I know from experience hunting without ear plugs is hard on your ears, but I wondered how bad headphones were. Hearing loss is more common than ever before. About 16% of American adults have an impaired ability to hear speech, and more than 30% of Americans over age 20 — an estimated 55 million people — have lost some high-frequency hearing, according to a study published in the Archives of Internal Medicine. There is huge variation in how people are affected by loud sound, however, and this is an area where a number of researchers are conducting studies. Certainly a huge part of this is underlying genetics.
We know how much sound causes how much hearing loss based on studies that were conducted in the late '60s and early '70s, before employers were required to protect workers' hearing in noisy work environments. What was found is that when people are exposed to a certain level of noise every day for a certain duration, they're going to have a certain degree of hearing loss on average. “The outer hair cells in the cochlea, when exposed to loud noise, initially experience transient damage that causes a temporary threshold shift in the hearing; if the person is exposed long enough, the damage becomes permanent” (Kenna). But the amount of hearing loss might differ by as much as 30 dB between people who had the toughest ears and those with the most tender ones — a huge variation.
Another interesting thing I learned was how much bacteria built up in your ears when you shared headphones or used them for long periods of time. I found a comparative analysis of bacterial growth with earphone use. In the study they took 50 males and split them up into two groups. Group A rarely or infrequently used earphones and group B used earphones very frequently. Not surprisingly, both groups had an increase after using headphones, but group B had a lot more growth. Their study found “Frequent and constant use of earphones increases the bacterial growth in the ear and sharing of earphones might be a potential vector of commensals. It is therefore, always better not to share or else to clean the earphones before sharing” (Mukhopadhyay).
Reference:
Blue, Laura. "How Bad Are IPods for Your Hearing? - TIME." Breaking News, Analysis, Politics, Blogs, News Photos, Video, Tech Reviews - TIME.com. 28 July 2008. Web. 25 Nov. 2011.
Kenna, Margaret A. "Music to Your Ears: Is It a Good Thing?" Acta Paediatrica 97.2 (2008): 151-52. Print.
Mukhopadhyay C, Basak S, Gupta S, Chawla K, Bairy I. A comparative analysis of bacterial growth with earphone use. Online J Health Allied Scs. 2008;7(2):4
Reading this post made me wonder why our ears ring. Tinnitus is a "ringing, swishing, or other type of noise that originates in the ear or head."[1] Tinnitus is quite common and most individuals will experience it at some point in their lives. Tinnitus can be caused by several different things: loud noise, drugs, head trauma, ear wax build up, or ear infections.
ReplyDeleteThere are different kinds of tinnitus. Subjective tinnitus is when a patient hears an abnormal sound while objective tinnitus is when someone else can hear the sound coming from the patient. Subjective tinnitus is common from hearing loss. When the stereovilli on vestibular hair cells become damaged they cannot move and cause an action potential which is send to the brain for processing. One theory is that this damage causes the brain to receive abnormal signals and the brain becomes confused and develops its own noise to make up for the abnormal signal.
Objective tinnitus can arise from muscle spasms around the ear or movement of bones in the ear or head. Another type of objective tinnitus is called pulsatile tinnitus. This sound is heard as the heart beats and arises from altered blood flow or increased blood turbulence near the ear. I never realized that there are so many different types of tinnitus and if you listen really hard you can hear some of these different tinnitus.
[1] Tinnitus. eMedicineHealth. http://www.emedicinehealth.com/tinnitus/article_em.htm.