Background and Aim: Transcranial Magnetic Stimulation is a novel technique for inhibition or excitation of brain cortical area. Dichotic listening test is a simple instrument to determine dominant ear and brain hemisphere for processing of verbal stimuli. This study aimed to determine changes in right ear advantage(REA), after applying inhibitory rTMS protocol on left Broca area.

Materials and Methods: In this descriptive - cross-sectional study, we compared the performances of 14 right handed normal adult Persian speakers with normal auditory and no history of psychiatric or neurological disorders. TMS was applied at 1 Hz with 90% motor threshold, for 10 minutes (600 pulses) on left Broca's area. The right ear advantage index was assessed pre and post rTMS using dichotic listening test.

Results: Finding of the present study showed no significant difference on right ear advantage index pre and post rTMS using paired t-test.

Conclusion: According to the findings of this study, it can be concluded that the use of inhibitory rTMS protocol on the left Broca area , has no effect for shifting in the right ear advantage. For interpretation of the results, it could be stated that it may be the protocol was used in this study isn't sufficient enough to inhibit left hemisphere for linguistic processing. Another reason could be the lack of sufficient sensitivity of Dichotic Listening test to show changes in hemisphere function after TMS. However, to provide clearer description, using functional brain imaging techniques and TMS together could be helpful.

Key words: Trancranial Magnetic Stimulation (TMS), Lateralization, REA, Linguistic processing, Dichotic listening