Study type: Epidemiological study (observational study)

Auditory changes in mobile users: is evidence forthcoming? epidem.

Published in: Otolaryngol Head Neck Surg 2011; 144 (4): 581-585

Aim of study (acc. to author)

A study was conducted in India to assess the possible changes in hearing function due to chronic exposure to GSM and CDMA mobile phones.

Further details

All participants were taken up for several audiologic investigations including pure-tone audiometry, speech discrimination score, speech reception threshold, impedance audiometry, distortion product otoacoustic emissions (DPOAE), auditory brainstem response (ABR) and middle latency response tests.
Chronic use was defined as using a mobile phone for more than 1 year.

Endpoint/type of risk estimation

Type of risk estimation:

Exposure

Assessment

Exposure groups

Group Description
Reference group 1 nonusers of mobile phones: controls
Group 2 GSM users
Group 3 CDMA users
Group 4 GSM users, cumulative use: < 3 years
Group 5 GSM users, cumulative use: > 3 years
Group 6 CDMA users, cumulative use: < 3 years
Group 7 CDMA users, cumulative use: > 3 years

Population

Study size

Type Value
Participants 183
Other:

63 participants used GSM mobile phones, 62 participants used CDMA mobile phones, 58 participants had never used a mobile phone and served as controls

Statistical analysis method:

Conclusion (acc. to author)

GSM and CDMA mobile phone users were found to be at a significantly higher risk of having distortion product otoacoustic emissions (DPOAE) absent as compared with controls. They were found to have higher speech frequency thresholds and lower Na and Pa amplitudes of the middle latency response. Increased changes in the auditory parameters were observed in participants who used their mobile phones more than 3 years compared to persons who used their mobile phone less than 3 years. The damage done was bilateral, with the quantum of damage being the same for both GSM and CDMA.
The authors conclude that long-term and intensive GSM and CDMA mobile phone use might cause damage to cochlea as well as the auditory cortex.

Study funded by

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