AudioSync Pro Blog

In a JAMA article published this week (1), “The prevalence of hearing loss among a sample of US adolescents aged 12 to 19 years was greater in 2005 -2006 compared with 1988-1994.” Parents and many adults within earshot have complained about noise from music preferred by adolescents for decades. Proof of increased hearing loss in a young population may validate the concerns, and calls to question whether willful exposure to loud sounds such as music may be contributing to noise induced hearing loss in this population. The New York Times featured an article this Sunday (2) about noise pollution, describing how prolonged exposure can create difficulties with fatigue, concentration, productivity, sleep disturbances and stress.
The simple fact that others complain about loud music underscores the effects of noise beyond risk of hearing loss. Noise by definition is unwanted sound: the weeds in the acoustical garden of our daily life. Too much exposure to noise interferes with communication in the moment of exposure, annoys people to no end, creates health problems, and can eventually create hearing loss. Citing World Health Organization recommendations and his own research in New Zealand, David Welch, Ph.D. recently discussed “Noise Annoyance and Health Related Quality Of Life” (3) at the New Zealand Audiological Society meeting. Even relatively mild levels of noise, when intermittent, can alter arousal states, affect sleep, and create autonomic nervous system reactions contributing to cardiovascular and emotional disorders.
Prevention is the best approach to noise control, at the source by turning down the volume, or through engineering solutions such as quieter airplanes. The fact remains, however that there are a variety of sources of noise that can’t be, or don’t want to be turned down. In our capacity as hearing experts, we can not only make sounds more audible with hearing aids, we can reduce the impact of noise with careful selection of passive earplugs, or with even more carefully fitted electronic devices designed to allow for the reception of conversational speech yet limited to protect against potentially damaging loud sounds. Add to the electronic limiting a sophisticated fast-acting noise control that works to reduce the sound levels in between the syllables and pauses of speech and you have the potential to make a work or recreational environment much safer and pleasant for the device user.
Let’s take the example of Captain Lee. He is a construction tug boat captain, and has worked in that environment for decades. His work is such that he needs to stand out on the stern of his tug precisely moving a huge barge full or boulders for a crane operator so the boulders can be stacked to create a foundation for a jetty or other massive marine structure. The twin diesel exhaust stacks are screaming at 95+ dBA, and Captain Lee is simultaneously performing a ballet with tons of boat, barge and rocks while trying to pay attention to his crew, and listen to the radio for the crane operator and nearby vessels. Earplugs, while necessary, interfere with communication and aren’t the ideal solution for the captain. In addition to the problems onboard the tug, the captain was having increased difficulty with communication at home, especially in noisy environments.
A visit to the audiologist at his health plan produced test results like we might expect: normal hearing in the low frequencies through 1000 Hz, with a 35 dBHL loss at 2,000 Hz, sloping to 65dBHL at 3,000 and 4,000 Hz bilaterally. A common fitting of an open fit product was considered because it would likely help with social situations, but was recognized that it would be of little or no benefit on the tug. Following the captain’s highest priorities to promote comfort, communication and to prevent further hearing loss, while at work, an atypical approach to fitting was pursued. AudioSync 325 NT occluding CIC hearing aids (pressure 1mm vents only) were selected. The initial fitting was performed using the Integrated Real Ear Measurement system, with the “inexperienced” gain modification option selected because he is a new user. Slight gain and bandwidth modifications were necessary for sound quality. The output was reduced so that no loud sounds were judged to be uncomfortable at any time. The most aggressive fast-acting noise reduction settings were selected in an attempt to reduce the impact of noise when the environment didn’t drive the hearing aid into full limiting. The patient was loaned a simple sound level meter to document the environments he works in.
Initial reports from the patient at 24 hours and 3 weeks are very positive. He indicates that he is very comfortable on deck at work, and feels that his ability to focus on maneuvering the vessel and hear the radio is markedly improved. Socially, he looks to wear the hearing aids in the car, in noisy restaurants and at sporting events, but feels little benefit in quiet. The next step will be to activate additional memories to allow the hearing aids to provide more benefit in social situations.
Bottom line? With new technology, some creative approaches taking advantage of the new features available can bring more benefit and value to our patients. Maybe they will even sleep better at night…we plan to!
1. Shargorodsky J, Curhan SG, Curhan GC, Eavey, R. Change in Prevalence of Hearing Loss in US Adolescents. JAMA. 2010; 304(7):
2. http://www.nytimes.com/2010/08/16/business/energy-environment/16iht-green.html?_r=1 (8/17/2010)
3. http://www.audiology.org.nz/prof/pdfs/Aeroplane%20Noise.ppt (8/17/2010)