Is voice recognition dangerous for your health?

From...

May 23, 2000
Web posted at: 9:53 a.m. EDT (1353 GMT)

by Linda L. Grubbs

(IDG) -- Sometimes the remedy is as bad as the affliction. Take speech recognition software, which lets you dictate text into your PC instead of typing. For years, experts and vendors have recommended these products as an alternative to a keyboard, particularly for users with repetitive strain injuries or other ailments caused by too much typing.

But in the past few years, ergonomics experts have been treating patients with strained vocal cords that may be caused by improper use of these products. While no definitive link between speech recognition use and vocal cord damage has been established, at least one study indicates a correlation between the two, and speech pathologists say they're seeing more cases.

Why the increase? Vendors have taken enormous strides in making speech recognition software cheaper, easier to use, and a viable alternative to the keyboard/mouse combination. As a result, people are more likely to use the products. And the technology is expected to become more widespread as it becomes embedded in cell phones that can understand spoken commands and voice-controlled Web pages, which let you surf without typing, according to Krishna Nathan, director of Consumer Voice Systems at IBM.

The potential health problems are very real. If you use speech recognition products improperly, you can damage your vocal cords, resulting in chronic hoarseness, fatigue when speaking, and even a temporary loss of your voice.

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Representatives from Lernout & Hauspie, Dragon Systems, and IBM, the big three speech recognition vendors, say they are not aware of any vocal cord problems caused by their products. Bill Destafanis, product manager at L&H, said he's not denying that the problem exists, but the company hasn't received any customer complaints or comments about vocal cord problems from using L&H products.

But why take any chances? If you work with speech recognition software, you should know the warning signs of vocal cord injury and how you can protect yourself from harm.

The case against speech

In 1997, the Voice Laboratory and Speech Treatment Centre of Ontario and the University of Tennessee's Rehabilitation Engineering Program conducted a study of 70 patients who used discrete speech recognition products and had voice problems. Researchers noted that products from IBM, Dragon, and Kurzweil Applied Intelligence were among the most popular PC products in use at the time of the study.

Discrete speech products require you to pause... between ... each ... word and emphasize certain words as you dictate. If you use Dragon Dictate or IBM's VoiceType Dictation, you have a discrete speech product. Erica Danjelic, a San Francisco Hearing and Speech Center speech pathologist, says talking that way can hurt your vocal cords. Repeatedly emphasizing words can be tough on the voice as well.

The study suggested that these products may cause moderate to severe voice problems for some users. The researchers noted that the more people use speech recognition products, the more likely they are to develop voice problems.

The current generation of speech recognition products uses a newer technology called continuous speech. Products such as Dragon NaturallySpeaking, IBM's ViaVoice and L&H's Voice Xpress use this technology. With continuous speech, users dictate at a normal pace without having to pause between words. Based on her experiences, Danjelic believes continuous speech products are more conducive to the way people speak and therefore should reduce many problems associated with discrete speech products.

However, this doesn't mean you're immune from vocal cord damage. Lois Singer, director of the Voice Laboratory and Speech Treatment Centre of Ontario, a speech pathologist, and coauthor of the 1997 study, has seen 30 more patients with vocal cord problems since the original study was conducted. Some of these patients worked with continuous speech products.

More studies would have to be conducted to conclusively determine if there is a correlation between vocal cord problems and speech recognition software. But because the possibility exists, you should be aware of the telltale signs.

Warning signs

People can develop repetitive strain injuries of their vocal cords from using speech recognition products, in much the same way that people get injuries from typing too much, Singer reports. Constant repetitive tasks, such as talking or typing, tend to weaken muscles, sometimes resulting in a limited range of motion. When you overuse your larynx, it doesn't close, and you begin to strain the muscles in your neck to get them to close.

Look for these warning signs to determine if you're experiencing vocal cord problems. If you have these symptoms, immediately consult your doctor to determine a course of treatment.

CHRONIC HOARSENESS: That dry, scratchy throat or tickle you feel along the back of your windpipe could be your first sign of trouble.

NAGGING COUGH: This symptom often begins as a mild cough, and then turns into violent spasms that are difficult to get under control. These bouts can result in swollen and irritated vocal cords.

FATIGUE WHEN SPEAKING: When your vocal cords are worn out, varying the pitch of your voice becomes difficult, and you find yourself straining to get the words out. You may lose the ability to project or raise your voice. This symptom develops gradually, and it is more common in the later stages of vocal cord damage.

CONSTANT THROAT CLEARING: If you're constantly "ahem"-ing, take note: Clearing mucus from the larynx actually causes more irritation because it causes the vocal cords to bang together unnecessarily.

NECK MUSCLES ACHE: Tightness in your neck can indicate that you're using your neck muscles to get your vocal cords to close. Because of their weakened state, your vocal cords stay open, resulting in a gravelly voice.

NORMAL VOICE PITCH IS LOWERED: The pitch of your voice slowly lowers even when you're not using the software.

LOSS OF VOICE: This symptom occurs intermittently, but increases in frequency as the vocal cords lose their strength. Ultimately, you could completely lose the ability to speak except for short periods at a time.

These warning signals are indications you may have some problems. But you don't have to wait to feel them before you do something. You can protect your vocal cords by following a simple rule: Be kind to your voice.

Prevent problems

Speech pathologists and speech recognition experts say there's a right way and a wrong way to use speech recognition products. Here are a few tips for keeping your voice healthy while you talk your way through your work.

MIX IT UP: Use speech recognition software in conjunction with other products such as a keyboard and mouse or a pen and pencil, or use macros for commonly used key combinations. This prevents your vocal cords from becoming overly stressed.

AVOID USING A MONOTONE VOICE: Alter your pitch when speaking or dictating, and make sure that you get enough air. Air reaching your vocal cords enables them to vibrate more easily.

TAKE BREAKS: Treat your vocal cords as you would your wrists if you had repetitive strain injuries: Give your voice a rest by stopping frequently and taking breaks for silence. If you are feeling discomfort in your throat, stop immediately.

SPEAK NATURALLY: Don't talk loudly. Use a normal, conversational tone. Raising your voice strains your vocal cords.

AVOID CLEARING YOUR THROAT: Clearing your throat bangs your vocal cords together, just as coughing does, and it causes irritation. If you must clear your throat, make as little noise as possible.

MAINTAIN GOOD POSTURE: Do not sit hunched over. Keep your chin level: When you chin is tilted up, your vocal cords change position, and it is more strenuous to speak.

MONITOR YOUR ENVIRONMENT: Too much or too little humidity can have a negative effect on your vocal cords. Ideally, the room should have between 40 and 50 percent humidity.

BE MINDFUL OF MEDICATIONS: Some over-the-counter drugs, such as aspirin and antihistamines, can cause dry mouth, further irritating your vocal cords.

DON'T SQUINT: Narrowing your eyes to see the small print on your screen can actually hurt your voice as well as your eyesight. Squinting causes tension in the neck and face and adds strain to your vocal cords.

UPGRADE YOUR SOFTWARE: If you're using an older product that relies on discrete speech technology that requires you to pause between each word, consider upgrading to a continuous speech product that lets you dictate more naturally.

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