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

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