Interview with David Lipscomb Ph.D., Consulting Audiologist, Correct Service, Inc.
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AO/Beck: Good evening Dr. Lipscomb. It's a pleasure to speak with you. How are you this evening?
Lipscomb: Doing fine thank you. Thanks for the opportunity.
AO/Beck: My pleasure. Let's start with a little about your history. When did you get your Ph.D.?
Lipscomb: I earned my Ph.D. at the University of Washington in Seattle in 1966. Prior to that I worked at the University of Tennessee back in the days when their Speech and Hearing Clinic was actually a private entitiy, funded in part by the state. I was in Tennessee for some 20 years, but my roots in Washington are rather deep. Additionally, I am a lecturer for the University of Florida Au.D. distance education program and I've done a few recorded classes for them.
AO/Beck: Actually, I was one of the students in the second class at the University of Florida Au.D. program. I viewed and studied those videos and we used your book as the class text (Hearing Conservation in Industry, Schools and the Military. Singular Publishing). I am one of those students that tends to write in books and highlight important passages. Resultantly, the whole book is yellow and pink. I learned a lot, but my copy of the book has no resale value in the used book stores!
Lipscomb: That's kind of you to say.
AO/Beck: How did you get interested in Hearing Conservation and legal issues related to audition?
Lipscomb: The first time I dealt with issues relating to high levels of sound was probably about 1965. At that time we had gone to the YMCA to go swimming and as we gathered in the lobby of the YMCA. I heard this horrible noise eminating from the gymnasium. When someone opened the door to enter the gym, the noise nearly knocked us over. Of course it was rock'n'roll, and that got me very interested in the effects of loud noise on the human ear. Prior to that event, I never thought much about it. So that was actually the beginning of my career. Then, when I was working on my Ph.D., noise was the area I became very interested in. Shortly after that, I was asked to investigate a community noise problem where a small iron works company became a large iron works company. One of the residents of that community, who happened to be an attorney, found it distressing to have noise coming from the plant 24 hours a day and 7 days a week and he asked me to look into that. So I got involved based on opportunities which actually presented themselves to me. Another incident which happened at the beginning of my career involved an attorney friend of mine who was representing a fellow who was accused of pulling in front of a speeding police car. The police officer was actually paralyzed from the waist down as a result of the accident. As we examined the parameters, it turned out that the fellow had pulled out with the green light and the issue became why didn't he react to the siren? So we reconstructed the scene with attention to issues like...
Could he indeed hear the siren? Was the siren sufficiently loud and of the right pitch? Did the fellow have the hearing acuity to hear the siren? And on and on, so there were many fascinating questions and as a result, the investigation became very intense and highly thought provoking.
AO/Beck: These incidents were all before the Walsh-Healy Act?
Lipscomb: Yes, these cases were in the mid-1960s. The Walsh-Healy Public Contracts Act was passed in 1969. The Walsh-Healy was the first comprehensive, federally mandated hearing conservation act backed by federal law. As you know, the Walsh-Healy Act initially only impacted some ten-thousand firms that were doing business with the federal government. That regulation became the basis of the 1972, so called Occupational Safety and Health Act (OSHA). In fact, the Walsh-Healy Act was inserted into that word-for-word. I think most people are familiar with OSHA, but the history may be a little unknown. By the way, OSHA does not stand for Our Savior Has Arrived! Of course the OSHA act applied to just about every employer and employee, so it had a far greater impact. So getting back to the original question, I was interested in noise because it was topical and news worthy while I was finishing my studies.
AO/Beck: What about your involvement with the Environmental Protection Agency (EPA)? Can you tell me a little about that?
Lipscomb: In 1973 or so, I was essentially 'on loan' from the University of Tennessee to the EPA Office of Noise Abatement and Control, for a summer exchange program. There, I had the opportunity to observe the generation of federal regulations in response to the Noise Control Act of 1972. While I was there, I made some terrific friendships which I still hold dear today. I had the opportunity to review and prepare documents with Dix Ward, Alice Suter, Art Taylor and Simone Yaniv. The five of us were charged with the preparation of the 1973 Criteria Document, which was prepared by the Office of Noise Abatement and Control, which summarized pretty much what was known about noise at the time. The next year, 1974, we prepared the so-called Levels Document, which was the EPA document that indicated the requisite sound pressure levels, consistent with health and safety for workers with a 'reasonable margin of safety'. The EPA got a bit of a 'bad rap' because some folks were saying that if 'everyone' was truly going to be protected, and if there was to be an additional margin of safety, nobody should be exposed to a lifetime Leq of greater than 70 dB, which is of course, not realistic. So the EPA and the OSHA regulations had about the longest gestation period of any regulations you can imagine. I think it was eleven years until the final regulations came out on March 8, 1983, which defined step-by-step what a Hearing Conservation Program should consist of.
AO/Beck: In this modern age of home computers and word processing excellence, it's hard to imagine a bunch of people sitting around a type-writer trying to agree on wording. You guys must've used a lot of white out!
Lipscomb: It's an amazing history because back then, the secretaries were so poorly trained, and they had such poor equipment, that we often typed things ourselves. Although I can type quickly - it's not very accurate! So to get a neat and clean document out took a great deal of effort, revision and retyping.
AO/Beck: And to further complicate things, this was during the Nixon era and there were lots of political and social things going on in and around Washington DC.
Lipscomb: Funny you should mention that. We had an office that was in Crystal City in Arlington. So we actually did look out of the window from our office and we could see the helicopter lift off of the White House lawn when it lifted Nixon out of the White House. We saw it simultaneously on TV and through our office window. It was a fascinating site and time historically.
AO/Beck: One of the things that really struck me when I read your book was a note on page 51, which stated that back in 1973 some folks were already considering that the 90 dB safety level should perhaps have been set at 85 dB. The amazing thing to me was the cost of changing from a 90 dB level to an 85 dB level, in 1973 dollars, was stated as 31 billion dollars - almost 30 years ago!
Lipscomb: Yes, that came out in the summer of 1975. The head of the Office of Noise and Abatement at that time was Al Meyer. I had the pleasure of working with him that summer and that information came from the economic reports that were released that year. In response to the enormous cost in dollars and resources to convert to a quieter noise standard, the OSHA administration decided to attack this on two levels. First, they decided to allow HPDs (hearing protection devices) as a final solution if the average time-weighted exposure didn't exceed 100 dB. Additionally, they stated that if the noise was over 100 dB, engineering controls had to be implemented to reduce the TWA (time weighted average) to less than 100 dB, assuming it was economically and technically feasible.
AO/Beck: On a related issue...what is your thought as to the current NRRs (noise reduction ratios) and how to make them less confusing?
Lipscomb: The NRRs are indeed confusing and it would be great if there was a straight-forward solution. However, NRR attempts to take a very difficult and complicated question and apply a simple solution. You know, sometimes a beautiful theory can be covered up by an ugly fact. Lots of people don't understand why you can't just subtract the NRR from the noise level and simply assume the final SPL is the difference. In fact, currently, to use the NRRs, the government recommends we have to subtract 7 dB from the NRR, to account for the transfer from the 'C' weighting to the 'A' weighting, and then cut the result in half. For instance, if the NRR is 29 dB, you subtract 7 dB, leaving 22 dB, and then you cut that in half, so the final NRR is 11 dB.
AO/Beck: Do you have any recommendations on how to improve the NRR system?
Lipscomb: Not really. I bascially don't believe in the NRR system and I don't know of an efficient way to fix it. Basically, you can have two HPDs with the same NRR and they can provide very different attenuation based on the spectrum of the noise itself. The NRRs are not spectrum specific, and that's a part of the problem. One HPD may be great for low frequency noise attenuation, but may be less effective in a high frequency environment, and the converse may be true also. Nonetheless, the problem can be solved by custom selection of HPDs. About 20 years ago I wrote a simple BASIC computer program that reviewed all of the available HPDs, and they would be sorted through and selected based on the noise characteristics including both the spectral and the amplitude characteristics of the noise the worker is exposed to. So bascially, I think we can indeed find efficient HPDs for many noisy environments, but it has to be accomplished on a one-by-one basis. I know it sounds terrifically expensive to do this, but after the set-up and the initiation of the program, it would be cost effective in the long run.
AO/Beck: Do you think the NIOSH (National Institute for Occupational Safety and Health) recommendations will ever be adopted?
Lipscomb: The NIOSH regulations are more stringent than the current regulations. I will tell you that I certainly hope the NIOSH regulations are eventually adopted, but there is a tremendous movement against it. The industries, the Chambers of Commerce and the manufacturers are opposed to more stringent controls. However, in the long run, they would save millions and perhaps billions of dollars by reducing lawsuits and claims and awards to the injured workers by adopting the more stringent criteria.
AO/Beck: Any plans for a new edition of the book (Hearing Conservation in Industry, Schools and the Military. Published by Singular Publishing)?
Lipscomb: Well, at this time, the federal laws have not changed since the book was first introduced. So I haven't planned on revising the book. However, if the laws change, I will come out with a new version. Nonetheless, I am writing a new book, titled 'Investigative Audiology', which will be a sister book to 'Forensic Audiology'. The new book will be published through Lawyers and Judges Publishing in Tuscon, and I think it'll be useful for those of us involved with legal matters, like you and me, and for attorneys too.
I anticipate the new book should come out in about a year.
AO/Beck: Before I let you go, can you spend a few minutes addressing the issue of 'Flag Frequencies' and the interpretation of damage to the ear?
Lipscomb: Yes, I'd be happy to. Years ago we did some research on experimental animals at the University of Tennessee. Basically we found that although the animals had hearing loss at 3K, 4K and 6K -- the Flag Frequencies -- the hair cell loss was across the cochlea, not just at the Flag Frequencies. So this tells us that when a worker has hearing loss at the Flag Frequencies, the damage is across the cochlea, these people indeed have a physical injury. When you add a little background noise to conversational speech, the worker with the Flag Frequency injury falls apart, regarding speech-in-noise word recognition, and I believe that is due to losing cochlear reserve. We'll have more on this topic in an upcoming article for Audiology Online, hopefully in the near future.
AO/Beck: Keep me posted on the new book. I'd love to read it and I'll be honored to interview you regarding the new book and it's content when it's available. In the meantime, thanks so much for your time and expertise this evening. As always, I enjoyed listening and learning from your experiences and thoughts on hearing conservation and noise issues.
Lipscomb: Thank you too Doug, it's been a lot of fun.
Lipscomb: Doing fine thank you. Thanks for the opportunity.
AO/Beck: My pleasure. Let's start with a little about your history. When did you get your Ph.D.?
Lipscomb: I earned my Ph.D. at the University of Washington in Seattle in 1966. Prior to that I worked at the University of Tennessee back in the days when their Speech and Hearing Clinic was actually a private entitiy, funded in part by the state. I was in Tennessee for some 20 years, but my roots in Washington are rather deep. Additionally, I am a lecturer for the University of Florida Au.D. distance education program and I've done a few recorded classes for them.
AO/Beck: Actually, I was one of the students in the second class at the University of Florida Au.D. program. I viewed and studied those videos and we used your book as the class text (Hearing Conservation in Industry, Schools and the Military. Singular Publishing). I am one of those students that tends to write in books and highlight important passages. Resultantly, the whole book is yellow and pink. I learned a lot, but my copy of the book has no resale value in the used book stores!
Lipscomb: That's kind of you to say.
AO/Beck: How did you get interested in Hearing Conservation and legal issues related to audition?
Lipscomb: The first time I dealt with issues relating to high levels of sound was probably about 1965. At that time we had gone to the YMCA to go swimming and as we gathered in the lobby of the YMCA. I heard this horrible noise eminating from the gymnasium. When someone opened the door to enter the gym, the noise nearly knocked us over. Of course it was rock'n'roll, and that got me very interested in the effects of loud noise on the human ear. Prior to that event, I never thought much about it. So that was actually the beginning of my career. Then, when I was working on my Ph.D., noise was the area I became very interested in. Shortly after that, I was asked to investigate a community noise problem where a small iron works company became a large iron works company. One of the residents of that community, who happened to be an attorney, found it distressing to have noise coming from the plant 24 hours a day and 7 days a week and he asked me to look into that. So I got involved based on opportunities which actually presented themselves to me. Another incident which happened at the beginning of my career involved an attorney friend of mine who was representing a fellow who was accused of pulling in front of a speeding police car. The police officer was actually paralyzed from the waist down as a result of the accident. As we examined the parameters, it turned out that the fellow had pulled out with the green light and the issue became why didn't he react to the siren? So we reconstructed the scene with attention to issues like...
Could he indeed hear the siren? Was the siren sufficiently loud and of the right pitch? Did the fellow have the hearing acuity to hear the siren? And on and on, so there were many fascinating questions and as a result, the investigation became very intense and highly thought provoking.
AO/Beck: These incidents were all before the Walsh-Healy Act?
Lipscomb: Yes, these cases were in the mid-1960s. The Walsh-Healy Public Contracts Act was passed in 1969. The Walsh-Healy was the first comprehensive, federally mandated hearing conservation act backed by federal law. As you know, the Walsh-Healy Act initially only impacted some ten-thousand firms that were doing business with the federal government. That regulation became the basis of the 1972, so called Occupational Safety and Health Act (OSHA). In fact, the Walsh-Healy Act was inserted into that word-for-word. I think most people are familiar with OSHA, but the history may be a little unknown. By the way, OSHA does not stand for Our Savior Has Arrived! Of course the OSHA act applied to just about every employer and employee, so it had a far greater impact. So getting back to the original question, I was interested in noise because it was topical and news worthy while I was finishing my studies.
AO/Beck: What about your involvement with the Environmental Protection Agency (EPA)? Can you tell me a little about that?
Lipscomb: In 1973 or so, I was essentially 'on loan' from the University of Tennessee to the EPA Office of Noise Abatement and Control, for a summer exchange program. There, I had the opportunity to observe the generation of federal regulations in response to the Noise Control Act of 1972. While I was there, I made some terrific friendships which I still hold dear today. I had the opportunity to review and prepare documents with Dix Ward, Alice Suter, Art Taylor and Simone Yaniv. The five of us were charged with the preparation of the 1973 Criteria Document, which was prepared by the Office of Noise Abatement and Control, which summarized pretty much what was known about noise at the time. The next year, 1974, we prepared the so-called Levels Document, which was the EPA document that indicated the requisite sound pressure levels, consistent with health and safety for workers with a 'reasonable margin of safety'. The EPA got a bit of a 'bad rap' because some folks were saying that if 'everyone' was truly going to be protected, and if there was to be an additional margin of safety, nobody should be exposed to a lifetime Leq of greater than 70 dB, which is of course, not realistic. So the EPA and the OSHA regulations had about the longest gestation period of any regulations you can imagine. I think it was eleven years until the final regulations came out on March 8, 1983, which defined step-by-step what a Hearing Conservation Program should consist of.
AO/Beck: In this modern age of home computers and word processing excellence, it's hard to imagine a bunch of people sitting around a type-writer trying to agree on wording. You guys must've used a lot of white out!
Lipscomb: It's an amazing history because back then, the secretaries were so poorly trained, and they had such poor equipment, that we often typed things ourselves. Although I can type quickly - it's not very accurate! So to get a neat and clean document out took a great deal of effort, revision and retyping.
AO/Beck: And to further complicate things, this was during the Nixon era and there were lots of political and social things going on in and around Washington DC.
Lipscomb: Funny you should mention that. We had an office that was in Crystal City in Arlington. So we actually did look out of the window from our office and we could see the helicopter lift off of the White House lawn when it lifted Nixon out of the White House. We saw it simultaneously on TV and through our office window. It was a fascinating site and time historically.
AO/Beck: One of the things that really struck me when I read your book was a note on page 51, which stated that back in 1973 some folks were already considering that the 90 dB safety level should perhaps have been set at 85 dB. The amazing thing to me was the cost of changing from a 90 dB level to an 85 dB level, in 1973 dollars, was stated as 31 billion dollars - almost 30 years ago!
Lipscomb: Yes, that came out in the summer of 1975. The head of the Office of Noise and Abatement at that time was Al Meyer. I had the pleasure of working with him that summer and that information came from the economic reports that were released that year. In response to the enormous cost in dollars and resources to convert to a quieter noise standard, the OSHA administration decided to attack this on two levels. First, they decided to allow HPDs (hearing protection devices) as a final solution if the average time-weighted exposure didn't exceed 100 dB. Additionally, they stated that if the noise was over 100 dB, engineering controls had to be implemented to reduce the TWA (time weighted average) to less than 100 dB, assuming it was economically and technically feasible.
AO/Beck: On a related issue...what is your thought as to the current NRRs (noise reduction ratios) and how to make them less confusing?
Lipscomb: The NRRs are indeed confusing and it would be great if there was a straight-forward solution. However, NRR attempts to take a very difficult and complicated question and apply a simple solution. You know, sometimes a beautiful theory can be covered up by an ugly fact. Lots of people don't understand why you can't just subtract the NRR from the noise level and simply assume the final SPL is the difference. In fact, currently, to use the NRRs, the government recommends we have to subtract 7 dB from the NRR, to account for the transfer from the 'C' weighting to the 'A' weighting, and then cut the result in half. For instance, if the NRR is 29 dB, you subtract 7 dB, leaving 22 dB, and then you cut that in half, so the final NRR is 11 dB.
AO/Beck: Do you have any recommendations on how to improve the NRR system?
Lipscomb: Not really. I bascially don't believe in the NRR system and I don't know of an efficient way to fix it. Basically, you can have two HPDs with the same NRR and they can provide very different attenuation based on the spectrum of the noise itself. The NRRs are not spectrum specific, and that's a part of the problem. One HPD may be great for low frequency noise attenuation, but may be less effective in a high frequency environment, and the converse may be true also. Nonetheless, the problem can be solved by custom selection of HPDs. About 20 years ago I wrote a simple BASIC computer program that reviewed all of the available HPDs, and they would be sorted through and selected based on the noise characteristics including both the spectral and the amplitude characteristics of the noise the worker is exposed to. So bascially, I think we can indeed find efficient HPDs for many noisy environments, but it has to be accomplished on a one-by-one basis. I know it sounds terrifically expensive to do this, but after the set-up and the initiation of the program, it would be cost effective in the long run.
AO/Beck: Do you think the NIOSH (National Institute for Occupational Safety and Health) recommendations will ever be adopted?
Lipscomb: The NIOSH regulations are more stringent than the current regulations. I will tell you that I certainly hope the NIOSH regulations are eventually adopted, but there is a tremendous movement against it. The industries, the Chambers of Commerce and the manufacturers are opposed to more stringent controls. However, in the long run, they would save millions and perhaps billions of dollars by reducing lawsuits and claims and awards to the injured workers by adopting the more stringent criteria.
AO/Beck: Any plans for a new edition of the book (Hearing Conservation in Industry, Schools and the Military. Published by Singular Publishing)?
Lipscomb: Well, at this time, the federal laws have not changed since the book was first introduced. So I haven't planned on revising the book. However, if the laws change, I will come out with a new version. Nonetheless, I am writing a new book, titled 'Investigative Audiology', which will be a sister book to 'Forensic Audiology'. The new book will be published through Lawyers and Judges Publishing in Tuscon, and I think it'll be useful for those of us involved with legal matters, like you and me, and for attorneys too.
I anticipate the new book should come out in about a year.
AO/Beck: Before I let you go, can you spend a few minutes addressing the issue of 'Flag Frequencies' and the interpretation of damage to the ear?
Lipscomb: Yes, I'd be happy to. Years ago we did some research on experimental animals at the University of Tennessee. Basically we found that although the animals had hearing loss at 3K, 4K and 6K -- the Flag Frequencies -- the hair cell loss was across the cochlea, not just at the Flag Frequencies. So this tells us that when a worker has hearing loss at the Flag Frequencies, the damage is across the cochlea, these people indeed have a physical injury. When you add a little background noise to conversational speech, the worker with the Flag Frequency injury falls apart, regarding speech-in-noise word recognition, and I believe that is due to losing cochlear reserve. We'll have more on this topic in an upcoming article for Audiology Online, hopefully in the near future.
AO/Beck: Keep me posted on the new book. I'd love to read it and I'll be honored to interview you regarding the new book and it's content when it's available. In the meantime, thanks so much for your time and expertise this evening. As always, I enjoyed listening and learning from your experiences and thoughts on hearing conservation and noise issues.
Lipscomb: Thank you too Doug, it's been a lot of fun.
