EFFECTS OF REPETITIVE TRANSCRANIAL MAGNETIC STIMULATION ON CHRONIC TINNITUS: AN EGYPTIAN STUDY

El-Nabil LM(1), Khalil LH (2), Amal F (1).

(1) Department of Neurology and Psychiatry, Ain Shams University, Cairo, Egypt (2) Department of Audiology, Ain Shams University, Cairo, Egypt.

OBJECTIVES: Focal brain activation in the auditory cortex has been demonstrated in chronic tinnitus. Low-frequency repetitive transcranial magnetic stimulation (rTMS) of the temporal cortex was found to  reduce tinnitus associated cortical hyper excitability. This study tested the long term effect of two weeks low-frequency rTMS, over left auditory cortex ,compared with the sham stimulation. Also the potential prognostic factors in tinnitus patients that allow  benefit of rTMS treatment were examined.

SUBJECTS AND METHODS: thirty   patients with chronic tinnitus randomly divided into two groups; group (1) fifteen patients received six real rTMS over the left temproparietal cortex every other day for two weeks, group (2) fifteen patients received six sham rTMS with the coil 90 degrees tilted behind the left ear every other day for two weeks. The treatment outcome was assessed with a tinnitus questionnaire immediately after the six sessions and monthly for three months. Therapeutic success was related to the patients’ clinical characteristics.

RESULTS: there were no significant differences in base line assessment between the two groups of patients. Repeated measures analysis by ANOVA revealed a significant “rTMS” ×”time” interaction for tinnitus complaints as shown by tinnitus questionnaire. This was because real rTMS produced greater improvement than sham rTMS.  There were negative correlations between the percentages of improvement in tinnitus questionnaire and tinnitus duration as well as hearing threshold.

CONCLUSION: Six sessions of rTMS for two weeks over the left temproparietal cortex showed  continuous and progressive inhibition of tinnitus up to three months period. Patients  with normal hearing and a short history of complaints benefited more from rTMS treatment. Tinnitus related maladaptive plastic changes due to longer duration and higher degree of hearing loss might explain  treatment outcome.

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