|Year : 2017 | Volume
| Issue : 1 | Page : 1-6
The effect of mobile phone usage on hearing in adult population
Punnoose Philip, Satheesh Kumar Bhandary, Rajeswary Aroor, Vadish Bhat, Deepika Pratap
Department of ENT, K S Hegde Medical Academy, Deralakatte, Mangalore, Karnataka, India
|Date of Web Publication||6-Feb-2017|
Satheesh Kumar Bhandary
Dean, Professor of ENT, K. S. Hegde Medical Academy, Nitte University, Mangalore - 575 018, Karnataka
Source of Support: None, Conflict of Interest: None
Background and Objective: The widespread use of mobile phones in recent years, especially among young people, has given rise to concerns about the potential influences of its electromagnetic fields (EMFs) on human health. The present study is conducted to investigate the adverse effects of mobile phone usage on auditory functions and to study the pattern of hearing threshold in mobile phone users. Materials and Methods: The study group consisted of 150 healthy volunteers between the age group of 21 and 45 years. They were divided into three groups; Group A consists of fifty participants who were using mobile phones for more than 1 h per day, Group B consists of fifty participants who were using mobile phones for <1 h per day, (both groups for a minimum period of 4 years), and Group C consists of fifty participants who did not use mobile phones or very occasional users (<1 h per week), being taken as control group. All participants underwent tympanometry and distortion product otoacoustic emission (DPOAE) tests and the results were compared among groups. Results: It is found that the prevalence of sensorineural hearing loss was seen in 10% participants of Group A and only 2% participants of Group B, but none among Group C had hearing loss, but this was statistically insignificant. The changes in DPOAEs were studied among groups and found significant difference between Group A (>1 h/day) and Group C (control group). Conclusion: The present study revealed that prolonged and frequent exposure to EMFs from mobile phone use can cause damage to the outer hair cells, especially in the basal turn of the cochlea, which can be detected by otoacoustic emission test and can subsequently lead to high frequency hearing loss.
Keywords: Electromagnetic radiations, mobile phone, radiofrequency waves
|How to cite this article:|
Philip P, Bhandary SK, Aroor R, Bhat V, Pratap D. The effect of mobile phone usage on hearing in adult population. Indian J Otol 2017;23:1-6
| Introduction|| |
India is the world's fastest growing mobile phone market after China. Being the most common gadget in India, an estimated 1009.46 million Indian population (November 2015) uses mobile phone. India is also the second largest telecommunication network in the world after China in terms of number of wireless connections.
The widespread use of mobile phones in recent years, especially among young people, has given rise to concerns about the potential effects of its use on human health.
The present study is designed to investigate the possible effects of long-term exposure to electromagnetic fields (EMFs) from mobile phones on the inner ear.
| Materials and Methods|| |
This is a cross-sectional study among mobile phone users and limited users between the age group of 21 and 45 years conducted in the Department of Otorhinolaryngology and Head and Neck Surgery and the Department of Audiology, Speech, and Language Pathology in our hospital over a period of 1½ years from January 2014 to June 2015.
The study group consisted of 150 healthy volunteers between the age group of 21 and 45 years and they were divided into three groups; Group A consists of fifty participants who were using mobile phones for more than 1 h per day, Group B consists of fifty participants who were using mobile phones for <1 h per day, (both groups for a minimum period of 4 years), and Group C consists of fifty participants who did not use mobile phones or very occasional users (<1 h per week), being taken as the control group.
Those participants with ear diseases or history of decreased hearing due to any cause; participants with history of diabetes, consumption of ototoxic drugs, recent ear/nose/throat infection, psychological problems; and those participants who are carrying out social or work activities in environments exposed to acoustic contamination (use of firearms, explosives, industrial machinery, pneumatic drills, pneumatic hammers, sirens) are excluded from this study.
All the candidates were subjected to a detailed history taking with special emphasis on duration, pattern, and years of mobile phone use. All candidates were subjected to pure tone audiometry (PTA) (0.25–8 kHz) separately in both the ears, and distortion product otoacoustic emission (DPOAE) test was conducted in all participants.
The collected information was summarized by descriptive statistics. To evaluate groups with respect to PTA and DPOAE, Fischer's exact test, Kruskal–Wallis test, and Chi-square value were used.
Level of significance was considered in P value. The analysis was performed using Statistical Package for the Social Sciences software version 22.0 (IBM, India).
| Results|| |
Among 150 participants, 79 (52.7%) are males and 71 (47.3%) are females. In our study, majority among Group A are males and Group C are females. The age of participants varied from 21 to 45 years. The mean age of the participants in Group A is 26 years, in Group B is 31 years, and in control group is 37 years.
Mean years of exposure in Group A is 5.92 years while that of Group B is 6.26 and Group C is 2.93 years.
In this study, in Group A: 7 (4.6%) participants had 1–2 h of exposure/day, 31 (20.6%) had 2–3 h/day, 12 (8.0%) had 3–4 h of exposure to mobile phone per day. In Group B: all 50 (33.3%) participants had 0–1 h of exposure/day. In Group C: 3 (2.0%) participants did not expose to mobile phones, whereas 47 (31.3%) participants had exposed only 0–1 h/week.
Types of exposure noted in our groups are either intermittent or continuous.
Intermittent exposure is noted in 127 (84.6%) participants, continuous exposure is noted in 20 (13.3%) participants, and 3 (2%) participants did not expose to mobile phones.
In this study, 56 (37.3%) participants are bilateral users, 45 (30.0%) participants preferred using on the right side, and 46 (30.6%) participants preferred using on the left side.
Blocked sensation (13.3%), burning sensation (9.3%), tinnitus (8.0%), hearing loss (6.6%) are the main symptoms in the study group at the time of presentation. Only one participant had a complaint of blocked sensation among control group. All the symptoms are statistically significant (P < 0.05) between Group A and C.
Sensorineural hearing loss (SNHL) of 5 dB is seen in 5 (10%) participants in Group A and only 1 (2%) participants in Group B, but none among Group C had hearing loss [Table 1].
In Group A, 6% and 4% of cases had minimal SNHL (5–10 dB loss) in the right and left ears, respectively; while in Group B, 2% had SNHL in the right ear only. However, none among Group C had SNHL. SNHL in the PTA is not statistically significant between all three groups as the P > 0.05 [Table 1].
In our study group, among participants who used mobile phones for 0–1 h daily, 5 dB hearing loss was noted in 1 participant, whereas 5 dB hearing loss was noted in 4 participants among those using mobile phones for 2–3 h daily and 5 dB hearing loss is noted in only 1 participant among those using mobile phones for 3–4 h daily [Table 2].
In Group A, out of 15 continuous mobile phone users, 3 had SNHL and out of 35 intermittent users none had hearing loss, this is statistically significant with a p-value of 0.2. In Group B out of 5 continuous users none had hearing loss whereas out of 45 intermittent users 1 had hearing loss. In Group C 47 subjects were intermittent mobile phone users and none among them had hearing loss.
In Group B, out of 5 continuous users, none had hearing loss, whereas out of 45 intermittent users, 1 had hearing loss.
In Group C, 47 participants were intermittent mobile phone users, and none among them had hearing loss [Table 3].
In Group A, out of 15 and 35 continuous and intermittent mobile phone users, only 1 each had SNHL; this is statistically insignificant with a P - 0.51. In Groups B and C, none of the patients had hearing loss in the left ear [Table 4].
Otoacoustic emission test results
When average of total frequencies (0.5–8 KHz) was considered, there is no statistical significance found between groups [Table 5].
Different frequencies of otoacoustic emission – Right ear
In this study, there is not much difference noted between the groups in low and mid frequencies; however, when high frequency is considered, 22 participants in Group A had absent otoacoustic emissions (OAEs) compared to 17 participants in Group B and 8 participants in Group C, which is statistically significant between Groups A and B with a P - 0.008 [Table 6] and [Figure 1].
|Table 6: Average of otoacoustic emission in different frequencies-Right ear|
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|Figure 1: Average of otoacoustic emission in different frequencies – Right ear.|
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Different frequencies of otoacoustic emission – Left ear
Similarly, in low and mid frequency, there is no significant difference between groups in the left ear; however, in high frequency, 21 participants in Group A, 16 participants in Group B, and 9 participants in Group C had absent OAE, which is statistically significant with a P - 0.03 [Table 7] and [Figure 2].
|Table 7: Average of otoacoustic emission in different frequencies-Left ear|
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|Figure 2: Average of otoacoustic emission in different frequencies – Left ear.|
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| Discussion|| |
Mobile telephones have been available since 1983; the widespread use of mobile phones has been going sky-high over the past decade and now its use is an essential part of business, commerce, and society. This has given rise to the concern about potential influences of EMF emitted by mobile phones on health.
There are two types of electromagnetic (EM) radiations: ionizing radiation and nonionizing radiation. The ionizing radiation is composed of energy levels high enough to strip electrons from atoms and molecules. Hence, exposure to ionizing radiation can cause serious biological damage. Nonionizing radiation is the radiation that is insufficient to cause ionization. Radiofrequency radiation includes bands used in radio and television, mobile phones, and microwave are in the nonionizing EM radiation.
The exposure to mobile phones can be calculated and quantified by means of amount of radio frequency energy absorbed by a unit mass of object, which is expressed as the specific absorption rate (SAR) with units of W/kg.
Mobile phones are usually held close to the outer ear, approximate distance of 3 cm to the inner ear, which provides a natural low attenuation route through the external auditory canal and middle ear for EM radiation to reach the inner ear leading to relatively high SAR deposition, and potentially damage the peripheral auditory structures as compared to the rest of the body. The SAR depends not only by the types of the mobile phones but also from the manufacturer, model of the phone, the distance between a mobile phone and its tower.
Digital handsets (time division multiple access, code division multiple access, and global system for mobile communications) expose the user's ear to an SAR almost always below 2 W/kg.
International Commission on Nonionizing Radiation Protection (ICNIRP) is a body of independent scientific experts established with an aim to provide information and insight into the potential health hazards of exposure to nonionizing radiation. According to the ICNIRP guidelines for limiting exposure to time-varying electric, magnetic, and EMFs, the maximum SAR value has been set at 2 W/kg for mobile phones. It means in countries such as India where these guidelines are adopted, the SAR of every mobile phone sold in the country should be <2 W/kg.
Keeping in view the adverse effects of mobile phones, the present study was designed to investigate the effects of mobile phone usage on hearing.
In Group A, we had more number of youngsters who are exposed to mobile phones for more than 1 h/day with a mean age of 26 years; in Group B, all participants are intermediate users with a mean age of 31 years; and in Group C, most of them are older participants compared to other groups with a mean age of 37 years.
In our study, we have found that mobile phone ownership and usage are more common among college students and text messaging was reported to be more popular than talking.
Hearing loss was present in both males and females in this study; no significant relationship was found between hearing loss and each gender.
In our study, blocked sensation (13.3%), followed by burning sensation (9.3%), tinnitus (8.0%), and hearing loss (6.6%) are the main symptoms in the study group at the time of presentation. Only one participant had a complaint of blocked sensation in the control group.
These findings were almost similar to the study conducted by Hegde et al.; the overall mean percentage for presenting complaints in their study group was blocked sensation (15%), tinnitus (10%), and hearing loss (3.3%). Sahoo and Sebastian  in their study showed that 5% of participants had complaints of tinnitus, 4% had vertigo, and 10% and 8% had ear discomfort and fullness in the ear, respectively.
In our study, 13.3% of participants who have been using mobile phone for 2–3 h daily had SNHL and 8.33% of those who have been using it for 3–4 h/day had SNHL. This indicates that the minimal hearing loss (5 dB) noted in the study group depends not only on hours of exposure but also on the type of exposure, i.e., intermittent or continuous, and noted that continuous exposure is more associated with hearing loss.
This relates to the study done by Garcia Callejo et al., who conducted an audiometric evaluation in the beginning of mobile phone use in 323 healthy volunteers. These volunteers were followed up 3 years later and noticed an increase in hearing threshold between 1 and 5 dB HL more than in controls in speech tones.
A similar study conducted by Ramya et al. reported the relationship between the duration of usage of mobile phones per day and the change in auditory threshold using PTA in fifty participants and found significant increases in hearing thresholds at all frequencies.
In our study, we observed that five participants in Group A and only 1 participant in Group B had minimal SNHL and hearing loss was unilateral among them, whereas none of the participants had bilateral hearing loss.
Distortion product otoacoustic emissions
OAEs were first discovered by Dr. David Kemp in 1978; they are known to be highly specific for the intensity and spectrum characteristics of the stimulus as it is for the individual's response. For this reason, OAE test would be useful in eliciting any effect on outer hair cells function when exposed to EM radiation from mobile phones. OAE recordings are a sensitive and reliable method to assess in vivo cochlear functionality; the presence of OAE is an indicator of normal contractile outer hair cells. Two commonly measured types of OAE are DPOAEs and transiently evoked OAE.
Very limited data are available in the literature regarding interaction between mobile phone and inner ear using OAE.
In our study, we used DPOAE test to study the effects of mobile usage in cochlear function which are undetectable by PTA.
When average of total frequencies (0.5–8 KHz) are taken into consideration, we observed that out of all participants in Group A, OAE is absent in 6 (12.0%) participants in the right ear and 5 (10.0%) participants in the left ear, and 7 (14.0%) participants in both right and left ear in Groups B and C. This was statistically not significant between groups.
However, when high frequencies (5 + 6 +7 KHz) are considered, we have found a significant difference in the absence of OAE between Groups A and C, i.e., 22 (44%) participants in Group A had absent OAE compared to only 8 (16%) participants in Group C in the right ear with a P - 0.008. Similarly, in Group A, 21 (42.0%) participants had absent OAE in the left ear compared to 9 (18.0%) participants in Group C, with a significant P - 0.03.
The results obtained from our studies are also favoring the conclusions provided by Panda et al. that increase the duration of use as well as use of more than 1 h/day can lead to outer hair cells damage at high frequencies in OAE.
Oktay and Dasdag  found a higher degree of hearing loss associated with long-term exposure to EMFs generated by cellular phones on comparing with the controls in their study.
Kerekhanjanarong et al. in their study reported that those participants who use mobile phones for more than 60 min/day had worse hearing threshold in the dominant ear compared to nondominant ear.
Similarly, a very recent study by Sahoo and Sebastian  observed prevalence of SNHL in the habitual mobile phone users, which was found to be directly correlated to the duration of usage. Ramya et al. in their study showed associated increase in hearing threshold in mobile phone users with longer duration of use.
Significant absence of OAE in high frequency suggests that the most common area to be affected due to radiofrequency waves from mobile phones is the basal turn of cochlea. Hearing loss in the higher frequencies can affect speech. Once the hearing loss is significant, the only option is to use hearing aid devices.
We also noted that hearing loss increases with increase in duration of use.
An individual using a mobile phone for any purpose is in one way or the other exposed to either of these factors, that is, if he is using the mobile in hand while talking, then EM radiation has its effect, and if he uses a hands-free device, sound produces its effect.
| Conclusion|| |
The present study revealed that prolonged and frequent exposure to EMFs from mobile phone use can cause damage to the outer hair cells, especially in the basal turn of the cochlea, which can be detected by OAE test and can subsequently lead to high frequency hearing loss. DPOAE test is very sensitive audiological test to detect early cochlear damage due to EM radiations. We feel that the younger generation needs to be educated about the adverse effects of prolonged use of mobile phones. However, we recommend a long-term follow-up and further study in this field.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7]