0), sound pressure level (SPL), the standard deviations of these values (F0 SD; SPL SD) and F0 time (vibration time of vocal folds) were made. The most obvious change due to loading was the rise of F0 that was 9.7 Hz between the first and last lesson (P = 0.00). F0 increased more (12.8. Hz, P = 0.006) in the subgroup with few complaints.

A voice accumulator device: evaluation based on studio and field recordings

A voice accumulator is a portable device for long-term measurements of voice use in natural conditions. A contact microphone attached to the front part of the neck registers vocal fold vibrations. The purposes of the present study were: 1) to evaluate the voice accumulator's two measuring programs optimized for registration of fundamental frequency (F0) and phonation time, respectively; and 2) to test the voice accumulator for field recordings. Four healthy subjects were recorded in a sound-proof booth simultaneously with one contact microphone into a voice accumulator and one contact microphone into a computer. In terms of F0 and phonation time, the results showed that correlations between the voice accumulator's two measuring programs and a signal-processing program were high (r > or = 0.85) for all subjects but one. The inter-subject variability was large. A prerequisite for reliable vocal fold vibration detection by the voice accumulator was a careful placement and a firm attachment of the contact microphone on the neck. Four subjects were recorded with the voice accumulator during a working day. It was concluded that the voice accumulator is an overall good instrument for measurements of F0 and phonation time, and thus is useful for both clinical work and research.

Surgical versus non-surgical interventions for vocal cord nodules

BACKGROUND

Vocal cord nodules are bilateral swellings of the mid-portion of the membranous vocal folds. They are of variable size and are characterised histologically by thickening of the epithelium with a variable degree of inflammatory action in the underlying superficial lamina propria. They characteristically produce hoarseness. Treatment of vocal cord nodules aims to eliminate or reduce this hoarseness.

OBJECTIVES

To assess the effectiveness of surgery versus non-surgical interventions for vocal cord nodules.

SEARCH STRATEGY

We searched the Cochrane Controlled Trials Register (CCTR) and Medline (1966-2000), Embase (1974-2000), Biological Abstracts (1970-2000), Biological Abstracts RRM (Reports, Reviews and Meetings) on CD-ROM (1989-2000) and review articles.

SELECTION CRITERIA

Randomised and quasi-randomised trials comparing any surgical intervention for vocal cord nodules with non-surgical treatment or no treatment.

DATA COLLECTION AND ANALYSIS

No suitable trials were identified.

MAIN RESULTS

No studies fulfilled the inclusion criteria.

REVIEWER'S CONCLUSIONS

There is a need for high quality randomised controlled trials to evaluate the effectiveness of surgical and non-surgical treatment of vocal cord nodules.

Does classroom amplification aid comprehension?

Many classrooms are noisy and this interferes with listening and teaching. FM soundfield (FM) amplification systems have been developed which provide a uniform soundfield throughout the classroom and increase the speech-signal:noise ratio. The effect on comprehension of such a system was investigated. Forty-nine pupils (comprising the two top classes of a mainstream primary school) participated in this study, with a mean age of 9.92 years (range 8.58-11.42 years). The Neale Analysis of Reading Ability (Neale, 1988a, b) was modified and administered as a spoken comprehension test. Tests of nonverbal intelligence, auditory memory and a questionnaire were given. The passages spoken though the FM amplification system were understood better than the comparable unamplified passages. Auditory memory, sex and non-verbal intelligence had no effect on improved comprehension. FM amplification significantly improved comprehension and could be considered for use in other schools.

The "singing-acting" child: the laryngologist's perspective--1995

A survey of pediatric otolaryngologists about voice disorders in children suggests that approximately 1% of children examined were noted to have voice problems, and in only one fifth of these children (0.2%) were the voice problems related to professional use of the voice, such as singing. Direct flexible laryngoscopy was the sole method of examination for 80% of the children examined by these pediatric specialists. Voice therapy for 6 months was generally recommended (88%). The survey represents an estimated clinical experience of > 160,000 children per year, and it achieved a response rate of 40% of pediatric otolaryngologists (48/120). Results suggest that the use of video and stroboscopy for examination of the pediatric voice would enhance understanding and assure correct diagnosis and treatment.