40 healthy medical students (31 men and 9 women, aged 20 to 30 years) who had been regular mobile phone users for at least 4 years were divided into two groups of 20 based on the duration of their daily mobile phone use: 1) ≤ 1 hour and 2) > 1 hour. The non-phone-using ear served as each subject's control ear.
No significant differences were found between both groups or between the phone-use ear and control ear in subjects in any parameter. None of the subjects reported any subjective symptoms.
The authors conclude that long-term mobile phone usage has no effect on the auditory function of healthy students.