Features
December 31, 1999

Hearing Loss Secondary to Sound Exposure

By Dr. Patrick L. Potter, MD, FRCPC

No studies have been completed with respect to hearing loss in Highland pipers or drummers. Therefore, one can only postulate a possible cause and effect relationship with respect to hearing loss due to years of musical performance. There is, however, anecdotal evidence that suggests such hearing loss occurs. Given the sound intensity during playing of the Highland pipes, particularly during band performance, compared to other orchestral studies, one may assume that there could be a significant effect on hearing. (Ogilvie) A number of pipers have encountered high frequency bearing loss in patterns consistent with hearing loss due to excessive environmental noise. This article will deal with the effect on hearing by sound exposure, in particular, exposure to loud music.

The Highland bagpipe produces sound between the frequencies of 115 hertz (Hz) (bass drone) and 920Hz (high A). Although these are the fundamental frequencies, there are harmonics associated with all musical sounds and the sound energy produced by the Highland bagpipe covers a much broader spectrum of frequencies because of the nature of the harmonies.

Sound levels produced by the Highland pipes can be measured by a small microphone in the ear canal or can be measured in the space surrounding a performer. In the fundamental frequencies, there is fairly high energy production peaking at approximately 93 decibels (dB). Significant sound energy is produced in the higher frequencies going up to 8,000Hz, well outside what we consider our musical range, but still of importance because this is the total sound energy that is being experienced by the ear.

Figure 2 demonstrates the sound frequencies and level of exposure experienced by a violinist, again using the left ear canal, and noting that the strings of the violin are immediately adjacent to the ear. Because of the small distance between the ear and the strings, the sound energy produced on the violin is similar to the pipes, in the intensity experienced by the performer. Sound energy dissipates rapidly the greater distance the observers are away from the point of sound production. Sound intensity levels in the several feet surrounding a solo piper are in the range of 85 to 90dB SPL. Six pipers produce a sound intensity in the range of 95 to 102dB. With the addition of the drum corps, measuring around the circle during a performance, the sound experienced by the players as a whole sometimes exceeds 11OdD.

Playing in confined spaces increases the intensity of sound experienced as this does not allow for dissipation of the sound energy.

Sound energy produced by different pipe bands is likely only to vary 5-1OdB from the levels noted, the major difference being in the number of players.

Although there is anecdotal evidence that there is an association with hearing loss among pipers, there have been no specific studies looking at the frequency of this hearing loss pattern within Highland musicians. When hearing loss occurs due to sound exposure, over an extended period, usually in terms of years, there is a common pattern of hearing loss. Figure 3 demonstrates a normal audiogram in a piper without symptoms. All threshold levels of sound can be appreciated.

Figure 4 shows that hearing loss in the high frequency range for a piper is normally seen due to sound exposure. There is a drop in the threshold at which sound can be appreciated in the higher frequencies after 3,000Hz, This means that a sound has to be 2OdB louder to be heard by this person compared to normal hearing. In this particular case, there is no history of exposure to any other high sound intensities in either work, home or recreational areas. The only high intensity levels have been within pipe bands over the past fifteen years. The hearing deficit was not readily apparent to the player except when in environments in which there was background noise such that conversational speech was difficult to hear.

Temporary threshold loss is one symptom experienced which may be associated with later hearing loss due to sound exposure. After leaving band practice where they have played for an extended period of time in a confined space, band members experience numbness or ringing in the ears and for a few hours after playing, they are unable to hear properly. Studies done on noise exposure in the work environment and in orchestra musicians indicate that temporary threshold hearing loss is a sign that with repeated exposure to such sound levels one might go on to more permanent hearing loss.

Music played at the same sound levels as industrial noise does not result in the same extent of hearing loss. The non-steady state nature of music (i.e. the varying intensity of sound) may reduce the hazard to hearing produced by musical sound. Of 250 professional musicians (not Highland musicians) seen for non-hearing related problems (i.e. people who had no symptomatic hearing loss) 89-percent had some evidence of loss in the typical 3,000 to 6,000Hz region during a screening hearing examination.(Chasin.1992)

Guidelines
Guidelines for conservation of hearing in industry have been published and in gen-eral 9OdBa is the commonly quoted sound exposure threshold for an eight-hour day. 90dBa is a compromise level which has been chosen to protect the hearing of workers for those frequencies necessary for speech (i.e. 500 to 3,000Hz). The National Institute for Occupational Safety and Health suggests that 85dBa exposure would be more realistic in terms of hearing protection. Very commonly in industrial noise levels exceed 9OdBa. Industrial standards of sound intensity versus duration of exposure are shown in Table 1.

Summary:
In summary, a cause and effect relationship between exposure levels above 90dB an hearing loss has been documented in the industrial population. The temporary hearing loss seen related to music appears to be less than that related to the same sound levels if produced by industrial noise. The sound levels experienced in a pipe band with all members performing approaches the upper ranges of what is acceptable, a shown in Table 1.

Although there are no statistics to directly state that there is definite hearing loss related to pipe band performance, there is likely enough information to postulate that this is a potential problem with exposure to such sound levels over a long period. In this regard, the next step would be to look at what is available for hearing protection.

Dr. Patrick Potter is a leading authority in Canada on physical medicine and rehabilitalion, and he is a fellow of the Royal College of Physicians and Surgeons. He is a piper and an original member of the Halifax Police Pipe Band of Nova Scotia.

References
Chasm M. Chong J. “A clinically efficient hearing protection program for musicians.” Med Probl Perform Art 1992,7:4043.
Jerger J, Jerger S. “Temporary threshold shin in rock-and-roll musicians.” J Speech Hearhig 19,0,13:221-224.
Karlsson K, Lundquist PG, Olaussen T. ‘The hearing of symphony orchestra musicians.” Scan Audiol 1983.12:257-264
Ogilvie 0. “Now hear this (if you can).” New Zealand Pipe Bandsman Magazine 1985, p 8 -10.

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