Past Issues

Reliability of Right-side versus Left-side Derived Parameters of Bi-pulse Transcranial Magnetic Stimulation: Preliminary Findings

Jia-Shyun Jeng, Cheng-Ta Li, Mu-Hong Chen, Wei-Chen Lin, Ya-Mei Bai, Shih-Jen Tsai

Objectives: Bi-pulse transcranial magnetic stimulation (TMS) is a non-invasive method to specifi cally assess excitation and inhibition of the motor cortex. Bi-pulse TMS has been used to study pathophysiology of psychiatric disorders such as major depressive disorder, in numerous studies. But whether inconsistent methodology, such as applying TMS pulse to left or right motor cortex, has impact on the results of previously studies, is unclear. In this study, we intended to study whether results of TMS bi-pulse paradigms obtained from left or right motor cortex are reliable. Method: We included 19 right-handed healthy subjects who received bi-pulse TMS procedures applying stimuli to bilateral motor cortices twice. They were assessed at baseline (week 1) and at the end of 8 weeks (week 8). Then, we compared the differences between left and right side variables. Results: There was not signifi cant difference of bi-pulse TMS parameters between left and right hemisphere, respectively, at week 1 or at week 8. By using Pearson’s correlation, there was signifi cant highly correlated to motor evoked potential (MEP) -100% (r = 0.781, p < 0.001), MEP-active (r = 0.751, p < 0.001), MEP-size (r = 0.734, p < 0.001) from right motor cortex between week 1 and week 8. TMS measurements from the non-dominant (right) motor cortex showed more reliable than the dominant (left) side. Conclusion: Our study provided evidence that the non-dominant (right-side) measures were more reliable than the dominant (left-side) hemisphere.
Key Word bi-pulse TMS, TMS paradigms, hemisphere asymmetry, reliability
Editorial Committe, Taiwanese Journal of Psychiatry
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