Stereos, MP3s, and Hearing Loss: Interview with Brian J. Fligor, ScD
Douglas L. Beck, AuD, speaks with Dr. Fligor about personal stereo systems, MP3 players, hearing loss secondary to long-term and loud exposure to music via personal stereo systems.
Academy: Good Morning, Brian.
Fligor: Hi, Doug.
Academy: Brian, I heard a rumor that you were actually an engineer as an undergrad, and then you saw the light and became an audiologist?
Fligor: Yes, that’s true. Like you, Doug, I’ve been playing guitar since I was a little kid. Music is an enormous part of my life and who I am. Frankly, engineering seemed like it was what I wanted to do, but it became boring and dry, not my preferred style. Audiology allowed me the advantages of working with sound and people, and, to me, audiology represents the marriage between music and health care.
Academy: Okay, we’ll go with that! Brian, tell me about the recent study you were involved with regarding personal stereo systems?
Fligor: The project was actually a comprehensive examination research project by Cory Portnuff, who worked with his advisor Kathryn Arehart and me. Cory finished his AuD this past year and is now a PhD candidate at the University of Colorado at Boulder and I’m on his dissertation committee. Nonetheless, the project is about adolescent use of MP3 players and the hazard to hearing. So we wanted to discern what factors make some people listen at quieter or louder levels, and what percentage of people put themselves at risk for music-induced hearing loss, and does their demographic profile impact their listening behavior?
Academy: And, of course, teenage boys listen with the settings maxed out.
Fligor: Yes, that’s a fairly true statement. Teenage boys do listen the loudest. In a previous study, Terri Ives and I examined young adults and their chosen listening levels. We found about 6 percent of the people listening in quiet were listening in excess of 85 dBA. However, when we put them in background noise, such as 80 dBA, such as in a jet plane cabin, a full 80 percent of the listeners cranked it way up and were listening too loud.
Academy: Basically due to masking?
Fligor: Yes. But we also learned that regardless of the specific background noise, adults and young adults seem to prefer a 13 dB signal-to-noise (SNR) ratio.
Academy: For music under headphones?
Fligor: Yes. The 13 dB SNR seems to be the goal for adults using any headphone system (earbuds, headphones, or inserts) while listening to music.
Academy: And so, Cory took those findings and applied them to teenagers?
Fligor: That’s right. One thing he added into the mix was a questionnaire, based on the “Health Belief Model” to assess the teenagers’ knowledge, attitude, and beliefs, all of which helps us predict who is most likely to engage in risky behavior. So he rounded-up about 29 teenagers with an average age of 14.5 years (12 males, 17 females). The inclusion criteria mandated that they listened to their personal listening device at least two hours per week.
Academy: Okay, and what did you learn?
Fligor: First, we learned that the isolating earphones didn’t consistently fit these young people very well, so sometimes they didn’t get as much sound isolation as adults did. But, more importantly, their absolute chosen listening levels were about 7 dB higher than the adults.
Academy: So rather than the previously established 13 dB SNR, they’re actually listening at 20 dB SNR?
Fligor: Yes, some do, not all. Of course, there was variation, and the standard deviation was large, but yes, we did find they chose a higher SNR than did the adults in the Fligor and Ives study.
Academy: Of course there are many immediate implications about noise-induced, or rather, music-induced hearing loss. Nonetheless, I recall Crandell, Smaldino, and Flexer’s book (Sound Field Amplification, Singular Publishing), when they noted something like adults with normal hearing and normal listening skills need a 6 dB SNR to perceive intelligible speech. However, because children are developing and maturing their cognitive, neurologic and particularly their auditory systems, even normal hearing children needed a much more favorable SNR.
Fligor: Right. So perhaps they do prefer a louder presentation for those reasons you mentioned. But, we can state unequivocally, teenagers do listen louder and their noise dose (based on the average amount of time they listen) in some 7 to 24 percent of the teens we studied, exceeded recommended noise exposure limits. So in fact, those teens were at risk for hearing loss secondary to using their personal listening systems.
Academy: Very interesting work. What else did you find?
Fligor: One other thing that came from the questionnaire was that teens who had perceived their susceptibility to hearing loss, and for the severity of hearing loss, as higher, actually listened louder. That’s of course contrary to rational thought! I think we can safely assume that in general, if you perceive your own susceptibility and risk as higher, that you would listen quieter—but that didn’t happen. Fortunately, though, teenagers who understood the benefits of decreasing their volume levels did have lower chosen listening levels.
Academy: What do you attribute these findings to?
Fligor: Probably the thrill of engaging in risky behavior and perhaps peer pressure. It’s also possible that teenagers are not adequately monitoring their listening levels, and don’t realize that they are actually putting themselves at risk for music-induced hearing loss.
Academy: Sounds like the basis of a follow-up study.
Fligor: Absolutely. We’ve got more work to do to figure all this out. But, we do know that the teens listen louder, and they’re at risk for permanent hearing loss, and despite their own suspicions that they might be doing themselves some harm, they still do it.
Academy: Brian, this is really interesting work. I’m very appreciative of your reviewing this with me.
Fligor: My pleasure, Doug.
For consumer-friendly information about noise-induced hearing loss, visit the Academy’s public awareness campaign, Turn It to the Left, Web site: www.TurnIttotheLeft.com.
Brian Fligor, ScD, is the director of diagnostic audiology at Children's Hospital Boston and an instructor in otology and laryngology at the Harvard Medical School.
Douglas L. Beck, AuD, Board Certified in Audiology, is the Web content editor for the American Academy of Audiology.
For More Information, References and Recommendations:
Fligor B J and Ives TE. (2006, October). Does headphone type affect risk for recreational noise-induced hearing loss? Paper presented at the NIHL in Children Meeting, Cincinnati, OH. Lay-paper retrieved December 31, 2007.
Portnuff CDF and Fligor BJ. (2006, October). Sound output levels of the iPod and other MP3 players: Is there potential risk to hearing? Paper presented at the NIHL in Children Meeting, Cincinnati, OH. Lay-paper retrieved December 31, 2007.
Fligor BJ. (2009). Do Headphones Cause Hearing Loss? Risk of Music-Induced Hearing Loss for the Music Consumer. In. M. Chasin (Ed.), Hearing Loss in Musicians, Prevention and Management. (pp 53-61).San Diego, CA. Plural Publishing, Inc.