Hearing Loss from Mobile Phone Use

Hearing Loss from Mobile Phone Use Discussion Mobile phones have become a part of modern life style. There has been rapid boom in the number of mobile phones in the recent decade. This rapid worldwide expansion of mobile telephones raises questions regarding possible effects of the emitted radiofrequencies on the health of the consumers. The electromagnetic waves can affect the human health ranging from increase the blood pressure, cause memory loss and induce migraines, hearing impairment to even cancer can also occur. Of all the anatomical structures, the ear is in the closest proximity to the mobile phones, hence most potential organ system to be damaged by the electromagnetic waves emitted from the mobile phones. Pure tone audiometry is a key hearing test for assessment of hearing threshold of the individual. It determines the degree of hearing loss and also type and configuration of hearing loss. Pure tone audiometry uses both air and bone conduction audiometry, the type of loss can be identified by the air-bone gap. In our study, while comparing the results of pure tone audiometry in controls (n=60) and total cases (n=60), it was found that in control group 51 individuals had normal hearing threshold, 08 had mild hearing loss and 01 had moderate hearing loss. Of the total cases, 39 had normal hearing threshold, 19 had mild hearing loss and 2 had moderate hearing loss. No individual in the cases or control group had severe or profound hearing loss. Chi square test with yates correction was applied for statistical analysis of the data, and difference was found to be significant (p value0.05). While comparing the results of distorted product otoacoustic emission (DPOAE) in controls (n=60) and cases Group A (n=30), it was found that in cases group A, 19 individuals passed the test and 11 individuals failed the DPOAE test. Chi square test was applied for statistical analysis of the data, and results were not found to be significant (p value>0.05). On comparing the results of distorted product otoacoustic emission (DPOAE) in controls (n=60) and cases Group B (n=30), it was found that in cases group B, 15 individuals passed the test and 15 individuals failed the DPOAE test. Chi square test was applied for statistical analysis of the data, and results were not found to be significant (p value>0.05). The European project EMFnEAR, was done to assess the harmful effects of short term electromagnetic waves emitted from UTMS mobile device over the outer hair cells. Functioning of outer hair cells was assessed by DPOAE. They concluded that short term exposure to EMFs of mobile phones does not cause measurable immediate effects on the human auditory system. Renzo R et al also conducted a similar study to assess the short term effects of mobile phone use on ear, assessed by transient evoked otoacoustic emissions and brainstem evoked audiometry response. The study parameters were similar to our study but they studied the short term effects of EMFs in contrast to our study where we tried to find the effects of long term exposure. They did not find any change in the auditory functions, before and after the short exposure to electromagnetic radiations. Ozturan et al assessed transient evoked OAE and distorted product OAE in adults exposed to 10 min telephone call using GSM mobile phones. The tests were done before and after the exposure. They concluded that otoacoustic emissions did not change after the electromagnetic waves exposure. Bamiou DE et al also reported that there was no change in the transient evoked otoacoustic emission, due to electromagnetic waves of mobile phones. S Bhagat et al, studied the effects of chronic exposure to EMF emitted from mobile phone on inner ear by using distorted product otoacoustic emissions. Individuals using mobile phones for more than 4 years were studied. It was concluded that long-term and frequent exposure to EMFs from mobile phone does not cause damage to outer hair cells of cochlea. P. Karthikeyan et al did a study on hundred students who were mobile phone users. They were divided into two groups of more than and less than two hours of mobile usage. DPAOE was done and compared to controls. Significant change in DPOAE was seen in cases, more so in group with more than two hours of cell phone usage. Alsanosi AA et al did a study to assess the immediate consequences of 60 minutes exposure to mobile phones on hearing function by determining changes in distortion product otoacoustic emission (DPOAE) and hearing threshold levels (HTLs). They concluded that sixty minutes of close exposure to electromagnetic fields emitted by a mobile phone had an immediate effect on HTL assessed by pure-tone audiogram and inner ear (assessed by DPOAE) in young human subjects. While in our study, on comparing DPOAE, we did not find any significant difference between the total cases and controls. On comparing the each sub group of cases to controls, no statistically significant difference was noted. This is in concurrence with most of the studies done in India and abroad. Though, P. Karthikeyan and Alsanosi have shown different results from those observed in our study. Though a lot of research publications are available in favour of and against the results observed in our study, but in all these studies studied the effects of electromagnetic frequencies of mobile phones on functioning of outer hair cells, but no criteria was taken as standard for comparison as different duration (in years) of exposure, different hours per day of use, and acute effect v/s chronic effects. The major limitation of epidemiological studies addressing the health effects of mobile phone use is related to exposure assessment. Also, other factors were not taken in account like exposure to noise, which is known to cause damage to outer hair cells much before any change in pure tone audiometry is seen (Anjali Desai et al, 1999) (RJ Salvi ea at, 2000). So, with all these factors nothing can be said with much certainty. Further research is needed to establish the effect of EMF on outer hair cells. The present scientific evidences are insufficient to support the belief that there will be no ill effects on human health and the present safety standards are enough to protect users from ill effects, if any. This present situation of scientific uncertainty calls for the requirement of both precautionary measures and further research. Ill effects of mobile phone use on health might be of the field of interest for future research. We conclude from our study that: mobile telephones should be used for short periods only, only for essential purposes, and unnecessary long conversation over mobile phones should be avoided.