Steady-state auditory evoked fields reflect long-term effects of repetitive transcranial magnetic stimulation in tinnitus

• Published in: Clinical neurophysiology 2019-09, Vol.130 (9), p.1665-1672
• Main Authors: Li, Lieber Po-Hung, Shiao, An-Suey, Li, Cheng-Ta, Lee, Po-Lei, Cheng, Chou-Ming, Chou, Chih-Cher, Hsieh, Jen-Chuen
• Format: Article
• Language: English
• Subjects: Adult; Aged; Cerebral Cortex - physiopathology; Evoked Potentials, Auditory; Female; Functional Laterality; Humans; Idiopathic sudden sensorineural hearing loss (ISSNHL); Magnetoencephalography (MEG); Male; Middle Aged; Repetitive transcranial magnetic stimulation (rTMS); Steady-state auditory evoked fields (SSAEFs); Tinnitus; Tinnitus - physiopathology; Tinnitus - therapy; Transcranial Magnetic Stimulation - adverse effects; Transcranial Magnetic Stimulation - methods
• ISSN: 1388-2457; 1872-8952
• DOI: 10.1016/j.clinph.2019.05.022

•Long-term effects of rTMS on steady-state auditory evoked fields (SSAEFs) in tinnitus are unknown.•We report that SSAEFs remained decreased for one month after rTMS.•SSAEFs may serve as a biomarker for long-term effects of rTMS on tinnitus. Evidence of plastic changes in tinnitus has been demonstrated in functional brain imaging. Although repetitive transcranial magnetic stimulation (rTMS) has been shown to decrease steady-state auditory evoked fields (SSAEFs) in tinnitus, the long-term consequence remained unknown. In addition, association between plastic changes as reflected by hemispheric asymmetry and tinnitus handicap inventory (THI) before and after rTMS have not been addressed. Twelve tinnitus patients received rTMS and 12 received sham stimulation. Another 12 healthy participants served as the normal hearing controls. Patients responded to the THI before the 1st session and at one month after the final session of rTMS/sham stimulation. Changes in brain activity were assessed by measuring SSAEFs. SSAEFs remained decreased one month after rTMS compared to before treatment, along with a significant reduction in THI score. There was no significant effect between the index of hemispheric asymmetry and THI score. The current study objectively demonstrated the long-term effects of rTMS on tinnitus using SSAEFs. A longitudinal study to develop an index using SSAEFs to assess the subjective severity of tinnitus is warranted. This study suggests the possible use of SSAEFs to assess the long-term effects of rTMS on tinnitus.