Maribeth DiSalvo, Tricia Deatharidge, Timothy Phoenix, K. M. Hutchinson and Helaine Alessio

1. Hear the Music: Effects of Cardiovascular Fitness on Hearing Sensitivity and Otoacoustic Emissions Among Musicians and Nonmusicians Maribeth DiSalvo, Tricia Deatharidge, Timothy Phoenix, K. M. Hutchinson and Helaine Alessio Miami University, Oxford, Ohio

2. Abstract Deafness or hearing impairment resulting from prolonged exposure to loud noise is most frequently associated with industrial workplaces, airports etc. Studies have shown that up to 52 % of classical musicians and up to 30 % of rock or pop musicians suffer from music-induced hearing loss (MIHL). Recent studies, however, have revisited some prior ways of thinking about sensory changes due to noise, and have uncovered variables other than time and duration of exposure, that play a significant role in hearing changes. In this study, cardiovascular (CV) health and hearing acuity were measured in 30 musicians and 35 nonmusicians, aged 19-24 years. Pure tone hearing results showed that the high CV fitness had better hearing than low CV subjects. Otoacoustic emissions demonstrated similar patterns. The fitness-hearing relation appears to be specifically related to CV fitness among both groups.

3. Introduction It can result from the booming drums or the blaring guitar amplifiers of a hard-rock group. But it can also result from the violin or the piccolo flute of a symphony orchestra. For a musician whose livelihood depends on rehearsing and playing music 4-8 hours a day, the danger of a hearing impairment is always present. It is hardly surprising that music can cause damage while on the job. The sound pressure of a large concert orchestra may reach 112 dB – of amplified rock bands even up to 130 dB, far more than that accepted in an industrial environment. Reasons for reduced hearing acuity over time include compromised blood circulation through the inner ear. Variations in cochlea blood flow may affect the availability of oxygen and glucose, which is more rapidly metabolized during sound stimulation. If a person has a compromised circulation it is possible that blood flow through the cochlea may also be reduced.

4. Introduction cont. There is also evidence that chronic exercise may have a protective role in hearing conservation. Researchers reported improved pure tone and temporary threshold shifts in healthy but low-average fit young adults who improved their VO2 peak following eight weeks of twice-weekly aerobic exercise performed at 70% of maximum oxygen consumption. On the other hand, older adults (>50 years) who were healthy but low-average fitness, did not improve either hearing acuity nor VO2 peak following eight weeks of twice-weekly aerobic exercise performed at 70% of maximum oxygen consumption. The purpose of this study was to determine if hearing acuity among a group of musicians and nonmusicians was influenced by cardiovascular health in subjects aged 18-26 years. Repeated exposure to high levels of sound can cause hearing loss, particularly in the higher frequency ranges. Therefore hearing thresholds were measured up to 16 kHz.

5. Methods Subjects were 65 volunteers, 29 females and 36 males (mean age 22 years) with 30 musicians and 35 nonmusicians. No one reported smoking. None reported a history of any significant noise exposure, other than their music performances. All subjects were found to determine normal hearing sensitivity (thresholds 25 dB HL or above from 1000 to 6000 Hz). Baseline pure tone frequency thresholds were determined on a GSI 33 audiometer using insert earphones. Closed dynamic HAD 200 Audiometric Headphones, were used to test extended high frequency (EHF) hearing levels. Distortion Product Otoacoustic Emissions (OAE) were measured using a Madsen Celeste OAE instrument from 2000 to 4000 Hz at a f1/f2 ratio of 1.22 and levels of 65/55.

6. Methods cont. VO2 peak was determined using a submaximum graded exercise test on a Monark Bicycle ergometer or using a questionnaire designed to estimate VO2 max. Heart rate and blood pressure were measured during the graded exercise tests. No test had to be terminated due to subjects’ report of angina, or any other abnormal exercise response. Analysis of variance (ANOVA) was used to compare pure tone hearing levels and OAEs between and within the two groups. Pure tone hearing levels are reported at three frequencies: 2 , 3, and 4 kHz and at extended high frequencies between 10 to16kHz. Post-hoc analysis using contrast-comparison tests compared hearing levels among the high and low fitness category groups at three frequencies to determine whether hearing was significantly different on a group by group comparison for each test period. The significant probability level was p< .05.

7. Descriptive Variables of Two Subject Groups

8. Results • No significant difference in the mean DPOAE and high frequency pure-tone levels between and within musicians and non-musicians • No significant difference between VO2 levels of musicians and non-musicians • Significance at .05 alpha level within musicians group concerning signal to noise ratio

9. Discussion • Marked trend in EHF thresholds of musicians compared to nonmusicians • As frequency increased, greater differences in thresholds were found between groups in favor of the musicians • Both groups within normative data ranges • No statistically significant differences in thresholds between different musicians

10. Discussion • Predicted VO2 maximal values were not significantly different between the two groups. • DPOAE amplitudes across the frequencies were not statistically significant. • Signal to noise significance noted as a trend due to small sample size • Results possibly due to effects of everyday exposure to leisure noise within the control group.

11. Summary Reasons for this cardiovascular health-hearing association are unclear, but it has been speculated that relative to persons with low VO2max, circulation of blood in persons with above average VO2max, may be enhanced. Circulation of the blood may be improved by less resistance to blood flow, higher oxygenation of blood, or greater sensitivity and ability of tissues to receive blood.

12. References Ahmed, H.O., Dennis, J.H., Badran, O., Ismail, M., Ballal, S.G., Ashoor, A., & Jerwood, D. (2001). High-frequency (10-18kHz) hearing thresholds: reliability, and effects of age and occupational noise exposure. Occup Med, 51, 4, 245-258. Chasin, Marshall (1996). Musicians and the prevention of hearing loss. San Diego: Singular Publishing. Hall, J.W. & Santucci, M. (1995). Protecting the professional ear: conservation strategies and devices. The Hearing Journal, 48, 3, 37-45. Harrell, R.W. (2001). Pure tone evaluation. In J.Katz (Ed.), Handbook of Clinical Audiology, (pp. 71-87). Baltimore, MD: Lippincott, Williams & Wilkins. Henderson, D., McFadden, S.L., Liu, C.C., Hight, N., & Zheng, X.Y. (1999). Role of antioxidants in protection from impulse noise. In Henderson, D., Salvi, R., Quaranta, A., McFadden, S., Burkard, R., (Eds), Ototoxicity: Basic Science and Clinical Application (pp. 368-380). New York: New York Academy of Sciences. Hutchinson, K.M., Alessio, H.M., Hoppes, S., Gruner, A., Sanker, A., Ambrose, J. & Rudge, S.J. (2000). Effects of cardiovascular fitness and muscle strength on hearing sensitivity. Journal of Strength and Conditioning Research, 14, 3, 302-309. Manson, J., Alessio, H., Cristell, M., & Hutchinson, K.M. (1994). Does cardiovascular health mediate hearing ability? Medicine and Science in Sports and Exercise, 26, 7, 866-871. Stelmachowicz, P.G., Beauchaine, A.K., Kalberer, A. & Jesteadt, W. (1989). Normative thresholds in the 8-to-20kHz range as a function of age. J. Acoust. Soc. Am., 86, 4, 1384-1391.