Noise Induced Hearing Loss Due To Regular, Sustained Usage of Headphones

While our discussion until now has been common to any common computer user/transcriber, the following discussion is going to be unique to medical transcriptionists and call center executives who have to wear headphones in their daily chores. Too much of sound banged into our ears over a long period of time is bad too but we have to tackle it with some lifestyle changes. Let’s discuss how.

The following is a chart of sounds often heard in our everyday life:

• Ringing telephone, 60 dB
• Normal conversation at 3-5 feet, 60-70 dB
• Restaurant, 70 dB
• Dial tone of a telephone, 80 dB
• Heavy city traffic, alarm clock at 2 feet, factory noise, vacuum cleaner, garbage disposal, 80 dB
• Motorcycle, workshop tools, 90 dB
• Subway train at 200 feet, 95 dB
• Chain saw, pneumatic drill, 100 dB
• Power mower, 107 dB
• Dance club, 110 dB
• Rock concert speaker sound, sandblasting, thunderclap, 120 dB
• Jet engine at 100 feet, 140 dB
• Loudest sound that can occur, 194 dB
• OSHA monitoring requirement begin, 90 dB
• Regular sustained exposure may cause permanent damage, 90-95 dB
• Pain begins, 125 dB

Find below the chart pertaining to duration of occupational noise exposure in hours per day a person can be subjected to as per OSHA.

OSHA Regulation 1910.95 - Occupational noise exposure

• 90 dbA 8 hrs
• 92 dbA 6 hrs
• 95 dbA 4 hrs
• 97 dbA 3 hrs
• 100 dbA 2 hrs
• 102 dbA 1.5 hrs
• 105 dbA 1 hr
• 110 dbA 0.5 hr
• 115 dbA 0.25 hr or less

Hearing damage from headphones is probably more common than from loudspeakers, because many people exploit the acoustic isolation by listening at higher volumes. Damaging levels can easily be reached under headphones, and the prevalence of noise induced hearing loss (NIHL) from headphone use is highly correlated with length of exposure. Moreover, the risk of hearing damage from headphones is higher than with loudspeakers, even at comparable volumes, due to the close coupling of the transducers to the ears.

In loudspeaker reproduction, sounds must travel several feet before reaching the listener’s ears. By the time they arrive, a portion of the high frequencies have been absorbed by the air. Low frequencies are not absorbed as much, but they are more felt through bone conduction than actually heard. With headphones, the ears hear all frequencies without any attenuation, because the transducers are literally pressed against them. Thus, when listening to headphones at the same effective volume level as loudspeakers, headphones may still transmit louder high frequencies that are more likely to cause hearing damage. When a person is exposed to loud noise over a long period of time, symptoms of NIHL will increase gradually. Hearing phenomenon that seems to be more noticeable with headphones is a decreasing sensitivity to sound levels over time, as the ears adapt to loud sounds. The listener perceives a gradual drop in loudness even though the volume control setting hasn’t changed. Over time, the sounds a person hears may become distorted or muffled, and it may be difficult for the person to understand speech. The acoustic isolation of headphones tends to highlight this dulling effect. It is all too easy for headphone listeners to turn up the volume to the point where hearing is at risk. Interestingly, most people find it difficult to distinguish between 85dB and 100dB sound pressure levels, despite that the latter is more injurious to hearing.

Hence, hearing damage can be gradual, cumulative and without obvious warning signs. Someone with NIHL may not even be aware of the loss, but it can be detected with a hearing test. A hearing test and a medical examination are the only way to truly diagnose hearing damage. However, the following symptoms are serious enough to warrant an appointment with the ear doctor:

• Ringing or buzzing in the ears.
• Difficulty in understanding speech.
• Slight muffling of sounds.
• Difficulty understanding speech in noisy places or places with poor acoustics.

More severe symptoms of hearing damage can include acute or chronic dizziness, pain, discomfort, and drainage from the ears. In the case of severe acoustic trauma, an immediate visit to an ear doctor or the Emergency Room of a hospital is in order. There are medications that when given in time may minimize hearing loss.

Here are a few tips that you can adopt in your daily routine to go by the saying “prevention is better than cure.”

Avoid listening fatigue by resting the ears in silence after long sessions with headphones and to fight the temptation to turn up the volume. Lower the volume to the lower threshold limits whenever possible that you just clearly hear without any jarring effect. For this, the surrounding atmosphere should be calm too. Set headphone volumes at an average of 60-70 dB, a little less than the average sound level in a restaurant. With open-air headphones, the ability to hear normal conversation through the headphones is a good indicator that the volume level is safe. Because closed-ear headphones acoustically isolate the listener, normal conversation may not be audible when wearing these types of headphones. Instead, a safe volume level may be set by moving one earcup off and comparing the level in other earcup with that of normal conversation.

As said early, sleep is a good rejuvenator, sleep at least eight hours a day. Avoid being in front of computer monitor at least two hours before you get into your sleep sac.

Earwax blockage may be a problem too. Ear, nose and throat doctors recommend using mild treatments such as mineral oil, baby oil, glycerin, or commercial ear drops to soften earwax.

Adults too can get ear infection, otitis media, which is common for children. You can help prevent otitis media by washing your hands frequently. Also, get a flu shot every year to stave off respiratory infections. If you still get an ear infection, see a doctor immediately before it becomes more serious.

If you take medication, ask your doctor if your medicine is ototoxic, or damaging to the ear. Ask if other drugs can be used instead. If not, ask if the dose can be safely reduced. Sometimes it cannot. However, your doctor will help you get the medicine you need while trying to reduce unwanted side effects.

Electromagnetic radiation from VDUs
Lastly, there is the concern about the exposure to electromagnetic radiation from VDUs. This is the same concern expressed about microwave ovens, cellular phones, and even high voltage power lines. It is known that these forms of radiation do have effects on health, but current research is contradictory and inconclusive about the health effects of “household” electromagnetic radiation. The next wave of health concerns focuses on electromagnetic fields and the cathode ray tube in the computer screen showering us with negatively charged electrons. But don’t let that keep you up at night. It’s best to follow all the preventive steps listed from the beginning of this article, which by the way are things you can do without spending a penny.

Miscellaneous
The other concern of medical transcription career is the monotony that steps in after a period of time. This could only be overcome by indulging in activities like training new comers, writing books of your experience, organizational work etc.

Apart from these, we do have the hazards like heart problems etc., secondary to our sedentary lifestyle and since it is not associated with computer, let us discuss it later.

Also don’t forget to read ergonomics for MTs and computer users Part 1, Part 2 and Part 3.

Related Posts:

Ergonomics For Computer Users And Medical Transcriptionists

Ergonomics For Computer Users And Medical Transcriptionists Part 3

Ergonomics For Computer Users And Medical Transcriptionists Part 2