Vocal loading

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Vocal loading is the stress inflicted on the speech organs when speaking for long periods. [1] [2] [3] [4] [5]

Contents

Background

Of the working population, about 13% have professions where their voice is their primary tool. [1] That includes professions such as teachers, sales personnel, actors and singers, and TV and radio reporters. Many of them, especially teachers, suffer from voice-related medical problems. In a larger scope, this involves millions of sick-leave days every year, for example, both in the US and the European Union. Still, research in vocal loading has often been treated as a minor subject.

Voice organ

Voiced speech is produced by air streaming from the lungs through the vocal cords, setting them into an oscillating movement. [6] [7] In every oscillation, the vocal folds are closed for a short period of time. When the folds reopen the pressure under the folds is released. These changes in pressure form the waves called (voiced) speech.

Loading on tissue in vocal folds

The fundamental frequency of speech for an average male is around 110 Hz and for an average female around 220 Hz. That means that for voiced sounds the vocal folds will hit together 110 or 220 times a second, respectively. Suppose then that a female is speaking continuously for an hour. Of this time perhaps five minutes is voiced speech. The folds will then hit together more than 30 thousand times an hour. It is intuitively clear that the vocal fold tissue will experience some tiring due to this large number of hits.

Vocal loading also includes other kinds of strain on the speech organs. These include all kinds of muscular strain in the speech organs, similarly as usage of any other muscles will experience strain if used for an extended period of time. However, researchers' largest interest lies in stress exerted on the vocal folds.

Effect of speaking environment

Several studies in vocal loading show that the speaking environment does have a significant impact on vocal loading. Still, the exact details are debated. Most scientists agree on the effect of the following environmental properties:

[8]

In addition, smoking and other types of air pollution might have a negative effect on voice production organs.

Symptoms

Objective evaluation or measurement of vocal loading is very difficult due to the tight coupling of the experienced psychological and physiological stress. However, there are some typical symptoms that can be objectively measured. Firstly, the pitch range of the voice will decrease. Pitch range indicates the possible pitches that can be spoken. When a voice is loaded, the upper pitch limit will decrease and the lower pitch limit will rise. Similarly, the volume range will decrease.

Secondly, an increase in the hoarseness and strain of a voice can often be heard. Unfortunately, both properties are difficult to measure objectively, and only perceptual evaluations can be performed.

Voice care

Regularly, the question arises of how one should use one's voice to minimize tiring in the vocal organs. This is encompassed in the study of vocology, the science and practice of voice habilitation. Basically, a normal, relaxed way of speech is the optimal method for voice production, in both speech and singing. Any excess force used when speaking will increase tiring. The speaker should drink enough water and the air humidity level should be normal or higher. No background noise should be present or, if not possible, the voice should be amplified. Smoking is discouraged.

See also

Related Research Articles

In linguistics, creaky voice refers to a low, scratchy sound that occupies the vocal range below the common vocal register. It is a special kind of phonation in which the arytenoid cartilages in the larynx are drawn together; as a result, the vocal folds are compressed rather tightly, becoming relatively slack and compact. They normally vibrate irregularly at 20–50 pulses per second, about two octaves below the frequency of modal voicing, and the airflow through the glottis is very slow. Although creaky voice may occur with very low pitch, as at the end of a long intonation unit, it can also occur with a higher pitch. All contribute to make a speaker's voice sound creaky or raspy.

The term phonation has slightly different meanings depending on the subfield of phonetics. Among some phoneticians, phonation is the process by which the vocal folds produce certain sounds through quasi-periodic vibration. This is the definition used among those who study laryngeal anatomy and physiology and speech production in general. Phoneticians in other subfields, such as linguistic phonetics, call this process voicing, and use the term phonation to refer to any oscillatory state of any part of the larynx that modifies the airstream, of which voicing is just one example. Voiceless and supra-glottal phonations are included under this definition.

Voice analysis is the study of speech sounds for purposes other than linguistic content, such as in speech recognition. Such studies include mostly medical analysis of the voice (phoniatrics), but also speaker identification. More controversially, some believe that the truthfulness or emotional state of speakers can be determined using voice stress analysis or layered voice analysis.

<span class="mw-page-title-main">Vocal cords</span> Folds of throat tissues that help to create sounds through vocalization

In humans, vocal cords, also known as vocal folds or voice reeds, are folds of throat tissues that are key in creating sounds through vocalization. The size of vocal cords affects the pitch of voice. Open when breathing and vibrating for speech or singing, the folds are controlled via the recurrent laryngeal branch of the vagus nerve. They are composed of twin infoldings of mucous membrane stretched horizontally, from back to front, across the larynx. They vibrate, modulating the flow of air being expelled from the lungs during phonation.

<span class="mw-page-title-main">Human voice</span> Sound made by a human being using the vocal tract

The human voice consists of sound made by a human being using the vocal tract, including talking, singing, laughing, crying, screaming, shouting, humming or yelling. The human voice frequency is specifically a part of human sound production in which the vocal folds are the primary sound source.

<span class="mw-page-title-main">Larynx</span> Voice box, an organ in the neck of amphibians, reptiles, and mammals

The larynx, commonly called the voice box, is an organ in the top of the neck involved in breathing, producing sound and protecting the trachea against food aspiration. The opening of larynx into pharynx known as the laryngeal inlet is about 4–5 centimeters in diameter. The larynx houses the vocal cords, and manipulates pitch and volume, which is essential for phonation. It is situated just below where the tract of the pharynx splits into the trachea and the esophagus. The word ʻlarynxʼ comes from the Ancient Greek word lárunx ʻlarynx, gullet, throat.ʼ

<span class="mw-page-title-main">Singing</span> Act of producing musical sounds with the voice

Singing is the act of creating musical sounds with the voice. A person who sings is called a singer or vocalist. Singers perform music that can be sung with or without accompaniment by musical instruments. Singing is often done in an ensemble of musicians, such as a choir. Singers may perform as soloists or accompanied by anything from a single instrument up to a symphony orchestra or big band. Different singing styles include art music such as opera and Chinese opera, Indian music, Japanese music, and religious music styles such as gospel, traditional music styles, world music, jazz, blues, ghazal, and popular music styles such as pop, rock, and electronic dance music.

Vocal cord nodules are bilaterally symmetrical benign white masses that form at the midpoint of the vocal folds. Although diagnosis involves a physical examination of the head and neck, as well as perceptual voice measures, visualization of the vocal nodules via laryngeal endoscopy remains the primary diagnostic method. Vocal fold nodules interfere with the vibratory characteristics of the vocal folds by increasing the mass of the vocal folds and changing the configuration of the vocal fold closure pattern. Due to these changes, the quality of the voice may be affected. As such, the major perceptual signs of vocal fold nodules include vocal hoarseness and breathiness. Other common symptoms include vocal fatigue, soreness or pain lateral to the larynx, and reduced frequency and intensity range. Airflow levels during speech may also be increased. Vocal fold nodules are thought to be the result of vocal fold tissue trauma caused by excessive mechanical stress, including repeated or chronic vocal overuse, abuse, or misuse. Predisposing factors include profession, gender, dehydration, respiratory infection, and other inflammatory factors.

<span class="mw-page-title-main">Reinke's edema</span> Medical condition

Reinke's edema is the swelling of the vocal cords due to fluid (edema) collected within the Reinke's space. First identified by the German anatomist Friedrich B. Reinke in 1895, the Reinke's space is a gelatinous layer of the vocal cord located underneath the outer cells of the vocal cord. When a person speaks, the Reinke's space vibrates to allow for sound to be produced (phonation). The Reinke's space is sometimes referred to as the superficial lamina propria.

<span class="mw-page-title-main">Bogart–Bacall syndrome</span>

Bogart–Bacall syndrome (BBS) is a voice disorder that is caused by abuse or overuse of the vocal cords.

<span class="mw-page-title-main">Hoarse voice</span> Voice disorder

A hoarse voice, also known as dysphonia or hoarseness, is when the voice involuntarily sounds breathy, raspy, or strained, or is softer in volume or lower in pitch. A hoarse voice, can be associated with a feeling of unease or scratchiness in the throat. Hoarseness is often a symptom of problems in the vocal folds of the larynx. It may be caused by laryngitis, which in turn may be caused by an upper respiratory infection, a cold, or allergies. Cheering at sporting events, speaking loudly in noisy situations, talking for too long without resting one's voice, singing loudly, or speaking with a voice that's too high or too low can also cause temporary hoarseness. A number of other causes for losing one's voice exist, and treatment is generally by resting the voice and treating the underlying cause. If the cause is misuse or overuse of the voice, drinking plenty of water may alleviate the problems.

"Voice therapy" or "voice training" refers to any non-surgical technique used to improve or modify the human voice. Because voice is a social cue to a person's sex and gender, transgender people may frequently undertake voice training or therapy as a part of gender transitioning in order to make their voices sound more typical of their gender, and therefore increase their likelihood of being perceived as that gender. Having voice and speech characteristics be in agreement with one's gender identity is often important to transgender individuals, whether their goal be feminization, neutralisation or masculinization. Voice therapy can be seen as an act of gender- and identity-affirming care, in order to reduce gender dysphoria and gender incongruence, improve the self-reported wellbeing and health of transgender people, and alleviate concerns over an individual being recognized as transgender.

Vocal cord paresis, also known as recurrent laryngeal nerve paralysis or vocal fold paralysis, is an injury to one or both recurrent laryngeal nerves (RLNs), which control all intrinsic muscles of the larynx except for the cricothyroid muscle. The RLN is important for speaking, breathing and swallowing.

Spasmodic dysphonia, also known as laryngeal dystonia, is a disorder in which the muscles that generate a person's voice go into periods of spasm. This results in breaks or interruptions in the voice, often every few sentences, which can make a person difficult to understand. The person's voice may also sound strained or they may be nearly unable to speak. Onset is often gradual and the condition is lifelong.

Puberphonia is a functional voice disorder that is characterized by the habitual use of a high-pitched voice after puberty, hence why many refer to the disorder as resulting in a ‘falsetto’ voice. The voice may also be heard as breathy, rough, and lacking in power. The onset of puberphonia usually occurs in adolescence, between the ages of 11 and 15 years, at the same time as changes related to puberty are occurring. This disorder usually occurs in the absence of other communication disorders.

Vocology is the science and practice of vocal habilitation, or vocal training and therapy. Its concerns include the nature of speech and language pathology, the defects of the vocal tract (laryngology), the remediation of speech therapy, and the voice training and voice pedagogy of song and speech for actors and public speakers.

The National Center for Voice and Speech (NCVS), is a multi-site research and teaching organization dedicated to studying the characteristics, limitations and enhancement of human voice and speech. The NCVS is located in Salt Lake City, Utah with the Lead Institution located at the University of Utah. NCVS is also a Center at the University of Iowa where it has laboratories in the Department of Speech Pathology and Audiology. In addition, the NCVS has collaborators in Denver and at many institutions around the United States. Its focus is vocology, or the science and practice of voice habilitation.

The vocal fry register is the lowest vocal register and is produced through a loose glottal closure that permits air to bubble through slowly with a popping or rattling sound of a very low frequency. During this phonation, the arytenoid cartilages in the larynx are drawn together, which causes the vocal folds to compress rather tightly and become relatively slack and compact. This process forms a large and irregularly vibrating mass within the vocal folds that produces the characteristic low popping or rattling sound when air passes through the glottal closure. The register can extend far below the modal voice register, in some cases up to 8 octaves lower, such as in the case of Tim Storms who holds the world record for lowest frequency note ever produced by a human, a G−7, which is only 0.189 Hz, inaudible to the human ear.

<span class="mw-page-title-main">Voice therapy</span> Used to aid voice disorders or altering quality of voice

Voice therapy consists of techniques and procedures that target vocal parameters, such as vocal fold closure, pitch, volume, and quality. This therapy is provided by speech-language pathologists and is primarily used to aid in the management of voice disorders, or for altering the overall quality of voice, as in the case of transgender voice therapy. Vocal pedagogy is a related field to alter voice for the purpose of singing. Voice therapy may also serve to teach preventive measures such as vocal hygiene and other safe speaking or singing practices.

Muscle tension dysphonia (MTD) was originally coined in 1983 by Morrison and describes a dysphonia caused by increased muscle tension of the muscles surrounding the voice box: the laryngeal and paralaryngeal muscles. MTD is a unifying diagnosis for a previously poorly categorized disease process. It allows for the diagnosis of dysphonia caused by many different etiologies and can be confirmed by history, physical exam, laryngoscopy and videostroboscopy, a technique that allows for the direct visualization of the larynx, vocal cords, and vocal cord motion.

References

  1. 1 2 Titze, IR; Lemke, J; Montequin, D (1997). "Populations in the U.S. Workforce who rely on voice as a primary tool of trade: a preliminary report". Journal of Voice. 11 (3): 254–9. doi:10.1016/S0892-1997(97)80002-1. PMID   9297668.
  2. ↑ Popolo, PS; Svec, JG; Titze, IR (2005). "Adaptation of a Pocket PC for use as a wearable voice dosimeter". Journal of Speech, Language, and Hearing Research. 48 (4): 780–91. doi:10.1044/1092-4388(2005/054). PMID   16378473.
  3. ↑ Titze, IR; Hunter, EJ; Svec, JG (2007). "Voicing and silence periods in daily and weekly vocalizations of teachers". The Journal of the Acoustical Society of America. 121 (1): 469–78. doi:10.1121/1.2390676. PMC   6371399 . PMID   17297801.
  4. ↑ Nix, J; Svec, JG; Laukkanen, AM; Titze, IR (2007). "Protocol challenges for on-the-job voice dosimetry of teachers in the United States and Finland". Journal of Voice. 21 (4): 385–96. doi:10.1016/j.jvoice.2006.03.005. PMID   16678386.
  5. ↑ Carroll, T; Nix, J; Hunter, E; Emerich, K; Titze, I; Abaza, M (2006). "Objective measurement of vocal fatigue in classical singers: a vocal dosimetry pilot study". Otolaryngology–Head and Neck Surgery. 135 (4): 595–602. doi:10.1016/j.otohns.2006.06.1268. PMC   4782153 . PMID   17011424.
  6. ↑ Titze, IR (2008). "The human instrument". Scientific American. 298 (1): 94–101. Bibcode:2008SciAm.298a..94T. doi:10.1038/scientificamerican0108-94. PMID   18225701.
  7. ↑ Titze, I.R. (1994). Principles of Voice Production, Prentice Hall (currently published by NCVS.org), ISBN   978-0-13-717893-3.
  8. ↑ Fujiki, RB & Sivasankar, MP (2016) A Review of Vocal Loading Tasks in the Voice Literature, Journal of Voice, In Press DOI: https://dx.doi.org/10.1016/j.jvoice.2016.09.019
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