Comparison of hemodynamic changes after repetitive transcranial magnetic stimulation over the anatomical hand knob and hand motor hotspot: A functional near-infrared spectroscopy study

Jinuk Kim; Heegoo Kim; Jungsoo Lee; Hwang-Jae Lee; Yoonju Na; Won Hyuk Chang; Yun-Hee Kim

doi:10.3233/RNN-201032

Comparison of hemodynamic changes after repetitive transcranial magnetic stimulation over the anatomical hand knob and hand motor hotspot: A functional near-infrared spectroscopy study

Restor Neurol Neurosci. 2020;38(6):407-417. doi: 10.3233/RNN-201032.

Authors

Jinuk Kim^{1

2}, Heegoo Kim^{1

2}, Jungsoo Lee¹, Hwang-Jae Lee^{1

2}, Yoonju Na¹, Won Hyuk Chang¹, Yun-Hee Kim^{1

2

3}

Affiliations

¹ Department of Physical and Rehabilitation Medicine, Center for Prevention and Rehabilitation, Heart Vascular Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
² Department of Health Sciences and Technology, SAIHST, Sungkyunkwan University, Seoul, Republic of Korea.
³ Department of Medical Device Management & Research, Department of Digital Health, SAIHST, Sungkyunkwan University, Seoul, Republic of Korea.

Abstract

Background: Low-frequency rTMS can induce upregulation of excitability in the contralateral hemisphere by interhemispheric interaction.

Objective: The aim of this study was to compare the effects of interhemispheric modulation on hemodynamic changes after applying low-frequency rTMS over the anatomical hand knob (HK) and the hand motor hotspot (hMHS) in the dominant motor cortex.

Methods: Ten healthy right-handed participants without a history of neurological or psychiatric symptoms (five males; 29.8±2.8 years) participated in this single-blind, randomized, cross-over study. rTMS was applied under three conditions over the dominant (left) hemisphere for 20 minutes: 1) 1 Hz rTMS stimulation on the HK (HK-rTMS), 2) 1 Hz rTMS stimulation on the hMHS (hMHS-rTMS), and 3) sham stimulation (Sham-rTMS). For all participants, functional near-infrared spectroscopy (fNIRS) was applied for measurement of cerebral oxyhemoglobin (oxyHb) and deoxyhemoglobin (deoxyHb) concentration over the non-dominant (right) hemisphere during a serial reaction time task (SRTT) with the non-dominant (left) hand before and after each condition.

Results: The average coordinates of the hMHS (x = - 39.60 mm, y = - 17.11 mm, z = 66.40 mm) were anterior and lateral to the HK (x = - 36.72 mm, y = - 28.87 mm, z = 56.41 mm). In fNIRS time-series analysis, the integral value of oxyHb wassignificantly increased over the motor cortical region of the non-dominant hemisphere after the hMHS-rTMS compared with Sham-rTMS. The HK-rTMS also showed slight increment of oxyHb concentration but without statistical significance. The SPM group analysis showed greater magnitude of the activity in hMHS-rTMS than that of HK-rTMS after stimulation (p < 0.05).

Conclusions: These results demonstrated an interhemispheric modulation effect of hemodynamic changes by 1 Hz rTMS. The hMHS produced a more robust modulation effect of 1 Hz rTMS on the contralateral hemisphere than did the HK. Therefore, the rTMS can be considered a better stimulation target than the HK.

Keywords: Interhemispheric modulation; Near-infrared spectroscopy; hand knob; hand motor hot spot; transcranial magnetic stimulation.

Publication types

Comparative Study
Randomized Controlled Trial
Research Support, Non-U.S. Gov't

MeSH terms

Adult
Cross-Over Studies
Evoked Potentials, Motor / physiology*
Female
Hand / physiology*
Hemodynamics / physiology*
Humans
Male
Motor Cortex / diagnostic imaging*
Motor Cortex / physiology*
Single-Blind Method
Spectroscopy, Near-Infrared / methods
Transcranial Magnetic Stimulation / methods*