Panda NK, Jain R, Bakshi J, Munjal S. (2010). Audiologic disturbances in long-term mobile phone users. J Otolaryngol Head Neck Surg. 39(1):5-11.
Introduction and Objective
Biological electrical activities, including those in the central nervous system, may be vulnerable to interference from electromagnetic field (EMF) radiation. The objective of this study was to assess potential effects of chronic exposure to EMF emitted from GSM mobile phones on hearing function at the level of the inner ear and central auditory pathway. To the author’s knowledge, this was the first study of the effects of EMF exposure from mobile phones on hearing function at this level.
This retrospective cross-sectional study included 112 adult subjects (18-45 years of age) who used GSM mobile phones for more than one year, and 50 control subjects who never used GSM mobile phones. Persons with a history of ear pathology, any disease that might affect hearing, head trauma or prolonged noise exposure were excluded. The mobile phone users were categorized into 3 categories based on years of use: 1-2 years (37 subjects), 2-4 years (39 subjects), and >4 years (36 subjects). Each category of years of use was divided into two groups based on daily use of a mobile phone: less than 60 minutes per day or more than 60 minutes per day. Both mobile phone users and controls were divided into two age groups: ≤30 years and >30 years. The battery of examinations included pure-tone audiometry (PTA), speech discrimination score, speech reception threshold, impedance audiometry, distortion product otoacoustic emission (DPOAE), auditory brainstem response (ABR) audiometry, and middle latency response (MLR) tests.
There were no significant differences between mobile phone users and controls in age and sex distribution, or in any of the tested audiologic parameters. None of the subjects had hearing loss in the range of speech frequencies. However, some trends were observed within the users. There was a marginally significant (p=0.05) increase in the proportion of abnormal high-frequency pure-tone threshold (HFPTA) in the mobile phone using ear of mobile phone users over 30 years of age compared to the younger users. There was no such a difference for the non- mobile phone -using ear. Also, users who talked on a mobile phone for more than 60 minutes per day had higher HFTPA in their mobile phone-using ear than users who talked for less than 60 minutes (P=0.05). Subjects with mobile phone use duration of more than 4 years had significantly higher HFTPA in their mobile phone-using ear compared to those with mobile phone use of less than 2 years; no significant differences in HFPTA depending on the duration of mobile phone use were observed in the non-mobile phone-using ear. Similar trends by age (≤30; >30 years) and daily talk time (<60 minutes; >60 minutes a day) were observed for distortion product otoacoustic emission abnormalities, though the trend for talk time was not statistically significant. No significant trends were observed for auditory brainstem response or middle latency response except for a significant difference in auditory brainstem response abnormalities between the users who had complaints while using mobile phone (e.g. ear warmth, ear fullness and tinnitus) and users who had no complaints.
Interpretation and Conclusion
The results suggest that cochlear and inner ear damage may occur in long-term users of GSM mobile phones. Risk factors for audiologic disturbances may include older age, excessive daily use, long total duration of use, and the presence of ear discomfort during mobile phone use. The authors note that their results should be interpreted with caution. Further studies based on larger populations would be required to reach definitive conclusions.