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

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Health risks from exposure to noise from personal music players3.9.2.2. Cardiovascular and other physiological effectsTwelve studies found some association between increased blood pressure and noiseinducedhearing loss (Pyykkö et al. 1981, Lang et al. 1986, Pyykkö et al. 1987, Verbeeket al. 1987, Milković-Kraus 1990, Talbott et al. 1990, Solerte et al. 1991, Starck et al.1999, Souto Souza et al. 2001, Toppila et al. 2001, Narlawar et al. 2006, Ni et al. 2007).In contrast eleven other studies did not find such an association (Lees RE, Roberts JH.1979, Willson et al. 1979, Ickes and Nader 1982, Kent et al. 1986, Gold et al. 1989,Kontosić et al. 1990, Tarter and Robins 1990, Hirai et al. 1991, Garcia and Garcia 1993,Zamarro et al. 1992, Barberino 1995). Overall both groups of positive and negativestudies are quite comparable in sampling and other methodologies. It must be notedhowever that the positive findings report moderate average differences sometimesrestricted within studies to sub-groups such as only the more exposed or the youngers orthose who also smoked showing altered blood pressure. The question of causalityremains open, the cardiovascular differences having been simply observed asconcommittant. Two studies (Tomanek 1975, Dengerink et al. 1982) producedexperimental temporary threshold shifts which were found related with alteredcardiovascular parameters, however physiological processes underlying temporary andpermanent threshold shifts are known to be notably different. A recent extensive reviewby Babisch (2006) dealing specifically with exposure to road or aircraft noise on bloodpressure, hypertension and ischaemic heart disease concludes that there is no clearevidence of increased blood pressure. Whereas for aircraft noise (but not road noiseexposure) most recent studies (Babisch 2006) indicate some significant relationship,finally concerning ischeamic heart disease more recent studies also suggest a trendtowards increased risk as compared with previous studies.3.9.3. ConclusionsExposing oneself to music from a PMP is a matter of a personal choice of leisure activity.Harmful lasting and irreversible non-auditory effects of excessive listening to PMP can beexpected in three areas: (1) Cardiovascular effects, (2) cognition and (3) distraction andmasking effects. Cardiovascular effects, in particular increases in blood pressure, build upand accumulate over time, when there is not enough silent time in between noiseexposures to recover. However, we do not have sufficient evidence to state that musicfrom PMPs constitutes a risk for hypertension and ischaemic heart disease in children andyoung adults.Effects on cognition (memory and learning) of excessive sound exposure has been shownfrom acute noise exposure and from chronic noise exposure. Noise exposure for 15 minto 66 dB(A), and for aircraft noise down to 55 dB(A) has been shown to cause impairedlearning and memory of a text. We have no study stating that the same is true also formusic, but we also have no reason to believe that music should be substantially lessharmful to cognition that aircraft noise, road traffic noise or speech noise. Thus, listeningto music from PMP while at the same time trying to read a text and learn from it, willhamper memory and learning. This learning impairment has been shown at fairly short(15 min) exposure times and at sound levels that are moderate (55-65 dB(A)).Prolonged exposure to chronic aircraft noise has been shown to impair cognition inchildren, but there is also one indication that children may recover from the noiseinduced cognitive deficit when the noise exposure stops.We do not as yet have a sufficient scientific basis to assume that excessive voluntaryPMP-listening leads to lasting and irreversible cognitive and attention deficits after thecessation of the noise.58
Health risks from exposure to noise from personal music players4. OPINIONThe SCENIHR was asked to assess, in the light of current scientific data and knowledge:1. Whether the exposure to noise 19 from devices like personal music players andmobile phones with this function, at levels corresponding to current permissiblenoise emissions may cause quantifiable health risks, in particular hearing lossand/or hearing impairment to the user, and to specify the relevant outcomes;2. In case health risks are identified, the SCENIHR is asked:a. to identify the level of noise emission safeguarding the health of citizens,taking into account the intensity, length and number of exposures to usersof personal music players and mobile phones with the same function andb. to identify priority issues for further research.BackgroundThe increase in unit sales of portable music players (PMP) including MP3 playbackfunction has been phenomenal since their introduction in the EU around four years ago.Estimated units sales range between 184-246 million for all portable audio devices andrange between 124-165 million for MP3 players. There was a marked increase in overallportable audio devices sales in 2005 and sales were maintained in the following yearswith more than 50 million devices being sold per year by 2007. Mobile phones are soldby similar numbers of units every year. However, at present the availability of the MP3functionality is not widespread in these handsets (maybe ten percent) while theirfrequency of use remains as yet unknown.Although the data for the portable audio market are accessible, there are nodemographics easily available on these sales, nor any information on how many devicesan individual may buy over a given time period, how long they last before beingdiscarded and how long and in what situations they are used. Thus, it is hard to estimatethe proportion of the population that has access to portable audio or to MP3 players, andhow many use them on daily basis. However, it may be estimated on rather conservativeway that in EU the number of users of devices like personal music players and mobilephones with this function, are in tens of millions daily.The digital formats of sound recording and reproduction currently available (e.g. MP3)make it possible to reach high levels of sound output with virtually no distortion, thatcould possibly cause a risk to human hearing originating from the inappropriate use ofportable music players.As shown by many studies, noise-induced hearing loss (NIHL) is a function of sound leveland duration of exposure. The fundamental unit of noise exposure measurement is A-weighted decibel [dB(A)]. This unit corresponds well with the physiological sensitivity ofhuman ear and it has been generally adopted in scientific literature.Noise at Work Regulations (Directive 2003/10/EC, came into force in 2006) establish aminimal action level of hearing protection to the limit of 80 dB(A) for an 8 hour workingday (or 40 hour working week) assuming that below this level the risk to hearing isnegligible. The exposure to sound at the level exceeding 80 dB(A) is considered a risk if itcontinues at that level for 8 hours a day, five days a week for tens of years. The 8-hourequivalent level (L equ, 8h ) is a widely used measure for the risk of hearing damage inindustry. On the basis of equal energy, level and time of exposure may be traded with19Please note that throughout this opinion, the term ‘noise’ is used consistently in the context of all disease andmalfunction patterns, while the word ‘sound’ is used consequently to clarify that the concern is thevoluntary listener of personal music players and not the observer of the listening situation. For details seeparagraph 3.3.159
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