Combining inhibitory and facilitatory repetitive transcranial magnetic stimulation (rTMS) treatment improves motor function by modulating GABA in acute ischemic stroke patients

Article type: Research Article

Authors: Chen, Qing-Mei^{a; b; 1} | Yao, Fei-Rong^{c; 1} | Sun, Hai-Wei^{d; 1} | Chen, Zhi-Guo^a | Ke, Jun^c | Liao, Juan^a | Cai, Xiu-Ying^a | Yu, Li-Qiang^a | Wu, Zhen-Yan^e | Wang, Zhi^a | Pan, Xi^a | Liu, Hao-Yu^b | Li, Li^b | Zhang, Quan-Quan^{a; 2} | Ling, Wei-Hua^{f; *; 2} | Fang, Qi^{a; *; 2}

Affiliations: [a] Department of Neurology, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu Province, China | [b] Department of Physical Medicine & Rehabilitation, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu Province, China | [c] Department of Radiology, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu Province, China | [d] Department of Emergency Medicine, The Second Affiliated Hospital of Soochow University, Suzhou, Jiangsu Province, China | [e] Health Management Center, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu Province, China | [f] Department of Emergency Medicine, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu Province, China

Correspondence: [*] Corresponding authors. Qi Fang, MD, PhD., Department of Neurology, The First Affiliated Hospital of Soochow University, Pinghai Road 899, Suzhou, 215000, Jiangsu Province, China. Tel.: +86 13606213892; E-mail: [email protected] and Weihua Ling, MD, PhD., Department of Emergency Medicine, The First Affiliated Hospital of Soochow University, Pinghai Road 899, Suzhou, 215000, Jiangsu Province, China. Tel.: +86 189 1374 3391; E-mail: [email protected].

Note: [1] The authors Qingmei Chen, Feirong Yao and Haiwei Sun contributed the same to the study, as co-first authors of this article.

Note: [2] Quanquan Zhang, Weihua Ling and Qi Fang are the co- corresponding authors.

Abstract: Background:The combination of inhibitory and facilitatory repetitive transcranial magnetic stimulation (rTMS) can improve motor function of stroke patients with undefined mechanism. It has been demonstrated that rTMS exhibits a neuro-modulatory effect by regulating the major inhibitory neurotransmitter γ-aminobutyric acid (GABA) in other diseases. Objectives:To evaluate the effect of combined inhibitory and facilitatory rTMS on GABA in the primary motor cortex (M1) for treating motor dysfunction after acute ischemic stroke. Methods:44 ischemic stroke patients with motor dysfunction were randomly divided into two groups. The treatment group was stimulated with 10 Hz rTMS at the ipsilesional M1 and 1 Hz rTMS at the contralesional M1. The sham group received bilateral sham stimulation at the motor cortices. The GABA level in the bilateral M1 was measured by proton magnetic resonance spectroscopy (1H-MRS) at 24 hours before and after rTMS stimulation. Motor function was measured using the Fugl-Meyer Assessment (FMA). The clinical assessments were performed before and after rTMS and after 3 months. Results:The treatment group exhibited a greater improvement in motor function 24 hours after rTMS compared to the sham group. The increased improvement in motor function lasted for at least 3 months after treatment. Following 4 weeks of rTMS, the GABA level in the ipsilesional M1 of the treatment group was significantly decreased compared to the sham group. Furthermore, the change of FMA score for motor function was negatively correlated to the change of the GABA:Cr ratio. Finally, the effect of rTMS on motor function outcome was partially mediated by GABA level change in response to the treatment (27.7%). Conclusions:Combining inhibitory and facilitatory rTMS can decrease the GABA level in M1, which is correlated to the improvement of motor function. Thus, the GABA level in M1 may be a potential biomarker for treatment strategy decisions regarding rTMS neuromodulatory interventions.

Keywords: Facilitatory repetitive magnetic stimulation, inhibitory repetitive transcranial magnetic stimulation, motor function, stroke, GABA, magnetic resonance spectroscopy, mediating effects, rehabilitation

DOI: 10.3233/RNN-211195

Journal: Restorative Neurology and Neuroscience, vol. 39, no. 6, pp. 419-434, 2021