Potential health risks of exposure to noise from personal music ...

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Health risks from exposure to noise from personal music playersvenues exposed to more than 90 dB(A) and up to peak levels of 124 dB(A), small butsignificant TTS was observed. In a study by Bray et al. (2004) on 23 dance music diskjockeys three exhibited dip losses of NIHL type in their audiogram and sixteen reportedTTS and tinnitus after job sessions. Among eighty-eight young adults with normalhearing and no tinnitus Rosanowski et al. (2006) indicated about 20% reporting tinnitusafter visiting a disco and about 50% reporting a transient hearing loss. Schmuziger et al.(2006) examined 42 non professional pop/rock musicians exposed for at least five yearsand compared with a control group of 20 non exposed matched subjects, on average asmall but significant hearing loss was found in pop/rock musicians, eleven of themusicians were hypersensitive to loud sounds and seven reported tinnitus. Stormer andStenklev (2007) reviewed seven publications on pop musicians emphasising prevalenceof permanent hearing loss, tinnitus hyperacusis and increased resistance to loud music.Finally Schmuziger et al. (2007) indicate in 16 non professional rock/pop musicians a TTSafter rehearsal of 90 minutes at a mean acoustic level of 103 dB(A), the TTS affectedusual audiometric frequencies while surprisingly very high frequencies were not affected.Meecham and Hume (2001) questioned 545 students attending night clubs and showed asignificant association between attendance at night clubs and duration of post-exposuretinnitus. Non-attendees were significantly less likely to get spontaneous tinnitus.Overall the data concerning NIHL, associated with pop concerts and discotheques,presents some analogies with those presented above for PMPs. The range of acousticlevels of exposure is can go higher, however the duration and number of times ofexposures is smaller. Short term studies clearly demonstrate reversible hearing lossesafter exposures. The studies started about 30 years ago so that rather long-term dataare now available and there is no clear evidence that prevalence of NIHL linked to popconcerts has increased significantly over the last 30 years.3.8.6. Risk associated with classical orchestral musicIn classical orchestras sound levels are on average considerably less than in pop concertsbut in some music pieces may also be quite high for long durations and thus musiciansappear to be also at some risk of NIHL. A few studies only have dealt with assessment ofthis risk. Westmore and Everdsen (1981) found slight hearing losses of the notched NIHLtype in about a third of 68 musicians, acoustic recordings during rehearsals revealedlevels in excess of 90 dB(A) in only 4 hours out of a total of 14 hours. Johnson et al.(1986) tested 60 orchestral musicians in comparison with matched non musicians andthey found no difference in hearing sensitivity even at very high frequencies. In contrastOstri et al. (1989) tested 95 orchestral musicians and found hearing losses in 58% ofthem in the form of a NIHL type notched audiogram. McBride et al. (1992) did not findclear evidence for NIHL in 36 musicians. Assessment of hearing in 62 choir singersindicated some hearing losses mostly at low frequencies in contrast with the usualpattern of NIHL. From audiometric testing of 140 classical orchestral musicians Kahari etal. (2001) did not find clear evidence for NIHL related hearing losses. Laitinen et al.(2003) measured sound levels for a variety of instrument players and playing conditions,during performances individual exposure levels could be 95 dB(A) while at rehearsalslevels could be 100 dB(A).These studies indicate that for classical musicians involved in classical music acousticlevels of exposure exceed occasionally risk thresholds, but there is no undisputableevidence for an associated NIHL.3.8.7. ConclusionsIt seems that the majority of young users of personal listening devices are at low risk fora substantial NIHL.The risk of permanent sensorineural hearing loss arises from repeated, regular dailyexposures to high sound levels.54
Health risks from exposure to noise from personal music playersExcessive acute exposures to PMPs music at maximal or near maximal output volume canproduce reversible hearing impairment (temporary threshold shift) up to 30 dB at 4 kHzin some individuals after short time (one or more hours) of exposure. However, the riskof hearing loss and tinnitus is much smaller compared to pop concerts and discothequesmusic exposures.There are major discrepancies between the results of the studies on permanent NIHL inPMP users. They could arise from different study designs and methodology. Most of thesestudies showed none or only small permanent effect of using PMP on hearing in themajority of users, if short term consequences were assessed with audiometric hearingthreshold. A lack of long-term studies and with using more sensitive hearing outcomes,like for example otoacoustic emissions makes it difficult to conclude whether theexposure to PMP music in teenage may influences hearing in older age.Overall the data concerning NIHL, associated with pop concerts and discotheques,presents some analogies with those presented above for PMPs. The range of acousticlevels of exposure can go higher, however the duration and number of times ofexposures is smaller. Short term studies clearly demonstrate reversible hearing lossesafter exposures.Studies for classical musicians indicate that their level of exposure occasionally exceedrisk threshold, but there is no undisputable evidence for an associated NIHL.3.9. Non-auditory effectsThe non-auditory effects of noise on children and adolescents basically fall into twocategories. (1) At the psychological level, seen as changes in reading, memory,attention, school achievement, and motivation and (2) other effects, mainly those whoshow up at biological or physiological level.3.9.1. Psychological effectsPertaining to the psychological effects on cognition and attention, there is no reportedresearch on noise from PMPs. However there are reliable findings of the noise effectsfrom other noise sources on cognition and attention in children and young adults. Thus,to consider possible outcomes of PMP-use it is worthwhile to briefly summarize relevantresearch, coming mainly from studies of aircraft and road-traffic noise.3.9.1.1. Reading and memoryThe best documented impact of noise on children's performance is research showingnegative effects on reading acquisition. Close to twenty studies have found indications ofnegative relations between chronic noise exposure and delayed reading acquisition inyoung children (Evans and Lepore 1993). There are no contradictory findings and the fewnull results are likely due to methodological problems, such as comparing children acrossschool districts who have different reading curricula (Cohen et al. 1986).There are fewer studies of other cognitive processes and noise among children relative toreading. However, noise effects on memory have been the focus of a handful of studies.The most ubiquitous memory effects occur in chronic noise, particularly when complex,semantic materials are probed (Hygge 2003). Several studies of both chronic (Evans etal. 1995, Haines et al. 2001a, Hygge et al. 2002) and acute noise (Boman 2004, Bomanet al. 2005, Hygge 2003, Hygge et al. 2003) have found adverse impacts of aircraft orroad traffic noise exposure on long term memory for complex, difficult material.Stansfeld et al. (2005) replicated these effects on long term memory for chronic aircraftnoise.In the experimental acute noise studies by Boman (2004), Hygge (2003), Hygge et al.(2003) worse (approx. 15-20 %) long-term learning and memory in children was induced55
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