Occupational Vocal Health: An Emerging Workplace Wellness Issue

The topic has gained increasing attention in this country, with 2007 seeing the first-ever International Conference on Occupational Voice Research in San Antonio.

The voice is the primary occupational tool for many professions, yet rarely do we think about the demands placed on the human voice. If a famous singer cancels a concert tour due to a voice problem—that might make the news. Yet every day, millions of Americans spend the majority of their work day using their voice in some capacity, especially workers such as salespersons and schoolteachers. What happens if their voices don't function properly? Some might be able to get by temporarily, but for many employees, having a voice that is rough, tired, hoarse, or nonexistent means they cannot perform their job at an acceptable level.

In 1997, it was estimated that schoolteachers made up only 4 percent of the U.S. workforce yet made up 20 percent of the caseload in voice clinics.1 A 2001 article estimated that as many as 28 million workers in the United States experience voice problems on a daily basis, and more surprisingly, that the voice problems in teachers alone resulted in an annual cost to society of $2.5 billion.2

In the fields of speech pathology and otolaryngology, the concept of work-related vocal injury is nothing new. Voice therapists and ENT physicians see clients daily with complaints of hoarseness, vocal fatigue, and voice loss unrelated to upper respiratory infections, allergies, or smoking. These vocal problems are quite often the direct result of either the type or sheer amount of voice use required by their profession. Often these injuries are temporary, equivalent to a muscle sprain in an athlete: with rest and perhaps some simple therapeutic exercise, function will return. However, some vocal injuries are more serious, causing damage to delicate vocal fold tissues that could take weeks or months to heal or even require surgical intervention. Some vocal injuries can cause permanent scarring, which may prevent the voice from ever returning to normal.

The topic of occupational vocal health has gained increasing attention in this country, with 2007 seeing the first ever International Conference on Occupational Voice Research in San Antonio, Texas, which was sponsored in part by a grant from the National Institutes of Health.3 At that conference, it was clear that some European countries were ahead of the United States regarding educating workers and employers and were moving toward legislation that would address the issue of vocal health on the job and protect workers whose voice was a primary occupational tool. Comparisons have been made to the field of audiology and the Occupational Safety and Health Administration standards regarding safe limits for occupational noise exposure. Recently, the speech pathology and voice science communities have begun to be more outspoken regarding the goal of defining what constitutes a safe "dose" of voicing, much in the same way safe doses of noise or safe doses of hand or limb vibration from industrial tools have been defined.4

Voicing is produced by vibration of the vocal folds, which typically collide at a rate of 100-200 Hz, and no other tissue in the human body is known to undergo the same rates of acceleration and deceleration, shearing forces, and collision stresses. Much remains to be learned about how vocal folds respond to these stresses or what the limits are for safe vocalization, while factoring in other issues such as loudness, vocal pitch level, and recovery times. A new area of voice research is now emerging, referred to as vocal dosimetry. While several devices have been reported in the research literature, there is now a growing demand for a commercially available vocal dosimeter, called the Ambulatory Phonation Monitor, that is being used for research and clinical purposes for patients with voice disorders.5 For the first time, it is possible to perform real-time monitoring of the accumulated vocal dose in humans over hours or even days, and it is expected that researchers will begin to define more clearly the effects of heavy voice use and what constitutes a healthy range of vocal doses.

Because for now many of the questions regarding a safe vocal dose remain unanswered, and there are no formal regulations in the United States that address the issue of occupational vocal health, the question remains: What can employers and employees do to ensure vocal health on the job? While there are numerous other factors that will certainly influence someone's vocal performance on the job, such as overall medical health, recreational voice use, and perhaps even "vocal genes," there are some straightforward ways to address vocal health on the job.

1. Check the noise, irritant, and humidity levels. These are issues that can be addressed under current OSHA guidelines. Having to speak for long periods over even moderate levels of noise can fatigue the voice. People naturally raise their pitch and volume when trying to speak over noise, both of which increase the vocal dose, in terms of the frequency and intensity of vocal fold tissue collisions. Inhaled respiratory irritants can also create problems for the voice by causing irritation and inflammation of the vocal folds' outer tissue layers. Irritants also can encourage frequent coughing and throat-clearing, both of which are traumatic to the vocal folds. Finally, excessively dry environments may also affect the voice by drying the outer vocal fold layers, making them less pliable and requiring more effort to sustain vibration.

2. Amplification. With teachers who complain of voice problems and vocal fatigue from long hours teaching, simply providing them with an inexpensive personal voice amplifier has been shown to be as effective as voice therapy or improving their overall vocal health in many cases.6,7 It is believed that amplifying the voice can be an effective way to reduce the overall vocal dose during long periods of voice use. Many school districts are finding ways to provide voice amplifiers for their teachers, through small grants or parent-teacher organizations. In some cases, insurance companies will pay for a voice amplifier for someone with a documented voice disorder and a letter from a speech-pathologist or physician declaring its medical necessity. FM systems, which are used in many settings already for hearing-impaired individuals, are a more costly alternative but ensure that anyone using the space will have an adequate voice signal-to-noise ratio for both the listeners and for the reduction of vocal dose.

3. Vocal hygiene. This is a new concept for many people and conjures up images of brushing and flossing one's larynx. Vocal hygiene simply means minimizing sources of potential vocal trauma, or what many speech pathologists call "too much, too loud, too often," and maximizing habits that take the load off the voice and keep the vocal folds themselves as healthy as possible. These include things such as avoiding shouting and chronic throat-clearing, as well as managing acid reflux (which can irritate the larynx) and maintaining adequate fluid intake for hydration. Incorporating short periods of vocal rest throughout a work day, providing much-needed recovery time for the constantly vibrating vocal fold tissues, is believed to be crucial, as well.

Another effort in this country supported by the National Institutes of Health was the development in 2003 of a Web site called the Voice Academy, which calls itself "a no-cost, self-directed, virtual school built for the vocal health of U.S. teachers."8 The Web site promotes vocal health for schoolteachers and includes basic education in vocal hygiene. While designed for teachers, it contains information that could be valuable for anyone in a profession that relies on heavy voice use. In addition to this Web site, employers can rely on the resources in their own community by inviting a speech pathologist to conduct vocal health screenings and provide brief educational seminars on taking care of the voice on the job.

As awareness of the need for vocal health on the job increases, it is important for employers to think about the demands certain professions make on the human voice. Loss of voice due to workplace vocal strain can be considered a recordable OSHA event, and in some states, may be compensable under worker's compensation law. Employers need to both empower and advocate for their employees to maintain good vocal health and prevent vocal meltdowns on the job. A good place to start would be to incorporate information about vocal health and ways to prevent vocal strain on the job into existing workplace wellness programs.

Our voices are rarely thought of until they don't function as expected. We should pay more attention to the care and maintenance of our two tiny vocal folds, which, although only as long as a thumbnail and as wide as a matchstick, can teach an entire class, make the sale of a lifetime, or persuade an audience of thousands.

1. Titze IR, Lemke J, Montequin D. Populations in the U.S. workforce who rely on voice as a primary tool of trade: a preliminary report. Journal of Voice. 1997;11:254-59.
2. Verdolini K, Ramig LO. Review: occupational risks for voice problems. Logopedics, Phoniatrics, Vocology. 2001;26:37-46.
3. Nix J. International Conference on Occupational Voice Research. 2007. http://projects.dlc.utsa.edu/ovc/. Accessed on Oct. 12, 2008.
4. Titze IR. Toward occupational safety criteria for vocalization. Logopedics, Phoniatrics, Vocology. 1999;24:49-54.
5. Hillman RE, Heaton JT, Masaki A, et al. Ambulatory monitoring of disordered voices. Annals of Otology, Rhinology & Laryngology. 2006;115:795-801.
6. Roy N, Weinrich B, Gray SD, et al. Voice amplification versus vocal hygiene instruction for teachers with voice disorders: a treatment outcomes study. Journal of Speech, Language, and Hearing Research. 2002;45:625-38.
7. Roy N, Weinrich B, Gray SD, et al. Three treatments for teachers with voice disorders: a randomized clinical trial. Journal of Speech, Language, and Hearing Research. 2003;46:670-88.
8. Ostrem J, Voice Academy. 2003. http://www.uiowa.edu/~shcvoice/. Accessed on Oct. 12, 2008.


This article originally appeared in the July 2009 issue of Occupational Health & Safety.

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