1 Music, sound, or noise? Sonic culture in Ghana and its public health implications Florian Carl, University of Cape Coast Eric D. Otchere, University of Cape Coast Abstract The sonic culture of any place is always locally specific. Yet, beyond cultural differences, there are more general health implications of sound production and exposure, particularly where high sound levels with potentially damaging effects to the inner ear are concerned. The purpose of this study was to investigate further into the socio-cultural, psychological, and physiological dimensions of sound production, exposure and perception in a Ghanaian context. Specifically, we aimed to examine how people who regularly deal with electronic sound equipment evaluate sound stimuli in different contexts. We used three different instruments: first, we measured ambient noise levels at live music events and during band rehearsals; we then conducted air conduction threshold tests to assess participants’ status of hearing; and, as a complementary instrument, we used a structured questionnaire to assess levels of sound exposure as well as participants’ evaluation of environmental noise. Our results revealed that amateur and professional musicians are indeed a high risk group with regard to potential hearing damage. We therefore concluded that awareness campaigns and counter-measures with regard to sound/noise pollution need to be designed more specifically for different target groups to address their respective needs. Keywords: sonic culture; sound exposure; noise; hearing loss; public health Introduction Noise is increasingly recognized as an environmental problem and a public health issue. In the recent past, various noise-related issues have made the news in Ghana. For example, in September 2013, ten churches in the Ga West Municipality were reported to have been issued with summons to be prosecuted for noise nuisance Digitized by UCC LIB 2 (Ghana News Agency, 2013). Also, the Daily Graphic's issue of February 15, 2013, reported the demolition of a church by the Accra Metropolitan Assembly (AMA) for making excessive noise (Wireko, 2013). However, despite a number of recent campaigns by government agencies to raise public awareness about the negative health effects of noise pollution as well as isolated actions against offenders in the Greater Accra Region, the enforcement of existing laws seems to remain a major challenge. In an article dubbed "Ghana, a nation of noise makers", which appeared in the Ghana Herald, Adorsu-Djentu (2013) expresses his frustration over daily noise nuisances by describing the mélange of sounds that surround the Ghanaian city dweller day in, day out: the muezzin's call at dawn, the cacophonous assembly of street noises, the singing and preaching through megaphones by self-appointed evangelists, the shouting of street sellers, the piercing sounds of PA systems used at lorry stations, loud amplified music played in drinking spots and from moving vehicles to advertise various products – the list goes on. It seems that in order to deal with noise pollution in Ghana a more profound cultural change is needed. While there are a number of studies investigating environmental noise and its mostly non-auditory psychosocial effects, studies examining the more direct auditory effects of noise exposure in the Ghanaian context are still scarce. Particularly the effects of exposure to loud music have, so far, not attracted the attention of researchers in Ghana. Targeting professional and lay musicians within the Cape Coast metropolitan area, the objective of this study was therefore to find out how people regularly exposed to loud music evaluate and behave towards noise. By examining the audiograms particularly of people regularly dealing with electronic sound equipment, the study endeavoured to ascertain whether there are connections between listening behaviour, sound exposure, and people’s status of hearing. Towards this end, we conducted listening tests and administered a structured questionnaire, comparing in our analysis the audiograms of people with their self-reported exposure and behaviour towards amplified sound. Specifically, this study aimed to: • Evaluate how people perceive environmental sounds. • Measure sound levels at live music events and during band rehearsals. • Find out about professional and lay musicians' behaviour towards amplified sound and high noise levels. Digitized by UCC LIB 3 • Assess the status of hearing of professionals and laypeople regularly working with electronic sound equipment. Review of Literature The health effects of noise on the human body, which include both physical and psychosocial responses, have been well documented (e.g., Godlee, 1992; Guéguen et al., 2008; Halononen et al., 2012; Lercher, Evans, Meis & Kofler, 2002; Westman & Walters, 1981; McBride, 2010; van Kempen et al., 2002). They range from risk of hearing loss, hypertension, indigestion, heart burn, ulcers, heart disease, mental illness, fatigue, damages to the nervous system, stress, insomnia, reduced efficiency at work places and general decrease of performance. In understanding these noise- related health effects, it is important to bear in mind the basic evolutionary function of the auditory system, which is actually an alarm system constantly monitoring the sonic environment for potential dangers and threats. This warning function, in human beings as in other mammals, regulates fundamental auditory responses to sound stimuli and includes an orientation reflex as well as a startle reflex, both of which then initiate a defensive response that eventually sets off a so-called fight-or-flight reaction (Westman & Walters, 1981). Studies have demonstrated that the physiological effects of this defensive mechanism, which translate into a stress response that might or might not be experienced as actual stress by the individual, also occur under real working conditions, particularly in noise-intensive industries, where patients showed heightened risk of gastric ulcer (McBride, 2010; Westman & Walters, 1981). A stress response, including increased blood pressure, acceleration of pulse rate, pupillary dilation, as well as reduction in salivary and gastric secretions and slowing of digestive processes, could be measured in patients under laboratory conditions after 25 minutes exposure to noise levels of 85 decibels (Westman & Walters, 1981). As a warning mechanism crucial to the survival of early man, our auditory system is on alert even when we sleep. A study conducted in Finland indicated that insomnia associated with night-time traffic noise occurs at levels from 50 decibels and above (Halonen et al., 2012). Other studies suggest that even noise levels at 45 dB and Digitized by UCC LIB 4 below can interfere with sleep patterns (Godlee, 1992). Summarising the various health effects of noise, Godlee (1992) writes: Noise damages hearing. Environmental noise probably contributes little to the overall risk of hearing loss, except where loud music is concerned. Low levels of noise in the environment can, however, damage health in the wider sense of wellbeing. Noise also contributes to the dehumanising effect of our increasingly urban society (p. 113). One of the major challenges in dealing with noise pollution is the difficulty in defining what noise actually is. One person's music might, as we all know, well be another person's noise, and vice versa. The Oxford English Dictionary refers to 'noise' as an "unpleasant", "unwanted", or any "loud sound". In electronics and engineering, the term is also used to denote disturbances in signalling systems. We all know, however, that loud music, which would qualify as loud sound, can, under certain circumstances, also be experienced as pleasurable. Physically speaking, noise is sometimes defined by the absence of periodic vibrations, an understanding of noise as 'unmusical sound' which is still used in technical terms like 'white noise' or 'pink noise' (Schafer, 1994, p. 182). It is, however, important to note that even in the realm of music not all sounds are strictly musical in this narrow sense, as any music, to varying degrees, also includes sounds with non-periodic vibrations and no discernible pitch (see Figure 1). In defining noise, law-makers have largely followed two opposed approaches, a qualitative and a quantitative one. Since the qualitative approach, defining noise as 'unpleasant' or 'unwanted' sound, is highly subjective – unpleasant for or unwanted by whom? –, in noise abatement legislations around the world, it is the quantitative approach that has gained greater acceptance. Many countries, however, still combine both a qualitative and a quantitative approach in their attempts to tackle the legal implications of noise pollution (Schafer, 1994, pp. 189-197). In Ghana, it is the Environmental Protection Agency (EPA) that, as per the EPA Act 490 of 1994, is mandated to prescribe standards and guidelines relating to environmental pollution, including noise. According to the Local Government Act 462, Section 296(7), of 1993, it is an offence, punishable by law, for noise to be made in any town. The EPA, following international standards, has adopted a quantitative approach to noise Digitized by UCC LIB 5 pollution, and set maximum permissible noise levels measured in decibel for variously defined urban areas (see Table 1). In a number of studies conducted in Ghana, researchers have investigated ambient noise levels and their physical as well as psychosocial effects. A study carried out by Armah et al. (2010) investigated ambient noise levels emanating from religious activities in residential neighbourhoods in the Cape Coast metropolis. The results of this study show that most of the locations' recorded noise levels were above the maximum permissible limits set by the EPA and that the levels of noise exposure generally correlated with levels of annoyance of residents. Another study of ambient noise levels in the main commercial area of Cape Coast, Kotokuraba, showed that sound levels at all 10 measuring points exceeded the upper limits prescribed by the EPA by values of 1-15 dBA (Essadoh & Armah, 2011). In a similar study, the authors report that noise levels in halls of residence at University of Cape Coast, particularly in the mixed-gender halls, exceeded the permissible limits set by the EPA (Essandoh, Armah, Afrifa & Pappoe, 2011). And, finally, Omari, De-Veer and Amfo-Otu (2013) assessed the level of industrial noise and associated health effects on workers within the Tema Industrial Area. Their results indicate that more than half of the workers who participated in the study were suffering from occupational noise-induced hearing loss and reported difficulties to hear words clearly in normal conversations. All of these studies point to the need for further investigations into the problematic of sound exposure and its associated health effects, to help direct the attention of people towards the dangers of loud music and noise. It is a common sight to see students these days with in-ear phones listening to music at high volume levels for many hours of the day, oblivious of the possible long-term consequences. As McBride (2010) opines, "exposure to music, both live through music systems and the use of personal stereos, may be hazardous for the few that listen for long periods at excessive levels" (p. 11). We need to remind ourselves that noise-induced hearing loss is irreversible, as the hair cells of the inner ear do not regenerate like, for instance, skin cells do. Materials and Methods Sample Group: The participants in this study were made up of 21 people purposively selected because of their involvement in musical activities that exposed them to Digitized by UCC LIB 6 amplified sound for many hours (M = 15 hrs.) weekly. Two groups of were involved: 1) Professional musicians who sang or played various musical instruments in a band and rehearsed for at least two hours daily and; 2) lay musicians who sang in a choir and rehearsed for about six hours a week accompanied by amplified synthesizers. The age range of the participants was between 20 and 54 with the majority (81%) falling within the range between 20 to 29 years. In all, there were four females and seventeen males who participated in the study. The number of years of participants' involvement in musical activities ranged from a minimum of 4 years to a maximum of 35 years (M = 15 years). Materials: For the measurement of noise levels at live music events and during band rehearsals, a professional calibrated Sound Level Meter (SLM) with a measuring range of 40-130 dB and an accuracy of ±3.5 dB (at 1 kHz and 94 dB) was used. Measurements were taken at various distances from the sound sources and, in some cases, ambient noise levels were measured, using an A-weighted decibel scale (dBA). For the testing of air conduction thresholds of hearing of participants, sound files based on the ISO 389-7:2005 international standard using third octave band warble tones at frequencies ranging from 250 Hz to 8 kHz on an ascending loudness scale from -5 dBHL to 80 dBHL (hearing level) were used. ISO 389-7:2005 is recommended by the British Society of Audiology and does not rely on a particular type of headphone. In this study, we used professional closed studio headphones (AKG K-66) with a frequency range of 18 Hz to 20 kHz. The listening tests took place in a sound-proof recording studio and the sound equipment was calibrated at 1 kHz and 50 dB. Methods: The analysis of the data of air conduction thresholds was based on the guidelines formulated by Coles, Lutman and Buffin (2000) for the diagnosis of noise- induced hearing loss for medicolegal purposes. In addition to hearing tests, data for this study was also acquired through the use of a structured questionnaire. The use of the questionnaire as a complementary instrument to the hearing test was informed by the results of other similar studies. McBride (2010) indicates that "the history of noise exposure is elicited by taking a careful occupational history, noting 'significant' noisy jobs, tasks undertaken doing jobs and noisy equipment used. From this the likely noise exposure levels experienced can be defined" (p. 9). The questionnaire helped us Digitized by UCC LIB 7 to gather information on the occupational and other relevant history of the participants. Besides basic biographical information, the questions on the questionnaire were meant to solicit information that would help in the interpretation of the emerging audiograms from the hearing tests. We were interested in how the participants evaluated their own sonic environment and whether they were aware of any possible auditory effects of regular exposure to amplified sound. The results of the questionnaire and the hearing tests were analysed using Microsoft Excel and Statistical Package for Social Sciences (SPSS) software. To complement both self- reported sound exposure length and intensity and the data analysed in the audiograms, measurements of noise levels were conducted at various programmes, live music events within Cape Coast and during band rehearsals. Discussion of Results Asked about the sounds that were experienced as most disturbing, respondents mentioned, in descending order, traffic and vehicular sounds (car horns, sirens, speed ramps), human voices (market women, jama groups, quarrelling), machines (generators, PA systems, speaker feedbacks, spinners, television), religious sounds (church bells, singing, clapping, mosque calls), music played by others (apart from spinners or in a religious event), as well as animal sounds (crickets, crowing cock). Among the sounds experienced as pleasant by participants were, first of all, music (self-selected and played at desired levels), and, second, natural sounds (birds, streams, sea waves, crying baby). Below, we grouped these sounds variously experienced as disturbing or pleasant by the frequencies with which they were mentioned into five broader categories, namely traffic noise/machine sounds, music (amplified as well as non- amplified), human-made sounds, religious sounds, and sounds of nature (see figure 2). What we can see in the chart is that traffic noise and machine sounds, human-made noise, as well as religious sounds such as congregational worship, church bells, and calls for prayer were almost unanimously experienced as disturbing by our respondents. Nature and animal sounds, on the other hand, were predominantly experienced as pleasant. The category that was evaluated most ambivalently by participants was music, which was frequently mentioned as both disturbing and pleasant. Music was experienced as pleasant when it was self-selected and played at Digitized by UCC LIB 8 desired levels, which could be low as well as high. Music was perceived as disturbance by participants when the element of control over the sound source was lacking, i.e. when it was played by others at undesired levels, times and locations. Apart from one person, all other respondents found problems with the sound levels they were exposed to at public events and places where amplified music was being played, such as social gatherings, in restaurants and bars, or in churches. With the exception of one person, again, who reported that the sounds could be either too high or too low, the major problem with sound reported by participants was that the levels were too high. Overall, 52% of the participants said they sometimes found problems with sound levels, and at least a third (33%) reported to have found problems with sound levels often (figure 3). Coping strategies with too high sound levels at public events were to either avoid such events altogether or, where this was not possible, to choose a sitting position away from or behind the speakers. Overall 86.4% of participants considered the sound level as a factor in choosing a place to spend time, generally indicating a preference for quieter places. In connection with the perceived problems of sound levels, it is, however, interesting to note that, again, a major criterion in participants' evaluation was control over the sound source and the question whether exposure was self-determined or not. Thus, while most participants said they had a problem with sound levels at public events, the majority did not have a problem with sound levels during rehearsals or performances in which they were themselves involved, despite the fact that the actual levels that we measured were in both cases similar and the levels during rehearsals even exceeded those at public events (table 2). As far as the status of hearing is concerned, ninety-five percent (95%) of the participants in this study said they had experienced tinnitus before, the majority (62%) more than once, 9% only once, and almost a quarter (24%) often (figure 4). Although participants were generally aware of the dangers of exposure to high sound levels, the majority (81.8%) never used ear protection kits and those who had tried ear protection before said that they had only used it briefly, but did not feel comfortable with it. In relation to age, there was no statistically significant difference in the hearing thresholds of participants in this study (table 3). When asked about their status of hearing, most participants (57%) indicated that they did not have difficulties to understand other people during a normal conversation. A third of the respondents (33%) said they sometimes experienced Digitized by UCC LIB 9 difficulties in hearing others during conversations, and 10% reported to have had such problems often (figure 5). Generally speaking, these percentages correspond with the results of the listening tests we conducted, where 57% had normal hearing, 24% showed signs of mild noise-induced hearing loss, and 19% moderate noise-induced hearing loss (figure 6). In two cases participants who showed signs of mild or moderate hearing loss reported to not have had problems of hearing during conversations, and in one case, a participant with a normal audiogram reported to sometimes have experienced difficulties in hearing during conversations. The perceived status of hearing does, therefore, not necessarily coincide with one's actual status of hearing. While the audiograms of the majority of participants (57%) were within the normal range, at least 19% of these still showed at least slightly raised hearing levels (values of 20 dBHL) at 4 kHz (figure 7). Audiograms with a typical peak around 4 kHz (“noise notch”) are usually interpreted as an indication of mild noise-induced hearing loss at hearing levels between 25-35 dBHL and of moderate noise-induced hearing loss for values of 40-55 dBHL (figure 8), which was the case for 24% and 19% of participants respectively. Among the participants of the study we had one case where the audiogram turned out to be particularly irregular, with a mild to moderate asymmetrical hearing loss that only affected the right ear. Strangely enough, the participant perceived all sounds during the listening test with the left ear, even those that were played on the right side (figure 9). The results of this audiogram indicate a blockage of the right ear that might have been caused by the penetration with a cotton swab or ear bud. This could have led to a congestion of the outer ear and the hearing loss might therefore only be temporary, not due to a damage of the middle or inner ear. In any case, we advised the person to see an ear specialist. According to studies examining the auditory effects of occupational noise (e.g. McBride, 2010: Omari et al., 2013), exposure to sound levels of 85 dbA and above over prolonged periods of time can cause noise-induced hearing loss. Our data clearly indicates that the status of hearing of professional as well as lay musicians who were regularly exposed to high levels of amplified sound – on an average 15 hours per week at levels often reaching 90-100 dbA – had been negatively affected. Overall, 43% of the participants showed indication of irreversible noise-induced hearing loss at mild or moderate levels. Given the fact that the effects of noise exposure are Digitized by UCC LIB 10 cumulative and, thus, increase over time, an additional 19% of participants showed signs of beginning noise-induced hearing loss with hearing thresholds of 20 dBHL at 4 kHz and can therefore be considered a high risk group. This adds up to a total of 62% of participants whose hearing had been negatively and irreversibly affected by noise exposure, which is particularly worrisome when one considers the overall relatively young average age of participants. Conclusion and Recommendations To conclude, the results of this study clearly show that both professional and lay musicians are a high risk group in terms of potential hearing loss. While study participants were aware of the potentially harmful effects of exposure to loud music, this knowledge did generally not result in behavioural changes that would, in the long run, prevent damage to the ears. Since hearing loss is a rather slow, gradual and cumulative process, professional and lay musicians seem to underestimate the negative effects of exposure to loud music. A problem with this might be unconcern or carelessness as well as the lack of availability of professional ear protection kits, which need to meet certain requirements to be viable for musicians, such as an undistorted frequency range while reducing the overall sound level. To aid public awareness campaigns, we recommend that further studies of this nature be conducted that include larger sample groups. We also recommend that future studies should include the testing of bone conduction thresholds to get more precise data on people's status of hearing. Awareness campaigns about noise as a health risk need to be designed for specific target groups, as exposure and behaviour towards sound differs, depending on the occupation and leisure preferences of people. The status of hearing should regularly be tested in schools and parents and pupils be educated about the health effects of noise and sound exposure, so that potential threats can be detected at an early age and protective measures be taken. With regard to noise pollution more generally, a more rigorous and proactive role of law enforcement agencies is certainly in order. However, beyond law-enforcement there is, at the same time, the need to work towards a more fundamental change of the sonic culture and people's perception and behaviour towards sound in Ghana, so that in the mid- to long-term we will be able to create a healthier sonic environment for everybody. Digitized by UCC LIB 11 References Adorsu-Djentuh, F. Y. (2013, December 26). Ghana, A Nation of Noise Makers. Ghana Herald. Retrieved December 26, 2013, from http://www.ghanaherald.com/ghana-a-nation-of-noise-makers/ Armah, F. A., Odoi, J. O., Yawson, D. O., Yengoh, G. T., Afrifa, E. K. A., & Pappoe, A. N. M. (2010). Mapping of Noise Risk Zones Derived from Religious Activities and Perceptions in Residential Neighbourhoods in the Cape Coast Metropolis, Ghana. Environmental Hazards, 9(4), 358–368. Coles, R. R. A., Lutman, M. E., & Buffin, J. T. (2000). Guidelines on the Diagnosis of Noise-Induced Hearing Loss for Medicolegal purposes. Clinical Otolaryngology, 25, 264–273. Environmental Protection Agency. (2008). Ambient Noise Level Guidelines on Residential Areas. Accra, Ghana. Essandoh, P. K., & Armah, F. A. (2011). Determination of Ambient Noise Levels in the Main Commercial Area of Cape Coast, Ghana. Research Journal of Environmental and Earth Sciences, 3(6), 637–644. Essandoh, P. K., Armah, F. A., Afrifa, E. K. A., & Pappoe, A. N. M. (2011). Determination of Ambient Noise Levels and Perception of Residents in Halls at the University of Cape Coast, Ghana. Environment and Natural Resources Research, 1(1), 181–188. Ghana News Agency. (2013, September 18). Noisy Churches to be Prosecuted. Ghana Business News. Retrieved December 26, 2013, from http://www.ghanabusinessnews.com/2013/09/18/noisy-churches-to-be- prosecuted/ Godlee, F. (1992). Noise: Breaking the Silence. British Medical Journal, 304(6819), 110–113. Guéguen, N., Jacob, C., Le Guellec, H., Morineau, T., & Lourel, M. (2008). Sound Level of Environmental Music and Drinking Behavior: A Field Experiment With Beer Drinkers. Alcoholism: Clinical and Experimental Research, 32(10), 1795–1798. Halonen, J. I., Vahtera, J., Stansfeld, S., Yli-Tuomi, T., Salo, P., Pentti, J., … Lanki, T. (2012). Associations between Nighttime Traffic Noise and Sleep: The Digitized by UCC LIB 12 Finnish Public Sector Study. Environmental Health Perspectives, 120(10), 1391–1396. Lercher, P., Evans, G. W., Meis, M., & Kofler, W. W. (2002). Ambient Neighbourhood Noise and Children’s Mental Health. Occupational and Environmental Medicine, 59(6), 380–386. McBride, D. (2010). Guideline for Diagnosing Occupational Noise-Induced Hearing Loss, Part 1: Noise Effects and Duration. Dunedin, New Zealand: University of Otago. Retrieved from http://www.acc.co.nz/PRD_EXT_CSMP/groups/external_communications/do cuments/reference_tools/wpc091005.pdf Omari, S., De-Veer, A., & Amfo-Otu, R. (2013). The Silent Killer: An Assessment of Level of Industrial Noise and Associated Health Effects on Workers. International Journal of Basic and Applied Sciences, 2(2), 165–169. Schafer, R. M. (1994). The Soundscape: Our Sonic Environment and the Tuning of the World. Rochester, VT: Destiny Books. Van Kempen, E. E. M. M., Kruize, H., Boshuizen, H. C., Ameling, C. B., Staatsen, B. A. M., & de Hollander, A. E. M. (2002). The Association between Noise Exposure and Blood Pressure and Ischemic Heart Disease: A Meta-Analysis. Environmental Health Perspectives, 110(3), 307–317. Westman, J. C., & Walters, J. R. (1981). Noise and Stress: A Comprehensive Approach. Environmental Health Perspectives, 41, 291–309. Wireko, V. (2013, February 20). Reality Zone: Clamp down on noise making - is it too little too late? Daily Graphic. Retrieved December 26, 2013, from http://graphic.com.gh/archive/features/reality-zone-clamp-down-on-noise- making-is-it-too-little-too-late.html Digitized by UCC LIB 13 Figure 1: 'Pink noise' showing typical non-periodic vibrations (top) as compared to a sound with discernable pitch and periodic vibrations (bottom) Digitized by UCC LIB 14 Table 1: Ambient Noise Level Guidelines of the EPA, Ghana Zone Description of Area of Noise Reception Permissible Noise Level in dBA 0600 - 2200 hrs 2200 - 0600 hrs A Residential areas with negligible or infrequent transportation 55 48 B1 Educational (school) and health (hospital) facilities 55 50 B2 Area with some commercial or light industry 60 55 C1 Area with some light industry, place of entertainment or public assembly and place of worship such as churches and mosques 65 60 C2 Predominantly commercial areas 75 65 D Light industrial areas 70 60 E Predominantly heavy industrial areas 70 70 Source: Environmental Protection Agency, 2008 Digitized by UCC LIB 15 Figure 2: Perception of sounds as disturbing or pleasant Digitized by UCC LIB 16 Figure 3: Perceived problems with sound levels at public events Digitized by UCC LIB 17 Table 2: Sound Levels of Music Measured at Various Events in Cape Coast Description of Event measured sound levels distance range average Live band playing outdoors (Faculty of Arts, UCC, end-of-year party) 5 m 94-103 dBA 100 dBA 10 m 92-99 dBA 95 dBA 25 m 88-98 dBA 92 dBA Live band playing Friday night at Goil Filling Station around 8 p.m. 15 m 82-92 dBA 87 dBA around 9 p.m. 15 m 88-96 dBA 93 dBA around 10 p.m. 15 m 89-97 dBA 95 dBA Congregational singing accompanied by keyboard during 31st- night service ambient 72-93 dBA 87 dBA 10-member band rehearsal, indoors (medium sized room) ambient 95-105 dBA 100 dBA Music played at outdoor sports program, Ankaful prisons park 150 m 54-65 dBA 59 dBA 50 m 51-76 dBA 71 dBA 10 m 72-100 dBA 91 dBA Source: Field Survey (2013-14) Digitized by UCC LIB 18 Figure 4: Experience of tinnitus Digitized by UCC LIB 19 Table 3: ANOVA of hearing threshold of participants in relation to age Sum of Squares df Mean Square F Sig. Left ear at 250 Hz Between Groups 8.097 5 1.619 1.687 .195 Within Groups 15.357 16 .960 Total 23.455 21 Left ear at 500 Hz Between Groups 5.116 5 1.023 .902 .504 Within Groups 18.157 16 1.135 Total 23.273 21 Left ear at 1000 Hz Between Groups 13.034 5 2.607 3.459 .026 Within Groups 12.057 16 .754 Total 25.091 21 Left ear at 2000 Hz Between Groups 11.100 5 2.220 .618 .688 Within Groups 57.490 16 3.593 Total 68.591 21 Left ear at 4000 Hz Between Groups 29.139 5 5.828 .970 .465 Within Groups 96.133 16 6.008 Total 125.273 21 Left ear at 8000 Hz Between Groups 22.116 5 4.423 1.226 .342 Within Groups 57.748 16 3.609 Total 79.864 21 Right ear at 250 Hz Between Groups 8.207 5 1.641 1.155 .373 Within Groups 22.748 16 1.422 Total 30.955 21 Right ear at 500 Hz Between Groups 13.311 5 2.662 2.669 .061 Within Groups 15.962 16 .998 Total 29.273 21 Right ear at 1000 Hz Between Groups 13.534 5 2.707 1.153 .374 Within Groups 37.557 16 2.347 Total 51.091 21 Right ear at 2000 Hz Between Groups 8.462 5 1.692 .419 .829 Within Groups 64.629 16 4.039 Total 73.091 21 Right ear at 4000 Hz Between Groups 43.071 5 8.614 2.214 .104 Within Groups 62.248 16 3.890 Digitized by UCC LIB 20 Total 105.318 21 Right ear at 8000 Hz Between Groups 37.802 5 7.560 3.178 .035 Within Groups 38.062 16 2.379 Total 75.864 21 Source: Field Survey (2013-14) Digitized by UCC LIB 21 Figure 5: Self-reported difficulties in hearing during conversations Digitized by UCC LIB 22 Figure 6: Status of hearing based on listening test Digitized by UCC LIB 23 Figure 7: Audiograms indicating normal hearing (right: 4 kHz slightly raised to 20 dBHL) (red = right ear / blue = left ear) Digitized by UCC LIB 24 Figure 8: Typical audiograms indicating mild (left) and moderate (right) noise- induced hearing loss, including levels and frequencies of speech sounds Digitized by UCC LIB 25 Figure 9: Asymmetrical mild to moderate hearing loss of the right ear Digitized by UCC LIB